Brain

ZAIDEL, DAHLIA, W.

doi: 10.1093/brain/109.3.547pmid: 3719290

Abstract SUMMARY Twenty-one patients with cerebrovascular lesions in posterior regions of the left or right cerebral hemispheres and nonfluent aphasics with damage in anterior regions of the left hemisphere were administered a specially designed multiple-object pictorial test which measured long-term memory for scenes depicting real world schemata versus jumbled unorganized scenes. The units in the pictures were familiar figures. Memory was tested separately for single details and for whole scenes. The results showed that within the left posterior group there was significantly poorer memory for unorganized relative to organized stimuli, especially for whole scenes. There was also a selective dissociation between the left and right posterior patients on the detail versus whole scene probes in the unorganized stimuli. At the same time, organized scenes depicting real world schemata were not selectively impaired in any of the patient groups. Further, the overall memory scores on the Memory for Pictorial Scenes Test obtained by the aphasic patients were not significantly lower than those obtained by the control subjects, while scores of both posterior groups were lower than the control group Taken together, the data suggest the following (1) Pictorial semantics, like linguistic semantics, are functions processed by the left posterior cortex. (2) While the posterior region in the left hemisphere plays a special role in remembering visual situational schemata that are newly encountered, familiar visual situational schemata may be bilaterally represented. This content is only available as a PDF. © Oxford University Press

EMSON, PIERS

doi: 10.1093/brain/109.3.582pmid: N/A

WILKINS, D. E.; HALLETT, M.; WESS, M. M.

doi: 10.1093/brain/109.3.561pmid: 3719291

The normal human audiogenic startle reflex is defined from a review of the literature, substantiated by a current investigation of normal subjects, and clarified pathophysiologically by a discussion of animal experimentation. The basic information is used to evaluate critically a variety of syndromes loosely termed ‘startle’ in the past. A new classification of startle syndromes is proposed.

SHORVON, SIMON

doi: 10.1093/brain/109.3.577pmid: N/A

OLSEN, T. SKYHØJ; BRUHN, P.; ÖBERG, R. G. E.

doi: 10.1093/brain/109.3.393pmid: 2424544

The study was designed to investigate whether aphasia in stroke patients with subcortical lesions (‘subcortical aphasia’) was due to the subcortical lesion itself or to dysfunction of cortical language zones. A consecutive series of 25 right-handed stroke patients with left hemisphere lesions verified by CT scanning were examined for aphasia in the acccute stage, and two weeks, three months and six months after the insult. Cerebral angiography, CT scan and regional cerebral blood flow (rCBF) measurements with the 133Xe intracarotid method were performed in the acute stage. The CT scan was repeated six months later.Seven patients had lesions which involved cortical structures. All of these were severely aphasic in the acute stage and six months later. The rCBF studies showed severe reduction of flow in the infarcts; the perfusion was incompatible with tissue viability. Eighteen patients had subcortical lesions. Eight of these were mildly to severely aphasic in the acute stat. Recovery was always excellent. Five patients recovered completely, while 3 showed only discrete (clinically undetectable) aphasia after six months. The rCBF demostrated low-flow areas in the cortex overlying the deep lesions, with a blood flow which was sufficient for tissue viability, but insufficient for normal tissue function (an ‘ischaemic penumbra’). The blood flow was pressure dependent (showing impaired autoregulation) in these low flow areas. Ten patients with subcortical lesions were not aphasic. Their CBF was normal.The subcortical lesions were permanent on CT scan while aphasia was transient in these patients as recovery was seen within three months. It was therefore unlikely that the subcortical lesions as such were the cause of aphasia. The present findings indicate that aphasia in patients with subcortical lesions may be due to hypoperfusion and fuctional loss in cortical language zones. The cortical low-flow areas were invariably confined to occluded vascular territories. These territories were kept viable by collateral circulation characterized by penumbbral flow and impaired autoregulation. The patients showed excellent recovery from aphasia. We suggest that the recovery of language is caused by spontaneous arterial recanalization or expansions of collaterals, giving rise to enhancement of flow in the hypoperfused cortical penumbra.

ANDERSON, MILNE

doi: 10.1093/brain/109.3.575pmid: N/A

doi: 10.1093/brain/109.3.583pmid: N/A

RAISMAN, G.

doi: 10.1093/brain/109.3.579-apmid: N/A

SEELEY, JOHN

doi: 10.1093/brain/109.3.581pmid: N/A

PLANT, GORDON T.; HESS, ROBERT F.; THOMAS, SIMON J.

doi: 10.1093/brain/109.3.469pmid: 3719286

The electroretinogram (ERG) and the occipital visual evoked potential (VEP) evoked by sinusoidal grating stimuli have been recorded in cases with a past history of optic neuritis. Although a significant reduction in pattern ERG amplitude was found in the patient group there was considerable overlap between the patient and the control populations The pattern ERG was not found to be a sensitive test in providing evidence of a previous attack of optic neuritis. Reduction in VEP amplitude was considerably greater than was the reduction in ERG amplitude. The residual visual deficit in the patients was quantified by measuring contrast sensitivity Overall, the greater the residual deficit the greater was the ERG abnormality, but in some individual patients it was found that the contrast sensitivity loss and the ERG amplitude reduction were not well correlated. No evidence was found for a latency change peripheral to the generators of the pattern ERG which might contribute to the VEP latency changes which occur following an attack of optic neuritis.