A head injury is any injury that results in trauma to the skull or brain . The terms traumatic brain injury and head injury are often used interchangeably in the medical literature. Because head injuries cover such a broad scope of injuries, there are many causes—including accidents, falls, physical assault, or traffic accidents—that can cause head injuries.
126-404: A concussion , also known as a mild traumatic brain injury ( mTBI ), is a head injury that temporarily affects brain functioning . Symptoms may include loss of consciousness ; memory loss; headaches ; difficulty with thinking, concentration, or balance; nausea; blurred vision ; dizziness; sleep disturbances, and mood changes . Any of these symptoms may begin immediately, or appear days after
252-413: A lucid interval , during which a patient appears conscious only to deteriorate later. Symptoms of skull fracture can include: Because brain injuries can be life-threatening, even people with apparently slight injuries, with no noticeable signs or complaints, require close observation; They have a chance for severe symptoms later on. The caretakers of those patients with mild trauma who are released from
378-506: A CT scan or an MRI may be required to rule out severe head injuries. Routine imaging is not required to diagnose concussion. Prevention of concussions includes the use of a helmet when bicycling or motorbiking . Treatment includes physical and mental rest for 1–2 days, with a gradual step-wise return to activities, school, and work. Prolonged periods of rest may slow recovery and result in greater depression and anxiety. Paracetamol (acetaminophen) or NSAIDs may be recommended to help with
504-463: A blow to the head that could make the person's physical, cognitive, and emotional behaviors irregular. Symptoms may include clumsiness, fatigue , confusion , nausea , blurry vision , headaches , and others. Mild concussions are associated with sequelae . Severity is measured using various concussion grading systems . A slightly greater injury is associated with both anterograde and retrograde amnesia (inability to remember events before or after
630-431: A brain injury depend on location and the body's response to injury. Even a mild concussion can have long term effects that may not resolve. The foundation for understanding human behavior and brain injury can be attributed to the case of Phineas Gage and the famous case studies by Paul Broca. The first case study on Phineas Gage's head injury is one of the most astonishing brain injuries in history. In 1848, Phineas Gage
756-547: A brain injury. Determining the ideal time for a person to return to work will depend on personal factors and job-related factors including the intensity of the job and the risk of falling or hitting one's head at work during recovery. After the required initial recovery period of complete rest (24–48 hours after the concussion began), gradually and safely returning to the workplace with accommodations and support in place, should be prioritized over staying home and resting for long periods of time, to promote physical recovery and reduce
882-480: A clinical setting given multiple factors about the patient—including mechanism/location of the injury, age of the patient, and GCS score. Symptoms of brain injuries can also be influenced by the location of the injury and as a result, impairments are specific to the part of the brain affected. Lesion size is correlated with severity, recovery, and comprehension. Brain injuries often create impairment or disability that can vary greatly in severity. Studies show there
1008-528: A common occurrence in those who experience a head injury. Neurotoxicity is another cause of brain damage that typically refers to selective, chemically induced neuron /brain damage. Head injuries include both injuries to the brain and those to other parts of the head, such as the scalp and skull . Head injuries can be closed or open. A closed (non-missile) head injury is where the dura mater remains intact. The skull can be fractured, but not necessarily. A penetrating head injury occurs when an object pierces
1134-494: A concussion are not " post-traumatic seizures ", and, unlike post-traumatic seizures, are not predictive of post-traumatic epilepsy , which requires some form of structural brain damage, not just a momentary disruption in normal brain functioning. Concussive convulsions are thought to result from temporary loss or inhibition of motor function and are not associated either with epilepsy or with more serious structural damage. They are not associated with any particular sequelae and have
1260-484: A concussion, however some may experience a prolonged recovery. There is no single physical test, blood test (or fluid biomarkers), or imaging test that can be used to determine when a person has fully recovered from concussion. A person's recovery may be influenced by a variety of factors that include age at the time of injury, intellectual abilities, family environment, social support system, occupational status, coping strategies, and financial circumstances. Factors such as
1386-465: A continuum of muscle activation for smooth motor control during various tasks. Directionality of a movement has an effect on how the motor task is performed (i.e. walking forward vs. walking backward, each uses different levels of contraction in different muscles). Moreover, it is thought that the muscle synergies limited the number of degrees of freedom by constraining the movements of certain joints or muscles (flexion and extension synergies). However,
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#17327881235041512-426: A doctor for an initial medical assessment and for suggestions on recovery, however, medical clearance is not required for a student to return to school. Since students may appear 'normal', continuing education of relevant school personnel may be needed to ensure appropriate accommodations are made such as part-days and extended deadlines. Accommodations should be based on the monitoring of symptoms that are present during
1638-438: A few methods used to diagnose a head injury. A healthcare professional will ask the patient questions revolving around the injury as well as questions to help determine in what ways the injury is affecting function. In addition to this hearing, vision, balance, and reflexes may also be assessed as an indicator of the severity of the injury. A non-contrast CT of the head should be performed immediately in all those who have sustained
1764-436: A head injury occurs and manifest as clinical, biochemical, and radiological changes. An MRI may also be conducted to determine if someone has abnormal growths or tumors in the brain or to determine if the patient has had a stroke. Glasgow Coma Scale (GCS) is the most widely used scoring system used to assess the level of severity of a brain injury. This method is based on objective observations of specific traits to determine
1890-798: A head injury. Among these are the Canadian Head CT rule, the PECARN Head Injury/Trauma Algorithm, and the New Orleans/Charity Head Injury/Trauma Rule all help clinicians make these decisions using easily obtained information and noninvasive practices. Brain injuries are very hard to predict in the outcome. Many tests and specialists are needed to determine the likelihood of the prognosis. People with minor brain damage can have debilitating side effects; not just severe brain damage has debilitating effects. The side-effects of
2016-464: A headache. Prescribed aerobic exercise may improve recovery. Physiotherapy may be useful for persisting balance problems, headache, or whiplash; cognitive behavioral therapy may be useful for mood changes. Evidence to support the use of hyperbaric oxygen therapy and chiropractic therapy is lacking. Worldwide, concussions are estimated to affect more than 3.5 per 1,000 people a year. Concussions are classified as mild traumatic brain injuries and are
