Editing Head injury (section)

==Signs and symptoms==
Three categories used for classifying the severity of brain injuries are mild, moderate or severe.

=== Mild brain injuries ===
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.{{citation needed|date=October 2020}}

=== Moderate/severe brain injuries ===
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 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 deficit]]s, [[delusion]]s (often, to be specific, [[monothematic delusion]]s), 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]].<ref name=":5">{{cite journal | vauthors = Meschia JF | title = Traumatic brain injury and stroke | journal = Mayo Clinic Proceedings | volume = 89 | issue = 2 | pages = 142–3 | date = February 2014 | pmid = 24485126 | doi = 10.1016/j.mayocp.2013.12.006 | doi-access = free }}</ref>

=== Symptoms in children ===
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.<ref name=":5" />

Presentation varies according to the injury. Some patients with head trauma stabilize and other patients deteriorate. A patient may present with or without [[Functional neurological deficit|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, [[seizure]]s, [[nausea]] and [[vomiting]], [[headache]] and a [[lucid interval]], during which a patient appears conscious only to deteriorate later.<ref name=":4">{{cite journal|last1=Atianzar|first1=Kimberly|last2=Casterella|first2=Peter|last3=Zhang|first3=Ming|last4=Sharma|first4=Rahul|last5=Gafoor|first5=Sameer|date=2017|title=Update on the Management of Patent Foramen Ovale in 2017: Indication for Closure and Literature Review|journal=US Cardiology Review|volume=11|issue=2|pages=75|doi=10.15420/usc.2017:18:1|issn=1758-3896|name-list-style=vanc|doi-access=free}}</ref>

Symptoms of skull fracture can include:
* leaking [[cerebrospinal fluid]] (a clear fluid drainage from [[Human nose|nose]], [[Human mouth|mouth]] or [[ear]]) is strongly indicative of [[basilar skull fracture]] and the tearing of sheaths surrounding the brain, which can lead to secondary brain [[infection]].
* visible deformity or depression in the head or face; for example a sunken eye can indicate a [[maxilla]]r fracture
* an eye that cannot move or is deviated to one side can indicate that a broken facial bone is pinching a [[nerve]] that innervates eye muscles
* [[wound]]s or bruises on the scalp or face.
* [[Basilar skull fracture]]s, those that occur at the base of the [[Human skull|skull]], are associated with [[Battle's sign]], a [[Subcutaneous tissue|subcutaneous]] bleed over the [[mastoid]], [[hemotympanum]], and [[cerebrospinal fluid]] [[rhinorrhea]] and [[otorrhea]].

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 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 a clinical setting given multiple factors about the patient—including mechanism/location of the injury, age of the patient, and GCS score.<ref name="pmid19758692">{{cite journal|author1-link=Nathan Kuppermann | vauthors = Kuppermann N, Holmes JF, Dayan PS, Hoyle JD, Atabaki SM, Holubkov R, Nadel FM, Monroe D, Stanley RM, Borgialli DA, Badawy MK, Schunk JE, Quayle KS, Mahajan P, Lichenstein R, Lillis KA, Tunik MG, Jacobs ES, Callahan JM, Gorelick MH, Glass TF, Lee LK, Bachman MC, Cooper A, Powell EC, Gerardi MJ, Melville KA, Muizelaar JP, Wisner DH, Zuspan SJ, Dean JM, Wootton-Gorges SL | display-authors = 6 | title = Identification of children at very low risk of clinically-important brain injuries after head trauma: a prospective cohort study | journal = Lancet | volume = 374 | issue = 9696 | pages = 1160–70 | date = October 2009 | pmid = 19758692 | doi = 10.1016/S0140-6736(09)61558-0 | s2cid = 43075627 }}</ref>

=== Location of brain damage predicts symptoms ===
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.<ref>{{Cite web |title=Traumatic brain injury - Symptoms and causes |url=https://www.mayoclinic.org/diseases-conditions/traumatic-brain-injury/symptoms-causes/syc-20378557 |access-date=2023-06-08 |website=Mayo Clinic |language=en}}</ref> Brain injuries often create impairment or [[disability]] that can vary greatly in severity.

