Specific Attentional Disorders and Freezing of Gait in Parkinson's Disease.

BACKGROUND Due to its high prevalence in dual-task paradigms, freezing of gait in Parkinson's disease is thought to be associated with dysexecutive syndrome and attentional disorders. However, the role of specific attentional disorders in patients with freezing of gait is still unclear. OBJECTIVE Here, we sought to specifically determine which basic attentional modalities are impaired in patients with freezing of gait. METHODS Seventy-eight parkinsonian patients performed a computer-controlled reaction-time paradigm designed to measure the different attentional subcomponents, controlled for visuospatial processing and motor participation. RESULTS The freezer (n = 42) and non-freezer (n = 36) groups were matched for age, educational level, MMSE and Mattis Dementia Rating Scale. There were no intergroup differences in simple reaction times, whereas choice reaction times were higher in the freezer group than in the non-freezer group for divided attention (p = 0.023). CONCLUSIONS At equivalent levels of overall cognitive efficiency, freezer patients showed a greater slowdown than non-freezer patients with a specific impairment in divided attention.