2142-521: A loss of consciousness. However, the definition has evolved over time to include a change in consciousness, such as amnesia, although controversy continues about whether the definition should include only those injuries in which loss of consciousness occurs. This debate resurfaces in some of the best-known concussion grading scales, in which those episodes involving loss of consciousness are graded as being more severe than those without. Definitions of mild traumatic brain injury (mTBI) were inconsistent until
2268-465: A medical assessment. Up to one-third of people with concussion experience longer or persisting concussion symptoms, also known as post concussion syndrome or persisting symptoms after concussion , which is defined as concussion symptoms lasting for 4 weeks or longer in children and adolescents, and symptoms lasting for more than 14 days in an adult. The severity of the initial symptoms is the strongest predictor of recovery time in adults. Headaches are
2394-465: A moderate or severe head injury. A CT is an imaging technique that allows physicians to see inside the head without surgery in order to determine if there is internal bleeding or swelling in the brain. Computed tomography (CT) has become the diagnostic modality of choice for head trauma due to its accuracy, reliability, safety, and wide availability. The changes in microcirculation, impaired auto-regulation, cerebral edema, and axonal injury start as soon as
2520-403: A person has symptoms. Resting completely for longer than 24–48 hours following concussion has been shown to be associated with longer recovery. The resumption of low-risk school activities should begin as soon as the student feels ready and has completed an initial period of cognitive rest of no more than 24–48 hours following the acute injury. Long absences from school are not suggested, however;
2646-412: A person's risk of having another. Having previously sustained a sports concussion has been found to be a strong factor increasing the likelihood of a concussion in the future. People who have had a concussion seem more susceptible to another one, particularly if the new injury occurs before symptoms from the previous concussion have completely gone away. It is also a negative process if smaller impacts cause
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#17327881235042772-497: A physician or nurse practitioner to rule out severe injuries to the brain and cervical spine, mental health conditions, or other medical conditions. Diagnosis is based on physical and neurological examination findings, duration of unconsciousness (usually less than 30 minutes) and post-traumatic amnesia (usually less than 24 hours), and the Glasgow Coma Scale (people with mTBI have scores of 13 to 15). A CT scan or MRI
2898-430: A previous head injury or a coexisting medical condition have been found to predict longer-lasting persisting concussion symptoms. Other factors that may lengthen recovery time after mTBI include psychological problems such as substance abuse or clinical depression , poor health before the injury or additional injuries sustained during it, and life stress. Longer periods of amnesia or loss of consciousness immediately after
3024-438: A previously recommended recovery technique, has limited effectiveness. A recommended treatment in both children and adults with symptoms beyond 4 weeks involves an active rehabilitation program with reintroduction of non-contact aerobic activity. Progressive physical exercise has been shown to reduce long-term post-concussive symptoms. Symptoms usually go away on their own within months but may last for years. The question of whether
3150-425: A prior history of concussion. The mechanism of injury involves either a direct blow to the head or forces elsewhere on the body that are transmitted to the head. This is believed to result in neuron dysfunction, as there are increased glucose requirements, but not enough blood supply. A thorough evaluation by a qualified medical provider working in their scope of practice (such as a physician or nurse practitioner)
3276-695: A series of graded steps. These steps include: At each step, the person should not have worsening or new symptoms for at least 24 hours before progressing to the next. If symptoms worsen or new symptoms begin, athletes should drop back to the previous level for at least another 24 hours. Intercollegiate or professional athletes, are typically followed closely by team athletic trainers during this period but others may not have access to this level of health care and may be sent home with minimal monitoring. Medications may be prescribed to treat headaches, sleep problems and depression. Analgesics such as ibuprofen can be taken for headaches, but paracetamol (acetaminophen)
3402-400: A severe headache, have mismatched pupil sizes, and/or be unable to move certain parts of the body. While these symptoms happen immediately after a head injury occurs, many problems can develop later in life. Alzheimer's disease , for example, is much more likely to develop in a person who has experienced a head injury. Brain damage, which is the destruction or degeneration of brain cells, is
3528-505: A single signal, rather than independently. As the muscles of limb controlling movement are linked, it is likely that the error and variability are also shared, providing flexibility and compensating for errors in the individual motor components. The current method of finding muscle synergies is to use statistical and/or coherence analyses on measured EMG ( electromyography ) signals of different muscles during movements. A reduced number of control elements (muscle synergies) are combined to form
3654-752: A state in which brain function is temporarily impaired and "mTBI" to imply a pathophysiological state, but in practice, few researchers and clinicians distinguish between the terms. Descriptions of the condition, including the severity and the area of the brain affected, are now used more often than "concussion" in clinical neurology. Prevention of mTBI involves general measures such as wearing seat belts , using airbags in cars, and protective equipment such as helmets for high-risk sports. Older people are encouraged to reduce fall risk by keeping floors free of clutter and wearing thin, flat shoes with hard soles that do not interfere with balance. Protective equipment such as helmets and other headgear and policy changes such as
3780-462: A stroke patient. The patient experienced neither speech nor hearing impairments but had a few brain deficits. These deficits included: lacking the ability to comprehend what was spoken to him and the words written down. After his death, Wernicke examined his autopsy that found a lesion located in the left temporal region. This area became known as Wernicke's area . Wernicke later hypothesized the relationship between Wernicke's area and Broca's area, which
3906-858: A subsequent force transmission to the head are also causes. A retrospective survey in 2005 suggested that more than 88% of concussions are unrecognized. Particularly, many younger athletes struggle with identifying their concussions, which often result in the non-disclosure of concussions and consequently under-representing the incidence of concussions in the context of sport. Diagnosis can be complex because concussion shares symptoms with other conditions. For example, persisting concussion symptoms such as cognitive problems may be misattributed to brain injury when, in fact, due to post-traumatic stress disorder (PTSD). There are no fluid biomarkers (i.e., blood or urine tests) that are validated for diagnosing concussion in children or adolescents. No single definition of concussion, minor head injury, or mild traumatic brain injury
