Intellectual function following penetrating head injury in Vietnam veterans.

The extent to which intellectual processes are preserved as a function of preinjury 'intelligence' and of size and location of the brain lesions was evaluated in Vietnam war veterans who survived penetrating missile wounds. With regard to an overall postinjury intelligence test score, preinjury intelligence was most predictive, size of lesion was next most predictive and lesion location was least important. For subtest scores from the same intelligence test, lesion location assumed much greater predictive value. Specifically, left temporal and occipital lesions impaired performance on subtests assessing vocabulary and object-function matching ability.

Clinical and radiological correlates of somatosensory evoked potentials in the late phase of head injury: a study of 500 Vietnam veterans.

Somatosensory evoked potentials were obtained after median nerve stimulation in 500 Vietnam veterans surviving penetrating head wounds 12-16 years earlier and 76 age-matched, uninjured controls. The results were studied in relation to neurologic history and findings, anatomical data provided by CT scan, and information derived from electroencephalograms. Thirty-five percent of head-injured individuals had abnormal SEPs and 76% of SEP abnormalities consisted of absence of N20 or N20/P25 complex. SEP abnormality correlated (P greater than 0.001) with the extent of total brain volume loss, sensory deficits (especially position and cortical discriminatory modalities), hemiparesis, organic mental disorder, CT evidence of parietal or thalamic injury, and centro-parietal EEG abnormalities. Recovery from hemiparesis was correlative with patients who subsequently had normal SEPs.

The effects of lateralized frontal lesions on mood regulation.

A group of Vietnam veterans with penetrating brain wounds to the orbitofrontal, dorsofrontal, and nonfrontal cortex were compared with a stratified control group of self-report and observed measures of mood state and cognition. In particular, hypotheses regarding the regulation of anxiety by frontal cortical mechanisms were evaluated. Results indicated that patients with right orbitofrontal lesions were prone to abnormally increased 'edginess'/anxiety and depression, whereas patients with left dorsofrontal lesions were prone to abnormally increased anger/hostility. A working model of mood state regulation is presented which represents the thesis that mood sensations are subject to numerous cognitive and biological influences that result in a variety of expressions of a particular mood disorder.

Predicting posttraumatic epilepsy in penetrating head injury.

Using data derived from a 15-year follow-up study of 520 veterans surviving penetrating brain wounds received in the Vietnam war, we have developed a predictive formula and tables for posttraumatic epilepsy based on time elapsed postinjury and presence of specific clinical and computed tomographic scan risk factors. Such patients remain at some increased risk for epilepsy even ten to 15 years postinjury, although most can be 95% certain of avoiding epilepsy if they have been seizure free for three years posttrauma. Epilepsy onset latency was independent of any risk factors identified.

Penetrating war injuries of the basal forebrain: neurology and cognition.

We compared the neurologic and cognitive performance of 15 young veterans who suffered unilateral penetrating missile wounds to the basal forebrain 15 years ago in the Vietnam War with uninjured controls and patients with lesions elsewhere in the brain. The subjects performed worse on tests of episodic memory, reasoning, and arithmetic and had more prolonged unconsciousness after injury; but their performance usually compared favorably with that of uninjured controls on tests of intelligence, attention, and language and was not consistent with that of a demented patient. The data suggest that the basal forebrain is functionally related to the reticular formation and to the basal forebrain is functionally related to the reticular formation and to the limbic-hippocampal memory system.

Consciousness and amnesia after penetrating head injury: neurology and anatomy.

Among 342 men who survived severe penetrating brain wounds, only 15% had prolonged unconsciousness and 53% had no or momentary unconsciousness after injury, emphasizing the focal nature of these wounds. The left (or language-dominant) hemisphere was dominant for the "wakefulness" component of consciousness. The areas most associated with unconsciousness included the posterior limb of the left internal capsule, left basal forebrain, midbrain, and hypothalamus. Left dominance was not seen for posttraumatic amnesia after elimination of the wakefulness variable, suggesting that wakefulness may be linked to the role of the left hemisphere in verbal memory.

Isolated impairment of memory following a penetrating lesion of the fornix cerebri.

Persistent memory problems were reported by a 39-year-old man who suffered a penetrating brain wound while serving in Vietnam 15 years earlier. Neuropsychological testing indicated an unusually isolated memory impairment. Computed tomography revealed transection of the columns of the fornix cerebri with no temporal-lobe involvement and minimal thalamic damage. We suggest that the fornix cerebri has a role in the maintenance of information accessibility to both encoding and recall during post-working memory processing and in the organization of verbal information during encoding and/or retrieval for declarative (recall) purposes. These processes are not essential for verbal recognition but can result in decrements on specific laboratory tasks and in social adjustment.

Epilepsy after penetrating head injury. I. Clinical correlates: a report of the Vietnam Head Injury Study.

Of 421 veterans who had penetrating brain wounds in Vietnam 15 years ago, 53% had posttraumatic epilepsy, and one-half of those still had seizures 15 years after injury. The relative risk of developing epilepsy dropped from about 580 times higher than the general age-matched population in the first year to 25 times higher after 10 years. Patients with focal neurologic signs or large lesions had increased risk of epilepsy, and site of the lesion may have been more important than size in determining occurrence. Family history of epilepsy or preinjury intelligence had no effect on seizure occurrence. Seizure frequency in the first year predicted future severity of seizures. Phenytoin therapy in the first year after injury did not prevent later seizures.

Effects of left-hand preference on postinjury measures of distal motor ability.

The relationship of preinjury left-hand dominance for motor performance to postinjury distal motor skills following penetrating brain wounds in patients without overt hemiplegia was examined. We studied 13 controls, 13 right-hemisphere brain-damaged patients, and 11 left-hemisphere brain-damaged patients on motor tasks measuring reaction time, strength, and coordination. Our results indicated that no persistent deficits were seen on distal motor tasks in left-handed adults who suffered a penetrating brain wound. These findings are compatible with the relative sparing of persistent neuropsychological deficits in left-handers following brain damage.