Gait patterns in Parkinsonian patients with or without mild cognitive impairment.

Although in recent years the relationship between cognition and gait in Parkinson's disease (PD) has received increasing attention, the specific connections between gait patterns and cognitive features are not fully understood. The objective of this study was to describe the gait patterns in patients affected by PD with or without mild cognitive impairment (MCI+ and MCI-, respectively). We also sought to find an association between gait patterns and specific cognitive profiles. Using a gait analysis system, we compared the gait patterns among MCI+ patients (n = 19), MCI- patients (n - 24), and age- and sex-matched healthy subjects (HS; n = 20) under the following conditions: (1) normal gait, (2) motor dual task, and (3) cognitive dual task. In PD patients, gait parameters were evaluated in both the off and on states. Memory, executive, and visuospatial domains were assessed using an extensive neuropsychological battery. Compared with MCI- PD and HS, MCI+ PD patients displayed reduced step length and swing time and impairment of measures of dynamic stability; these dysfunctions were only partially reversed by levodopa. We also found that dual-task conditions affected several walking parameters in MCI+ PD in the off and on states relative to MCI- PD and HS. Factor analysis revealed 2 independent factors, namely, pace and stability. The latter was strongly and directly correlated to the visuospatial domain. In conclusion, dysfunctions on specific gait parameters, which were poorly responsive to levodopa and highly sensitive to dual-task conditions, were associated with MCI in PD patients. Importantly, visuospatial impairment was strongly associated with the development of instability and more generally with the progression of PD.