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4032-422: A system of interest at a selected level of analysis, and a performance variable refers to the potentially important variables produced by the system as a whole. For example, in a multi-joint reaching task, the angles and the positions of certain joints are the elemental variables, and the performance variables are the endpoint coordinates of the hand. This hypothesis proposes that the controller (the brain) acts in
4158-410: A task-dependent manner. In other words, it is likely that a synergy is structured for a particular action and not for the possible activation levels of the components themselves. Work from Emilio Bizzi suggests that sensory feedback adapts synergies to fit behavioral constraints, but may differ in an experience-dependent manner. Synergies allow the components for a particular task to be controlled with
4284-432: A trusted person with instructions to return if they display worsening symptoms or those that might indicate an emergent condition ("red flag symptoms") such as change in consciousness, convulsions, severe headache, extremity weakness, vomiting, new bleeding or deafness in either or both ears. Education about symptoms, their management, and their normal time course, may lead to an improved outcome. Physical and cognitive rest
4410-608: Is a correlation between brain lesion and language, speech, and category-specific disorders. Wernicke's aphasia is associated with anomia , unknowingly making up words ( neologisms ), and problems with comprehension. The symptoms of Wernicke's aphasia are caused by damage to the posterior section of the superior temporal gyrus . Damage to the Broca's area typically produces symptoms like omitting functional words ( agrammatism ), sound production changes, dyslexia , dysgraphia , and problems with comprehension and production. Broca's aphasia
4536-607: Is a functional or structural phenomenon is ongoing. Structural damage has been found in the mildly traumatically injured brains of animals, but it is not clear whether these findings would apply to humans. Such changes in brain structure could be responsible for certain symptoms such as visual disturbances, but other sets of symptoms, especially those of a psychological nature, are more likely to be caused by reversible pathophysiological changes in cellular function that occur after concussion, such as alterations in neurons' biochemistry. These reversible changes could also explain why dysfunction
4662-401: Is a subsequent lower metabolic state which may persist for up to 4 weeks after injury. A completely separate pathway involves a large amount of calcium accumulating in cells, which may impair oxidative metabolism and begin further biochemical pathways that result in cell death. Again, both of these main pathways have been established from animal studies and the extent to which they apply to humans
4788-539: Is a term used to differentiate brain injuries occurring after birth from injury, from a genetic disorder , or from a congenital disorder . Unlike a broken bone where trauma to the body is obvious, head trauma can sometimes be conspicuous or inconspicuous. In the case of an open head injury, the skull is cracked and broken by an object that makes contact with the brain. This leads to bleeding. Other obvious symptoms can be neurological in nature. The person may become sleepy, behave abnormally, lose consciousness, vomit, develop
4914-400: Is a worsening headache , seizure , one-sided weakness, or has persistent vomiting. To combat overuse of head CT scans yielding negative intracranial hemorrhage results, which unnecessarily exposes patients to radiation and increase time in the hospital and cost of the visit, multiple clinical decision support rules have been developed to help clinicians weigh the option to scan a patient with
5040-567: Is considered a focal brain injury ; that is, it occurs in a localized spot rather than causing diffuse damage over a wider area. Intra-axial hemorrhage is bleeding within the brain itself, or cerebral hemorrhage . This category includes intraparenchymal hemorrhage , or bleeding within the brain tissue, and intraventricular hemorrhage , bleeding within the brain's ventricles (particularly of premature infants ). Intra-axial hemorrhages are more dangerous and harder to treat than extra-axial bleeds. Extra-axial hemorrhage, bleeding that occurs within
5166-491: Is frequently temporary. A task force of head injury experts called the Concussion In Sport Group met in 2001 and decided that "concussion may result in neuropathological changes but the acute clinical symptoms largely reflect a functional disturbance rather than structural injury." Using animal studies, the pathology of a concussion seems to start with mechanical shearing and stretching forces disrupting
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5292-607: Is guarded. Diffuse axonal injury , or DAI, usually occurs as the result of an acceleration or deceleration motion, not necessarily an impact. Axons are stretched and damaged when parts of the brain of differing density slide over one another. Prognoses vary widely depending on the extent of the damage. Overlying scalp laceration and soft tissue disruption in continuity with a skull fracture constitutes "compound head injury", and has higher rates of infection, unfavorable neurologic outcome, delayed seizures, mortality, and duration of hospital stay. Three categories used for classifying
5418-400: Is indicative of damage to the posterior inferior frontal gyrus of the brain. An impairment following damage to a region of the brain does not necessarily imply that the damaged area is wholly responsible for the cognitive process which is impaired, however. For example, in pure alexia , the ability to read is destroyed by a lesion damaging both the left visual field and the connection between
5544-465: Is inherently variable because there are many ways of coordinating body parts to achieve the intended movement goal. This is because the degrees of freedom (DOF) is large for most movements due to the many associated neuro- musculoskeletal elements. Some examples of non-repeatable movements are when pointing or standing up from sitting. Actions and movements can be executed in multiple ways because synergies (as described below) can vary without changing
5670-609: Is needed include 'red flag symptoms' or 'concussion danger signs': worsening headaches, persisting vomiting, increasing disorientation or a deteriorating level of consciousness, seizures, and unequal pupil size . Those with such symptoms, or those who are at higher risk of a more serious brain injury, require an emergency medical assessment. Brain imaging such as a CT scan or MRI may be suggested, but should be avoided unless there are progressive neurological symptoms, focal neurological findings, or concern of skull fracture on exam. Diagnosis of concussion requires an assessment performed by
5796-400: Is needed. Observation to monitor for worsening condition is an important part of treatment. While it is common advice that someone who is concussed should not be allowed to fall asleep in case they go into a coma , for general cases this is not supported by current evidence. People may be released after assessment from their primary care medical clinic, hospital, or emergency room to the care of
5922-821: Is not required or suggested for most children and adults. If the Glasgow coma scale is less than 15 at two hours or less than 14 at any time, a CT is recommended. In addition, a CT scan is more likely to be performed if observation after discharge is not assured or intoxication is present, there is suspected increased risk for bleeding, age greater than 60, or less than 16. Most concussions, without complication, cannot be detected with MRI or CT scans. However, changes have been reported on MRI and SPECT imaging in those with concussion and normal CT scans, and persisting concussion symptoms may be associated with abnormalities visible on SPECT and PET scans . Mild head injury may or may not produce abnormal EEG readings. A blood test known as
