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SUMMARY Limb apraxia was investigated with standardised tests in 14 patients whose CT scan provided evidence of a vascular lesion confined to the left basal ganglia, or the thalamus, or both, and not involving the cortex or adjacent white matter. Five patients were severely impaired in imitating movements and pantomiming object use. Four of them also performed poorly when tested with real objects. In two patients the lesion was primarily thalamic and in three the lesion was primarily in the lenticular nucleus and the posterior limb of the internal capsule. Patients without apraxia generally had smaller injuries, but there were exceptions. Apraxia is currently conceived of as due to damage of cortical areas and their cortico-cortical connections, but the present data suggest that the model should be enlarged to include the deep nuclei and the pathways running through them.The introduction of CT examination in neurological practice has opened new avenues to the understanding of the anatomical basis of higher nervous function disorders. On the basis of CT results, it has been discovered that deep hemispheric structures, play a hitherto unsuspected role in the genesis of symptoms that were thought to be the province of the neocortex and the underlying white matter.Depending on the side of lesion, Aphasia`6 and unilateral neglect' 2 7-10 have been reported to result from damage restricted to the striatum, or the thalamus, or both, suggesting that the circuits subserving language and lateral attention must be enlarged to include these structures. No comparable evidence has hitherto been reported for apraxia, a condition traditionally attributed to the involvement of parietal and frontal cortical areas of the hemisphere dominant for speech and/or to the fibre bundles connecting them within the same hemisphere and through the corpus callosum with the premotor cortex of the contralateral hemisphere." -

Orienting and focusing of attention were assessed in 32 Parkinson's disease and 32 control subjects. No differences were found in the covert orienting of attention, suggesting that the Parkinson's disease subjects of the current study were not impaired in the ability to orient attention towards an expected source of stimulation. However, with the process of modulating the attentional focus or of managing more than one attentional task, dysfunction in Parkinson's disease subjects became apparent. The observed results are explained in terms of deficits in the relationship between task-related distribution of attentional resources and time efficiency of processing.

A case of spinal epidural haematoma diagnosed by means of Gadolinium-DTPA-enhanced MR imaging is described. The sensitivity of this recent technique is underlined.