Chapter 4 - Penetrating head injury

Abstract

This chapter reviews penetrating head injury, which may cause brain lesion characterized by a more focal damage and the absence of a favored loci. The effects of a penetrating head injury can be variable, depending on the nature of the injury itself. Patients with cerebral missile wounds, especially where the missile is of low velocity, represent an ideal sample for the detection and elucidation of focal memory deficits; hemispheric asymmetry of memory function is clearly illustrated by such findings. When studying verbal memory deficits, it has been observed that patients with lesions involving the left parietal and occipital regions are particularly impaired on verbal paired-associate learning and nonsense syllable learning tests, whereas patients with left temporoparietal injury perform poorly on tests of memory span for verbal material and a test of letter recall after a short delay. As in the case of verbal memory tests, in the case of nonverbal deficit tests, neither depth of lesion nor amount of tissue loss showed any relationship to level of impairment on the maze learning task. Patients with penetrating head injury who display both verbal and nonverbal memory deficits have usually incurred bilateral or multifocal lesions. In some cases, the relevant lesions would have involved the diencephalic region, and in those patients who survive such an injury, there may often be deficits related to both subcortical and cortical damage, each of which may, in turn, vary according to the precise trajectory of the missile.