6048-547: Is not required to diagnose concussion. Neuropsychological tests such as the SCAT5/child SCAT5 may be suggested measure cognitive function. Such tests may be administered hours, days, or weeks after the injury, or at different times to demonstrate any trend. Some athletes are also being tested pre-season (pre-season baseline testing) to provide a baseline for comparison in the event of an injury, though this may not reduce risk or affect return to play and baseline testing
6174-437: Is preferred to minimize the risk of intracranial hemorrhage. Concussed individuals are advised not to use alcohol or other drugs that have not been approved by a doctor as they can impede healing. Activation database-guided EEG biofeedback has been shown to return the memory abilities of the concussed individual to levels better than the control group. About one percent of people who receive treatment for mTBI need surgery for
6300-442: Is recommended for the first 24–48 hours following a concussion after which injured persons should gradually start gentle low-risk physical and cognitive activities that do not make current symptoms worse or bring on new symptoms. Any activity for which there is a risk of contact, falling, or bumping the head should be avoided until the person has clearance from a doctor or nurse practitioner. Low-risk activities can be started even while
6426-423: Is required to rule out life-threatening head injuries, injuries to the cervical spine, and neurological conditions and to use information obtained from the medical evaluation to diagnose a concussion. Glasgow coma scale score 13 to 15, loss of consciousness for less than 30 minutes, and memory loss for less than 24 hours may be used to rule out moderate or severe traumatic brain injuries . Diagnostic imaging such as
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#17327881235046552-442: Is still somewhat unclear. Head trauma recipients are initially assessed to exclude a more severe emergency such as an intracranial hemorrhage or other serious head or neck injuries. This includes the "ABCs" (airway, breathing, circulation) and stabilization of the cervical spine , which is assumed to be injured in any athlete who is found to be unconscious after head or neck injury. Indications that screening for more serious injury
6678-433: Is thought to be the major component in concussion and its severity. As of 2007, studies with athletes have shown that the amount of force and the location of the impact are not necessarily correlated with the severity of the concussion or its symptoms, and have called into question the threshold for concussion previously thought to exist at around 70–75 g . The parts of the brain most affected by rotational forces are
6804-566: Is universally accepted. In 2001, the expert Concussion in Sport Group of the first International Symposium on Concussion in Sport defined concussion as "a complex pathophysiological process affecting the brain, induced by traumatic biomechanical forces." It was agreed that concussion typically involves temporary impairment of neurological function that heals by itself within time, and that neuroimaging normally shows no gross structural changes to
6930-655: The Glasgow Coma Scale . Concussion falls under the classification of mild TBI, but it is not clear whether concussion is implied in mild brain injury or mild head injury. "mTBI" and "concussion" are often treated as synonyms in medical literature but other injuries such as intracranial hemorrhages (e.g. intra-axial hematoma , epidural hematoma , and subdural hematoma ) are not necessarily precluded in mTBI or mild head injury, as they are in concussion. mTBI associated with abnormal neuroimaging may be considered "complicated mTBI". "Concussion" can be considered to imply
7056-732: The World Health Organization 's International Statistical Classification of Diseases and Related Health Problems (ICD-10) provided a consistent, authoritative definition across specialties in 1992. Since then, various organizations such as the American Congress of Rehabilitation Medicine and the American Psychiatric Association in its Diagnostic and Statistical Manual of Mental Disorders have defined mTBI using some combination of loss of consciousness , post-traumatic amnesia , and
7182-517: The brain . Such forces can occur when the head is struck by an object or surface (a 'direct impact'), or when the torso rapidly changes position (i.e. from a body check ) and force is transmitted to the head (an 'indirect impact'). Forces may cause linear, rotational, or angular movement of the brain or a combination of them. In rotational movement, the head turns around its center of gravity, and in angular movement, it turns on an axis, not through its center of gravity. The amount of rotational force
7308-543: The frontal lobe . Angular accelerations of 4600, 5900, or 7900 rad /s are estimated to have 25, 50, or 80% risk of mTBI respectively. In both animals and humans, mTBI can alter the brain's physiology for hours to years, setting into motion a variety of pathological events. As one example, in animal models, after an initial increase in glucose metabolism, there is a subsequent reduced metabolic state which may persist for up to four weeks after injury. Though these events are thought to interfere with neuronal and brain function,
7434-401: The fusiform gyrus often result in prosopagnosia , the inability to distinguish faces and other complex objects from each other. Lesions in the amygdala would eliminate the enhanced activation seen in occipital and fusiform visual areas in response to fear with the area intact. Amygdala lesions change the functional pattern of activation to emotional stimuli in regions that are distant from
7560-668: The metabolic processes that follow concussion are reversible in a large majority of affected brain cells ; however, a few cells may die after the injury. Included in the cascade of events unleashed in the brain by concussion is impaired neurotransmission , loss of regulation of ions , deregulation of energy use and cellular metabolism, and a reduction in cerebral blood flow . Excitatory neurotransmitters , chemicals such as glutamate that serve to stimulate nerve cells, are released in excessive amounts. The resulting cellular excitation causes neurons to fire excessively. This creates an imbalance of ions such as potassium and calcium across
7686-419: The midbrain and diencephalon . It is thought that the forces from the injury disrupt the normal cellular activities in the reticular activating system located in these areas and that this disruption produces the loss of consciousness often seen in concussion. Other areas of the brain that may be affected include the upper part of the brain stem , the fornix , the corpus callosum , the temporal lobe , and
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#17327881235047812-655: The parietal lobes may result in agnosia , an inability to recognize complex objects, smells, or shapes, or amorphosynthesis , a loss of perception on the opposite side of the body. Head injuries can be caused by a large variety of reasons. All of these causes can be put into two categories used to classify head injuries; those that occur from impact (blows) and those that occur from shaking. Common causes of head injury due to impact are motor vehicle traffic collisions , home and occupational accidents, falls, assault , and sports related accidents. Head injuries from shaking are most common amongst infants and children. According to
