Asymmetrical cognitive differences associated with hemiparkinsonism

Abstract

The question of whether Parkinson's disease (PD) patients who have left (LPD) or right (RPD) motor predominance also exhibit cognitive differences is controversial. We examined this issue using a neuropsychological battery designed to provide a balanced sampling of both right- and left-hemispheric functions. RPD patients were impaired relative to LPD patients on verbally mediated tasks (left hemisphere function), but there was no group difference for visuospatial tasks (right-hemispheric function). In addition, there was a significant correlation between the extent of right side motor predominance and performance on verbal tasks, but there was no relationship between left side motor symptoms and performance on visuospatial tasks. The controversy related to cognitive differences in hemiparkinsonism may be due to the balance of the assessment procedure, the severity of motor asymmetry, or both.

Neuropsychological characteristics of parkinsonian patients with lateralized motor impairment

“…Also, among patients affected by stroke, cognitive impairment seems to be more frequently associated with infarctions in the arterial territories of the left hemisphere (Tatemichi et al, 1994). Although it has been suggested that right and left PD may have differing effects on behaviour (Barber et al, 1985;Fleminger, 1991) and cognition (Bentin et al, 1981;Direnfeld et al, 1984), the influence of motor asymmetry on the pattern of neuropsychological performances still largely remains uncertain (Direnfeld et al, 1984;Bowen et al, 1972;Bentin et al, 1981;Villardita et al, 1983;Boller et al, 1984;Chouza et al, 1984;Yochochi et al, 1985;Taylor et al, 1986;Oyebode et al, 1986;Starkstein et al, 1987;Spicer et al, 1988;Huber et al, 1989aHuber et al, , 1992Blonder et al, 1989;Reid et al, 1989;Agniel et al, 1991;Mohr et al, 1992;Tomer et al, 1993;Viitanen et al, 1994). Furthermore, there is very little information about the predictive value of initial extrapyramidal lateralization as it relates to the appearance of dementia (Direnfeld et al, 1984).…”

Motor asymmetry and substantia nigra volume are related to spatial delayed response performance in Parkinson disease

“…A number of studies fully or partially support the expected pattern of lateralized cognitive deficits: PD participants with worse left-sided motor dysfunction perform more poorly on visuospatial (right hemisphere) tasks and those with worse right-sided motor dysfunction perform more poorly on verbally mediated (left-hemisphere) tasks (Amick, Grace, & Chou, 2006;Blonder, Gur, Gur, Saykin, & Hurtig, 1989;Huber, Miller, Bohaska, Christy, & Bornstein, 1992;Spicer, Roberts, & LeWitt, 1988;Starkstein, Leiguarda, Gershanik, & Berthier, 1987;Taylor, Saint-Cyr, & Lang, 1986). Others found widespread cognitive deficits in participants with worse left-sided dysfunction while participants with worse rightsided dysfunction were relatively cognitively spared (Direnfeld et al, 1984;Tomer, Levin, & Weiner, 1993).…”

“…Additionally, researchers used different scales for measuring motor deficits and based group inclusion criteria on different aspects of asymmetry, which may contribute to the controversy. For example, some investigators chose to categorize participants according to initial side of symptom onset (Amick et al, 2006;Katzen, Levin, & Weiner, 2006;Tomer et al, 1993) while others used current ratings of absolute motor asymmetry (Barber et al, 1985;Blonder et al, 1989;Riklan et al, 1990); relatively little attention has been paid to the degree of motor asymmetry at the time of cognitive testing (Huber et al, 1992;Tomer et al, 1993).…”

Parkinson's disease treatments: focus on transcranial direct current stimulation (tDCS)

“…Indeed, the side of onset may have prognostic implications. 86 Moreover, cognitive decline in PD has been associated with left-sided onset of motor features, 87 hinting at an association between laterality of symptom onset and disease progression and severity. Further work is required to better characterize the role of lateralization in PD and possible associated effects of handedness upon disease onset and progression.…”