11 Attentional impairment in Multiple System Atrophy

Abstract

Background Several studies have reported cognitive impairment in the Parkinsonian (MSA-P) and cerebellar (MSA-C) variants of Multiple System Atrophy, particularly in executive functions. This is attributed to a dysfunction of the cognitive loop linking the prefrontal cortex to basal ganglia. Since a few studies have investigated attentional functions in MSA patients, we assessed cognitive dysfunction and different aspect of attention in patients with MSA-C and MSA-P. Methods Seventeen MSA patients underwent a cognitive assessment of verbal/visual memory, language, visuo-spatial abilities and executive functions. The patients and 32 matched controls were presented with an experimental attentional task designed on Posner’s original Attention Network Test. The task provided three cue conditions (no-cue, temporal-cue, spatial-cue), two target conditions (congruent/incongruent) and two cue validity manipulations (valid/invalid-cue). Comparing reaction times in different experimental conditions allowed assessing the efficiency of the three different attentional components: Alerting, Orienting and Executive Control. Results Patients with MSA-P were impaired in executive functions, verbal memory and visuo-spatial abilities; MSAC patients in space and object perception tasks. MSA patients performed significantly worse than controls in attentional tasks with MSA-C patients showing more errors and longer RTs in incongruent target conditions. Conclusions MSA patients show specific cognitive impairments. MSA-C patients, in particular, are impaired in the attentional tasks. The greater impairment of Executive Control in these patients may be attributed to the widespread degeneration of cerebellum and cerebello-ponto-thalamo fibres projecting to medial areas of prefrontal cortex.