7938-401: The supplementary motor area (SMA), the cingulate motor cortex (CMC), the primary motor cortex (M1), and the cerebellum . Several studies have proposed that inter-limb coordination can be modeled by coupled phase oscillators , a key component of a central pattern generator (CPG) control architecture. In this framework, the coordination between limbs is dictated by the relative phase of
8064-584: The Brain Trauma Indicator was approved in the United States in 2018 and may be able to rule out the risk of intracranial bleeding and thus the need for a CT scan for adults. Concussion may be under-diagnosed because of the lack of the highly noticeable signs and symptoms while athletes may minimize their injuries to remain in the competition. Direct impact to the head is not required for a concussion diagnosis, as other bodily impacts with
8190-574: The Canadian CT Head Rule or the New Orleans/Charity Head injury/Trauma Rule to decide if the patient needs further imaging studies or observation only. Rules like these are usually studied in depth by multiple research groups with large patient cohorts to ensure accuracy given the risk of adverse events in this area. There is a subspecialty certification available for brain injury medicine that signifies expertise in
8316-853: The United States CDC , 32% of traumatic brain injuries (another, more specific, term for head injuries) are caused by falls, 10% by assaults, 16.5% by being struck by or against something, 17% by motor vehicle accidents, and 21% by other/unknown ways. In addition, the highest rate of injury is among children ages 0–14 and adults age 65 and older. Brain injuries that include brain damage can also be brought on by exposure to toxic chemicals, lack of oxygen, tumors, infections, and stroke. Possible causes of widespread brain damage include birth hypoxia, prolonged hypoxia (shortage of oxygen ), poisoning by teratogens (including alcohol ), infection , and neurological illness . Brain tumors can increase intracranial pressure, causing brain damage. There are
8442-434: The amygdala. Other lesions to the visual cortex have different effects depending on the location of the damage. Lesions to V1 , for example, can cause blindsight in different areas of the brain depending on the size of the lesion and location relative to the calcarine fissure . Lesions to V4 can cause color-blindness , and bilateral lesions to MT/V5 can cause the loss of the ability to perceive motion. Lesions to
8568-404: The banning of body checking in youth hockey leagues have been found to reduce the number and severity of concussions in athletes. Secondary prevention such as a Return to Play Protocol for an athlete may reduce the risk of repeat concussions. New "Head Impact Telemetry System" technology is being placed in helmets to study injury mechanisms and may generate knowledge that will potentially help reduce
8694-491: The biological reason for muscle synergies is debated. In addition to the understanding of muscle coordination, muscle synergies have also been instrumental in assessing motor impairments, helping to identify deviations in typical movement patterns and underlying neurological disorders. Another hypothesis proposes that the central nervous system does not eliminate the redundant degrees of freedom , but instead uses them to ensure flexible and stable performance of motor tasks at
8820-489: The brain as the result of the condition. However, although no structural brain damage occurs according to the classic definition, some researchers have included injuries in which structural damage has occurred, and the National Institute for Health and Clinical Excellence definition includes physiological or physical disruption in the brain's synapses . Also, by definition, concussion has historically involved
8946-621: The brain has been severely damaged by trauma, a neurosurgical evaluation may be useful. Treatments may involve controlling elevated intracranial pressure. This can include sedation, paralytics, cerebrospinal fluid diversion. Second-line alternatives include decompressive craniectomy (Jagannathan et al. found a net 65% favorable outcomes rate in pediatric patients), barbiturate coma, hypertonic saline, and hypothermia. Although all of these methods have potential benefits, there has been no randomized study that has shown unequivocal benefit. Clinicians will often consult clinical decision support rules such as
9072-465: The brains of concussion patients who died from other causes, but inadequate blood flow to the brain due to other injuries may have contributed. Findings from a study of the brains of deceased NFL athletes who received concussions suggest that lasting damage is done by such injuries. This damage, the severity of which increases with the cumulative number of concussions sustained, can lead to a variety of other health issues. The debate over whether concussion
9198-465: The byproduct lactate . For a period of minutes to days after a concussion, the brain is especially vulnerable to changes in intracranial pressure , blood flow, and anoxia . According to studies performed on animals (which are not always applicable to humans), large numbers of neurons can die during this period in response to slight, normally innocuous changes in blood flow. Concussion involves diffuse (as opposed to focal) brain injury , meaning that
9324-565: The cell membrane of nerve cells through "mechanoporation". This results in potassium outflow from within the cell into the extracellular space with the subsequent release of excitatory neurotransmitters including glutamate which leads to enhanced potassium extrusion, in turn resulting in sustained depolarization, impaired nerve activity and potential nerve damage. Human studies have failed to identify changes in glutamate concentration immediately post-mTBI, though disruptions have been seen 3 days to 2 weeks post-injury. In an effort to restore ion balance,
9450-484: The cell membranes of neurons (a process like excitotoxicity ). At the same time, cerebral blood flow is relatively reduced for unknown reasons, though the reduction in blood flow is not as severe as it is in ischemia . Thus cells get less glucose than they normally do, which causes an "energy crisis". Concurrently with these processes, the activity of mitochondria may be reduced, which causes cells to rely on anaerobic metabolism to produce energy, increasing levels of
9576-421: The cervical spine, and neurological conditions are ruled out, exclusion of neck or head injury, observation should be continued for several hours. If repeated vomiting, worsening headache, dizziness, seizure activity, excessive drowsiness, double vision, slurred speech, unsteady walk, or weakness or numbness in arms or legs, or signs of basilar skull fracture develop, immediate assessment in an emergency department
9702-432: The cost of motor variability. The Uncontrolled Manifold (UCM) Hypothesis provides a way to quantify a "muscle synergy" in this framework. This hypothesis defines "synergy" a little differently from that stated above; a synergy represents an organization of elemental variables (degrees of freedom) that stabilizes an important performance variable. Elemental variable is the smallest sensible variable that can be used to describe
9828-401: The cost of transport. Like vertebrates, drosophila change their interleg coordination pattern in a speed-dependent manner. However, these coordination patterns follow a continuum rather than distinct gaits. In bimanual tasks (tasks involving two hands), it was found that the functional segments of the two hands are tightly synchronized. One of the postulated theories for this functionality is
9954-453: The dysfunction occurs over a widespread area of the brain rather than in a particular spot. It is thought to be a milder type of diffuse axonal injury , because axons may be injured to a minor extent due to stretching. Animal studies in which rodents were concussed have revealed lifelong neuropathological consequences such as ongoing axonal degeneration and neuroinflammation in subcortical white matter tracts. Axonal damage has been found in
