Anomalies précliniques de la marche dans la maladie de Parkinson

Idiopathic Parkinsonu0027s disease (PD) has a long preclinical phase during which non-motor symptoms exist but are not specific. The aim of the study is to determine whether subtle gait disorders are prediagnostic markers of PD. Participants were selected from the Baltimore Longitudinal Study of Aging, including 10 prediagnostic PD (8M/2W) and thirty age-matched healthy controls. Prediagnostic PD were assessed for an average of 2.6 ± 1.3 years (range 1.0–5.3 years) before PD diagnosis with: clinical gait and balance assessment (i.e., 6-meter corridor walk at usual and maximal gait speed, semi-tandem stand, tandem stand, and one-leg stand), instrumental gait analysis (VICON ® ), upper-limb motor skills (i.e., Hand Rapid Alternating Movement Test, Finger Tapping Test, and Purdue Pegboard Test), neuropsychological assessment (i.e., processing speed, attention, executive functions, memory, language, and visuo-spatial skills), and non-motor symptoms (orthostatic hypotension, depression, sleep disorders, and urinary symptoms). Prediagnostic IPD showed slower gait speed due to shorter step length compared to controls. They also showed greater gait speed variability, which was correlated with falls. No statistically significant differences were found between the two groups for balance, upper-limb motor skills and non-motor symptoms. Prediagnostic PD showed lower visuospatial ability (Card Rotation Test) than controls. The set of variables that best discriminate between the two groups were age, clinical gait speed, Trail-Making Test Part B, and Card Rotation Test with 100% sensibility and 95.8% specificity. This is the first prospective longitudinal study demonstrating gait changes in prediagnostic idiopathic Parkinsonu0027s disease. Previous published studies have recruited high-risk population for PD, as asymptomatic carriers of LRRK2 mutation [1] or patients with rapid eye movement sleep behavior disorder [2,3] . Our findings could potentially be used as prediagnostic markers of IPD to identify those who could benefit from future neuroprotective therapy in order to delay, or even prevent, clinical manifestations.