Neuropsychological interpretation of visuospatial and psychomotor disorders after cerebellar ischaemic stroke

Introduction
The role of the cerebellum in psychological functioning has been under debate. Cerebellar stroke is uncommon, but may result in various neurocognitive complications.

Aim
The present study intends to investigate selected aspects of neuropsychological functioning (i.e. visuospatial and psychomotor abilities) of patients with selective cerebellar lesions and to evaluate the significance of laterality in cognitive symptoms.

Material and methods
Fourteen patients (3 women and 11 men) with stroke-induced infarctions limited only to the left or right cerebellar hemisphere (7 left- and 7 right-sided cerebellar lesions, respectively) as verified by neuroradiological findings underwent a neuropsychological assessment at the acute stage (no more than 30 days following their stroke). Their performance was compared with 28 demographically matched normal controls (NC). Subjects were assessed with the Rey-Osterrieth Complex Figure Test (CFT) and the Polish adaptation of the Finger Tapping Test (FTT). Standardized scores (z-scores) for each patient were calculated from the raw test scores. Transformation was conducted based on means and standard deviations values from NC.

Results
The majority of the patients manifested visuospatial and/or psychomotor impairments with varying degrees of severity. However, no visual memory problems were observed since the delayed recall trial on the CFT was normal in contrast to the copy trial. A significant predictor of specific symptoms was localisation of cerebellar lesions. Patients with left cerebellar lesions were slow on the FTT (both left and right hands) only, whereas those with right cerebellar stroke performed significantly worse on both motor (i.e. tapping – FTT) and visuospatial (CFT – copy trial) tests.

Conclusions
Cerebellar stroke may result in heterogeneous cognitive difficulties, including psychomotor slowness and impairment of visuospatial perception, which contrast with sparing memory.