10080-415: The existence of a higher, "coordinating schema" that calculates the time it needs to perform each individual task and coordinates it using a feedback mechanism . There are several areas of the brain that are found to contribute to temporal coordination of the limbs needed for bimanual tasks, and these areas include the premotor cortex (PMC), the parietal cortex , the mesial motor cortices, more specifically
10206-434: The existence of muscle synergies as a neural strategy of simplifying the control of multiple degrees of freedom. A functional muscle synergy is defined as a pattern of co-activation of muscles recruited by a single neural command signal. One muscle can be part of multiple muscle synergies, and one synergy can activate multiple muscles. Synergies are learned, rather than being hardwired, like motor programs, and are organized in
10332-689: The eyes, inability to awaken from sleep, weakness in the extremities, and a loss of coordination. In cases of severe brain injuries, the likelihood of areas with permanent disability is great, including neurocognitive deficits , delusions (often, to be specific, monothematic delusions ), speech or movement problems, and intellectual disability . There may also be personality changes. The most severe cases result in coma or even persistent vegetative state . Symptoms observed in children include changes in eating habits, persistent irritability or sadness, changes in attention, disrupted sleeping habits, or loss of interest in toys. Presentation varies according to
10458-415: The frontal lobe lesion from an autopsy. The second patient had similar speech impairments, supporting his findings on language localization. The results of both cases became a vital verification of the relationship between speech and the left cerebral hemisphere. The affected areas are known today as Broca's area and Broca's Aphasia. A few years later, a German neuroscientist, Carl Wernicke , consulted on
10584-502: The hand to the target and (2) subjects move their free hand to the target. Each condition showed different trajectories: (1) straight path and (2) curved path. Eye–hand coordination is associated with how eye movements are coordinated with and influence hand movements. Prior work implicated eye movement in the motor planning of goal-directed hand movement. The following pages are recommended for understanding how coordination patterns are learned or adapted: Nikolai Bernstein proposed
10710-466: The hospital are frequently advised to rouse the patient several times during the next 12 to 24 hours to assess for worsening symptoms. The Glasgow Coma Scale (GCS) is a tool for measuring the degree of unconsciousness and is thus a useful tool for determining the severity of the injury. The Pediatric Glasgow Coma Scale is used in young children. The widely used PECARN Pediatric Head Injury/Trauma Algorithm helps physicians weigh risk-benefit of imaging in
10836-407: The impact causes the head to move, the injury may be worsened, because the brain may ricochet inside the skull causing additional impacts, or the brain may stay relatively still (due to inertia) but be hit by the moving skull (both are contrecoup injuries). Specific problems after head injury can include A concussion is a form of a mild traumatic brain injury (TBI). This injury is a result due to
10962-516: The incidence of concussion in sport, younger athletes often do not disclose concussions and their symptoms. Common reasons for non-disclosure include a lack of awareness of the concussion, the belief that the concussion was not serious enough, and not wanting to leave the game or team due to their injury. Self-reported concussion rates among U-20 and elite rugby union players in Ireland are 45–48%, indicating that many concussions go unreported. Changes to
11088-641: The injury may indicate longer recovery times from residual symptoms. Other strong factors include participation in a contact sport and body mass size. Most children recover completely from concussion in less than four weeks, however 15–30% of youth may experience symptoms that last longer than a month. Mild traumatic brain injury recovery time in people over age 65 may have increased complications due to elevated health concerns, or comorbidities . This often results in longer hospitalization duration, poorer cognitive outcomes, and higher mortality rates. For unknown reasons, having had one concussion significantly increases
11214-424: The injury). The amount of time that the amnesia is present correlates with the severity of the injury. In all cases, the patients develop post concussion syndrome , which includes memory problems, dizziness, tiredness, sickness and depression . Cerebral concussion is the most common head injury seen in children. Types of intracranial hemorrhage are roughly grouped into intra-axial and extra-axial. The hemorrhage
11340-569: The injury. Concussion should be suspected if a person indirectly or directly hits their head and experiences any of the symptoms of concussion. Symptoms of a concussion may be delayed by 1–2 days after the accident. It is not unusual for symptoms to last 2 weeks in adults and 4 weeks in children. Fewer than 10% of sports-related concussions among children are associated with loss of consciousness. Common causes include motor vehicle collisions , falls , sports injuries , and bicycle accidents . Risk factors include physical violence, drinking alcohol and
11466-446: The injury. Some patients with head trauma stabilize and other patients deteriorate. A patient may present with or without neurological deficit . Patients with concussion may have a history of seconds to minutes unconsciousness, then normal arousal. Disturbance of vision and equilibrium may also occur. Common symptoms of head injury include coma , confusion, drowsiness, personality change, seizures , nausea and vomiting , headache and
11592-470: The most common mTBI symptom. Others include dizziness, vomiting, nausea, lack of motor coordination , difficulty balancing , or other problems with movement or sensation. Visual symptoms include light sensitivity , seeing bright lights, blurred vision , and double vision . Tinnitus , or a ringing in the ears, is also commonly reported. In one in about seventy concussions, concussive convulsions occur, but seizures that take place during or immediately after
11718-577: The most common type of TBIs. Males and young adults are most commonly affected. Outcomes are generally good. Another concussion before the symptoms of a prior concussion have resolved is associated with worse outcomes. Repeated concussions may also increase the risk in later life of chronic traumatic encephalopathy , Parkinson's disease and depression . Concussion symptoms vary between people and include physical, cognitive, and emotional symptoms. Symptoms may appear immediately or be delayed by 1–2 days. Delayed onset of symptoms may still be serious and require
11844-467: The most effective. CT scans can show brain bleeds, fractures of the skull, fluid build up in the brain that will lead to increased cranial pressure. MRI is able to better detect smaller injuries, detect damage within the brain, diffuse axonal injury, injuries to the brainstem, posterior fossa, and subtemporal and sub frontal regions. However, patients with pacemakers, metallic implants, or other metal within their bodies are unable to have an MRI done. Typically
11970-467: The movement of the limb that the feedback is acting on. Intra-limb coordination involves orchestrating the movement of the limb segments that make up a single limb. This coordination can be achieved by controlling/restricting the joint trajectories and/or torques of each limb segment as required to achieve the overall desired limb movement, as demonstrated by the joint-space model. Alternatively, intra-limb coordination can be accomplished by just controlling
