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Cognitive deficits are a common consequence of acute traumatic brain injury (TBI), even at the lowest level of injury severity: concussion and mild TBI (mTBI). Approximately 65% of patients with moderate to severe TBI report long-term problems with cognitive functioning, and as many as 15% of patients with mTBI have persistent problems, which often include cognitive deficits.
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Deficit leads to disability when it interferes with patients’ functional status (ie, their ability to perform their usual
Cognitive Sequelae of Traumatic Brain Injury
Section snippets
Key points
Short-Term Cognitive Impairment
Impaired consciousness and posttraumatic amnesia (PTA) are neurobehavioral hallmarks of acute TBI. According to consensus definitions, moderate and severe TBI are characterized by loss of consciousness for longer than 30 minutes and/or PTA persisting for at least 24 hours. PTA is the transitory period of disorientation, confusion, and amnesia following TBI which leaves a gap in memory. Patients in PTA also commonly experience disturbed sleep-wake cycle, decreased daytime arousal, agitation,
Deficits of executive function and everyday thinking skills
Executive functioning deficits are common following TBI, even among those with mild injuries. The term “executive function” describes a variety of high-order cognitive abilities predominantly subserved by regions in the prefrontal cortex and their circuitry. Deficits of the executive system threaten an individual’s ability to engage successfully in independent goal-oriented behavior. These functions are critically important for quality of life, as they are implicated in job performance, social
Pathophysiology of cognitive deficits following TBI
Closed head TBI occurs when the brain undergoes rapid acceleration-deceleration forces, which may involve blunt head impacts. However, rapid acceleration or deceleration of the head can occur without impact. The resultant biomechanical forces can include both translational (the head moving in a straight line with the brain’s center of gravity) and rotational (the brain rotating around its center of gravity) accelerations. Although there is great heterogeneity in the biomechanical profile of
Neuropsychological assessment
Cognitive functioning should be assessed in any patient with TBI. Interviewing the patient and a caregiver is recommended because a subgroup of patients with severe TBI has poor awareness of the presence or extent of their cognitive deficits and behavioral sequelae. An interview can evaluate the accuracy of the patient’s insight concerning their condition by asking them to appraise their memory for events and names of people from 1 day to another, plans for return to work or school,
Treatment
Rehabilitation is a broad health care field primarily concerned with reducing patients’ disability and enabling their independent functioning following a disease or injury. Rehabilitation for a physical disability, such as paralysis, might include physical exercises, assistive technology, and skill training, as well as social services. Cognitive rehabilitation therapy (CRT) is a term that describes treatments designed to improve patients’ participation in cognitive demanding activities, either
Summary
Cognitive deficits are common following TBI and contribute significantly to disability. The frontal lobes and their related circuitry are particularly vulnerable to traumatic damage; hence, executive dysfunction is prevalent. Impairments in executive dysfunction can profoundly impact patients’ quality of life, as these cognitive skills are implicated in job performance, social relationships, and activities of daily living. A neuropsychological evaluation provides a comprehensive assessment of
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This research was supported by Mild Traumatic Brain Injury and Diffuse Axonal Injury. NINDS Grant P01 NS056202 awarded to Douglas Smith, MD, and Neurobehavioral Outcome of Head Injury in Children. NINDS Grant NS-21889 awarded to Gerri Hanten, PhD, and Harvey Levin, PhD.