Studies show there is a correlation between brain lesion and language, speech, and category-specific disorders. Wernicke's aphasia is associated with [[Anomic aphasia|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]].<ref>{{Cite web|url=https://dnalc.cshl.edu/|title=CSHL DNA Learning Center|website=dnalc.cshl.edu}}</ref><ref>{{cite book | doi=10.1007/978-0-387-79948-3_935 | chapter=Wernicke–Lichtheim Model of Aphasia | title=Encyclopedia of Clinical Neuropsychology | date=2011 | last1=Hux | first1=Karen | pages=2702–2703 | isbn=978-0-387-79947-6 }}</ref>

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 is indicative of damage to the posterior inferior frontal gyrus of the brain.<ref>{{Cite journal|last=Kean|first=Mary Louise | name-list-style = vanc | date = October 2003 |title=Syntactic deficits in aphasia: Was Wernicke right after all? |journal=Brain and Language|volume=87|issue=1|pages=27–28|doi=10.1016/s0093-934x(03)00180-9 |s2cid=54407724 }}</ref>

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 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.<ref>{{Cite journal|last=Wilkes|first=Kathleen V. | name-list-style = vanc |date= October 1980 |title=More Brain Lesions |journal=Philosophy|volume=55|issue=214|pages=455–470|doi=10.1017/s0031819100049482 |s2cid=170723313 }}</ref> Lesions to the [[fusiform gyrus]] often result in [[prosopagnosia]], the inability to distinguish faces and other complex objects from each other.<ref>{{cite journal | vauthors = Corrow SL, Dalrymple KA, Barton JJ | title = Prosopagnosia: current perspectives |journal = Eye and Brain| publisher = Eye Brain | date = 26 September 2016 |volume = 8|pages = 165–175|doi = 10.2147/EB.S92838| pmid = 28539812|pmc = 5398751 | doi-access = free }}</ref>{{medical citation needed|date=November 2017}}<ref>{{Cite web |title=Prosopagnosia |url=https://www.ninds.nih.gov/health-information/disorders/prosopagnosia |access-date=2023-06-08 |website=National Institute of Neurological Disorders and Stroke |language=en}}</ref> 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 the amygdala.<ref>{{Cite journal |last1=Diano |first1=Matteo |last2=Tamietto |first2=Marco |last3=Celeghin |first3=Alessia |last4=Weiskrantz |first4=Lawrence |last5=Tatu |first5=Mona-Karina |last6=Bagnis |first6=Arianna |last7=Duca |first7=Sergio |last8=Geminiani |first8=Giuliano |last9=Cauda |first9=Franco |last10=Costa |first10=Tommaso |date=2017-03-27 |title=Dynamic Changes in Amygdala Psychophysiological Connectivity Reveal Distinct Neural Networks for Facial Expressions of Basic Emotions |journal=Scientific Reports |language=en |volume=7 |issue=1 |pages=45260 |doi=10.1038/srep45260 |pmid=28345642 |issn=2045-2322|pmc=5366904 |bibcode=2017NatSR...745260D }}</ref>

Other lesions to the [[visual cortex]] have different effects depending on the location of the damage. Lesions to [[Visual cortex|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]].<ref>{{Cite journal|last=Celesia|first=Gastone G. | name-list-style = vanc | date = January 2010 |title=Visual Perception and Awareness |journal=Journal of Psychophysiology|volume=24|issue=2|pages=62–67|doi=10.1027/0269-8803/a000014 }}</ref> Lesions to [[Visual cortex|V4]] can cause [[color-blindness]],<ref>{{cite journal | vauthors = Jaeger W, Krastel H, Braun S | title = [Cerebral achromatopsia (symptoms, course, differential diagnosis and strategy of the study). I] | language = de | journal = Klinische Monatsblätter für Augenheilkunde | volume = 193 | issue = 6 | pages = 627–34 | date = December 1988 | pmid = 3265459 | doi = 10.1055/s-2008-1050309 | s2cid = 260195187 }}</ref> and bilateral lesions to [[Visual cortex|MT/V5]] can cause the loss of the ability to perceive motion.<ref>{{Cite journal |last1=Bridge |first1=Holly |last2=Hicks |first2=Stephen L. |last3=Xie |first3=Jingyi |last4=Okell |first4=Thomas W. |last5=Mannan |first5=Sabira |last6=Alexander |first6=Iona |last7=Cowey |first7=Alan |last8=Kennard |first8=Christopher |date=2010-12-01 |title=Visual activation of extra-striate cortex in the absence of V1 activation |journal=Neuropsychologia |language=en |volume=48 |issue=14 |pages=4148–4154 |doi=10.1016/j.neuropsychologia.2010.10.022 |pmid=20974160 |issn=0028-3932|pmc=2998000 }}</ref> Lesions to 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.