12096-464: The muscles required for lifting and articulating the bottle so that the water can be poured into the glass. (4) terminating the action by placing the empty bottle back on the table. Hand-eye coordination is also required in the above task. There is simultaneous coordination between hand and eye movement as dictated by the multi-sensory integration of proprioceptive and visual information. Additional levels of coordination are required depending on if
12222-472: The oscillators representing the limbs. Specifically, an oscillator associated with a particular limb determines the progression of that limb through its movement cycle (e.g. step cycle in walking). In addition to driving the relative limb movement in a forward manner, sensory feedback can be incorporated into the CPG architecture. This feedback also dictates the coordination between the limbs by independently modifying
12348-459: The other imaging techniques are not used in a clinical setting because of the cost, lack of availability. Most head injuries are of a benign nature and require no treatment beyond analgesics such as acetaminophen. Non-steroidal painkillers such as ibuprofen are avoided since they could make any potential bleeding worse. Due to the high risk of even minor brain injuries, close monitoring for potential complications such as intracranial bleeding . If
12474-496: The outcome. Early work from Nikolai Bernstein worked to understand how coordination was developed in executing a skilled movement. In this work, he remarked that there was no one-to-one relationship between the desired movement and coordination patterns to execute that movement. This equivalence suggests that any desired action does not have a particular coordination of neurons, muscles, and kinematics. The complexity of motor coordination goes unnoticed in everyday tasks, such as in
12600-485: The person intends to drink from the glass, give it to someone else, or simply put it on a table. Inter-limb coordination is concerned about how movements are coordinated across limbs. In walking for instance, inter-limb coordination refers to the spatiotemporal patterns and kinematics associated with the movement of the legs. Prior work in vertebrates showed that distinct inter-limb coordination patterns, called gaits , occur at different walking speed ranges as to minimize
12726-410: The pressure by draining off the blood. Brain injury can occur at the site of impact, but can also be at the opposite side of the skull due to a contrecoup effect (the impact to the head can cause the brain to move within the skull, causing the brain to impact the interior of the skull opposite the head-impact). While impact on the brain at the same site of injury to the skull is the coup effect. If
12852-434: The result of a motor task, and good variability keeps the performance task unchanged and leads to a successful outcome. An interesting example of the good variability was observed in the movements of the tongue, which are responsible for the speech production. The stiffness level to the tongue's body creates some variability (in terms of the acoustical parameters of speech, such as formants), but this variability does not impair
12978-402: The return to school should be gradual and step-wise. Prolonged complete mental or physical rest (beyond 24–48 hours after the accident that lead to the concussion) may worsen outcomes, however, rushing back to full school work load before the person is ready, has also been associated with longer-lasting symptoms and an extended recovery time. Students with a suspected concussion are required to see
13104-410: The return-to-school transition including headaches, dizziness, vision problems, memory loss, difficulty concentrating, and abnormal behavior. Students must have completely resumed their school activities (without requiring concussion-related academic supports) before returning to full-contact or competitive sports. For persons participating in athletics, it is suggested that participants progress through
13230-411: The right visual field and the language areas (Broca's area and Wernicke's area). However, this does not mean someone with pure alexia is incapable of comprehending speech—merely that there is no connection between their working visual cortex and language areas—as is demonstrated by the fact that pure alexics can still write, speak, and even transcribe letters without understanding their meaning. Lesions to
13356-657: The risk of concussions among American Football players. Mouth guards have been put forward as a preventative measure, and there is mixed evidence supporting its use in preventing concussions but rather has support in preventing dental trauma. Educational interventions, such as handouts, videos, workshops, and lectures, can improve concussion knowledge of diverse groups, particularly youth athletes and coaches. Strong concussion knowledge may be associated with greater recognition of concussion symptoms, higher rates of concussion reporting behaviors, and reduced body checking-related penalties and injuries, thereby lowering risk of mTBI. Due to
13482-401: The risk of developing Alzheimer's disease later in life. Head injury may be associated with a neck injury. Bruises on the back or neck, neck pain, or pain radiating to the arms are signs of cervical spine injury and merit spinal immobilization via application of a cervical collar and possibly a longboard. If the neurological exam is normal this is reassuring. Reassessment is needed if there
13608-506: The risk of people becoming socially isolated. The person should work with their employer to design a step-wise "return-to-work" plan. For those with a high-risk job, medical clearance may be required before resuming an activity that could lead to another head injury. Students should have completed the full return-to-school progression with no academic accommodations related to the concussion required before starting to return to part-time work. The majority of children and adults fully recover from
13734-427: The rules or enforcing existing rules in sports, such as those against "head-down tackling", or "spearing", which is associated with a high injury rate, may also prevent concussions. Adults and children with a suspected concussion require a medical assessment with a doctor or nurse practitioner to confirm the diagnosis of concussion and rule out more serious head injuries. After life-threatening head injuries, injuries to
13860-499: The same high rate of favorable outcomes as concussions without convulsions. Cognitive symptoms include confusion, disorientation , and difficulty focusing attention . Loss of consciousness may occur, but is not necessarily correlated with the severity of the concussion if it is brief. Post-traumatic amnesia , in which events following the injury cannot be recalled, is a hallmark of concussions. Confusion may be present immediately or may develop over several minutes. A person may repeat
13986-452: The same questions, be slow to respond to questions or directions, have a vacant stare, or have slurred or incoherent speech. Other concussion symptoms include changes in sleeping patterns and difficulty with reasoning, concentrating, and performing everyday activities. A concussion can result in changes in mood including crankiness, loss of interest in favorite activities or items, tearfulness, and displays of emotion that are inappropriate to
14112-499: The same symptom severity. Repeated concussions may increase a person's risk in later life for dementia, Parkinson's disease, and depression. In post-concussion syndrome, symptoms do not resolve for weeks, months, or years after a concussion, and may occasionally be permanent. About 10% to 20% of people have persisting concussion symptoms for more than a month. Symptoms may include headaches, dizziness, fatigue, anxiety , memory and attention problems, sleep problems, and irritability. Rest,
