Abstract
Two surveys of the population of the local mental hospital were carried out by the Amplitude-Averaging technique for A-scan echoencephalography. A total of twelve cases appeared to have shifted cerebral midline structures. Of these, ten were investigated further and four were thought to be cases of false positive error in patients with marked enlargement of the ventricular system from various causes.
The remaining six cases were thought to be correctly diagnosed by echoencephalography though this was proven in only three patients. Of the six patients believed to have displaced midlines, most if not all were due to unilateral atrophic disease rather than to space-occupying lesions.
The technique would not seem to be economically valuable for the investigation of resident mental hospital patients.