Preserved cognitive processes in cerebellar degeneration.

Aspects of cognitive processing in patients with cerebellar degeneration (CD) were studied in order to examine the validity of recent findings that CD patients demonstrate deficits in visuospatial cognition and verbal-associative learning. Two groups of patients with CD were compared to stratified matched control groups on tests examining selective visual attention, visual spatial attention, mental rotation of geometric designs, and memory for the temporal order of words they were previously exposed to. CD patients performed similarly to their matched controls across all tasks.

Perceptual timing in cerebellar degeneration.

This study examined time perception in 12 patients with cerebellar degeneration (CD) and in 13 normal controls (NC). We used a time bisection procedure with four interval conditions (100-900 msec; 8-32 sec; 100-600 msec; 100-325 msec). Each subject's bisection point, discrimination ability (the Weber ratio) and precision (the inverse of the proportion of unexplained variance) was calculated for each condition.

No specific effects of caloric stimulation on the visual-imagery processes of normal subjects.

Recent research indicates that neglect can be temporarily, but only partially, ameliorated by activating the contralateral hemisphere via caloric stimulation and other techniques. In this study, we evaluated whether caloric stimulation could be used to manipulate visual-imagery processes in normal subjects. 11 normal subjects participated in a quantitative visual-imagery task while undergoing caloric stimulation.

Induction of a recall deficit by rapid-rate transcranial magnetic stimulation.

We used rapid-rate, repetitive transcranial magnetic stimulation (rTMS) for the noninvasive study of verbal recall. Five right-handed normal subjects were studied. Recall followed immediately after presentation of a 12-word list.