14238-399: The severity of a brain injury. It is based on three traits: eye-opening, verbal response, and motor response, which are gauged as described below. Based on the Glasgow Coma Scale severity is classified as follows: There are several imaging techniques that can aid in diagnosing and assessing the extent of brain damage, including: CT scans and MRI are the two techniques widely used and are
14364-719: The severity of brain injuries are mild, moderate or severe. Symptoms of a mild brain injury include headaches, confusion, ringing ears, fatigue, changes in sleep patterns, mood or behavior. Other symptoms include trouble with memory, concentration, attention or thinking. Mental fatigue is a common debilitating experience and may not be linked by the patient to the original (minor) incident. Narcolepsy and sleep disorders are common misdiagnoses. Cognitive symptoms include confusion, aggression, abnormal behavior, slurred speech, and coma or other disorders of consciousness. Physical symptoms include headaches that do not go away or worsen, vomiting or nausea, convulsions or seizures, abnormal dilation of
14490-416: The situation. Common symptoms in concussed children include restlessness, lethargy, and irritability. The brain is surrounded by cerebrospinal fluid , which protects it from light trauma. More severe impacts, or the forces associated with rapid acceleration, may not be absorbed by this cushion. Concussions, and other head-related injuries , occur when external forces acting on the head are transferred to
14616-578: The skull and breaches the dura mater. Brain injuries may be diffuse , occurring over a wide area, or focal, located in a small, specific area. A head injury may cause skull fracture , which may or may not be associated with injury to the brain. Some patients may have linear or depressed skull fractures. If intracranial hemorrhage occurs, a hematoma within the skull can put pressure on the brain. Types of intracranial hemorrhage include subdural , subarachnoid , extradural , and intraparenchymal hematoma . Craniotomy surgeries are used in these cases to lessen
14742-433: The skull but outside of the brain tissue, falls into three subtypes: Cerebral contusion is bruising of the brain tissue. The piamater is not breached in contusion in contrary to lacerations. The majority of contusions occur in the frontal and temporal lobes . Complications may include cerebral edema and transtentorial herniation. The goal of treatment should be to treat the increased intracranial pressure . The prognosis
14868-496: The sodium-potassium ion pumps increase activity, which results in excessive ATP ( adenosine triphosphate ) consumption and glucose utilization, quickly depleting glucose stores within the cells. Simultaneously, inefficient oxidative metabolism leads to anaerobic metabolism of glucose and increased lactate accumulation. There is a resultant local acidosis in the brain and increased cell membrane permeability , leading to local swelling. After this increase in glucose metabolism, there
14994-458: The space of elemental variables (i.e. the rotations shared by the shoulder, elbow, and wrist in arm movements) and selects the feasible manifolds (i.e. sets of angular values corresponding to a final position). This hypothesis acknowledges that variability is always present in movement, and it categorizes it into two types: (1) bad variability and (2) good variability. Bad variability affects the important performance variable and causes large errors in
15120-638: The syndrome is due to structural damage or other factors such as psychological ones, or a combination of these, has long been the subject of debate. Head injury The number of new cases is 1.7 million in the United States each year, with about 3% of these incidents leading to death. Adults have head injuries more frequently than any age group resulting from falls, motor vehicle crashes, colliding or being struck by an object, or assaults. Children, however, may experience head injuries from accidental falls or intentional causes (such as being struck or shaken) leading to hospitalization. Acquired brain injury (ABI)
15246-415: The task of picking up and pouring a bottle of water into a glass. This seemingly simple task is actually composed of multiple complex tasks. For instance, this task requires the following: (1) properly reaching for the water bottle and then configuring the hand in a way that enables grasping the bottle. (2) applying the correct amount of grip force to grasp the bottle without crushing it. (3) coordinating
15372-402: The trajectory of an end-effector, such as a hand. An example of such concept is the minimum-jerk model proposed by Neville Hogan and Tamar Flash , which suggests that the parameter the nervous system controls is the spatial path of the hand, ensuring that it is maximally smooth. Francesco Lacquaniti , Carlo Terzuolo and Paolo Viviani showed that the angular velocity of a pen's tip varies with
15498-975: The treatment of brain injury. Prognosis, or the likely progress of a disorder, depends on the nature, location, and cause of the brain damage (see Traumatic brain injury , Focal and diffuse brain injury , Primary and secondary brain injury ). In children with uncomplicated minor head injuries the risk of intracranial bleeding over the next year is rare at 2 cases per 1 million. In some cases transient neurological disturbances may occur, lasting minutes to hours. Malignant post traumatic cerebral swelling can develop unexpectedly in stable patients after an injury, as can post-traumatic seizures . Recovery in children with neurologic deficits will vary. Children with neurologic deficits who improve daily are more likely to recover, while those who are vegetative for months are less likely to improve. Most patients without deficits have full recovery. However, persons who sustain head trauma resulting in unconsciousness for an hour or more have twice
15624-463: The two-thirds power of the path curvature (two-thirds power law ) during drawing and handwriting. The two-thirds power law is compatible with the minimum-jerk model, but also with central pattern generators . It has subsequently been shown that the central nervous system is devoted to its coding. Importantly, control strategies for goal directed movement are task-dependent. This was shown by testing two different conditions: (1) subjects moved cursor in
15750-795: Was paving way for a new railroad line when he encountered an accidental explosion of a tamping iron straight through his frontal lobe. Gage observed to be intellectually unaffected but exemplified post-injury behavioral deficits. These deficits include: becoming sporadic, disrespectful, extremely profane, and gave no regard for other workers. Gage started having seizures in February 1860, dying only four months later on May 21, 1860. Ten years later, Paul Broca examined two patients exhibiting impaired speech due to frontal lobe injuries. Broca's first patient lacked productive speech. He saw this as an opportunity to address language localization. It wasn't until Leborgne, formally known as "tan", died when Broca confirmed
15876-648: Was proven fact. Head injury is the leading cause of death in many countries. Motor coordination In physiology , motor coordination is the orchestrated movement of multiple body parts as required to accomplish intended actions , like walking. This coordination is achieved by adjusting kinematic and kinetic parameters associated with each body part involved in the intended movement. The modifications of these parameters typically relies on sensory feedback from one or more sensory modalities (see multisensory integration ), such as proprioception and vision . Goal-directed and coordinated movement of body parts
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