Gait instability may be the first step towards risk of falling, exposure to dementia, and disability [1Montero-Odasso M. Gait and cognition: a complementary approach to understanding brain function and the risk of falling JAGS 2012 ;  60 : 2127-2136

Cliquez ici pour aller à la section Références]. Gait analysis under Single Task (ST) measures the locomotor capacity and quality; and under Dual Task (DT) the cognitive reserve.

Data were collected from an out-patients consultation dedicated to gait instability. A ST and DT (counting backwards one by one from fifty) gait analysis (Locometrix) was carried out for each patient. Under ST gait variables included: walking speed (m/s), cadence (Hz), cranio-caudal power (W), gait regularity (which measures the similarity of successive strides [dimensionless]). The dual task cost (DTC) was calculated for walking speed, cadence and regularity according to the formula: DTC (%)=100×(ST-DT)/ST.

One hundred and three patients were recruited (58F; 45M), age (76±7 years); BMI (25±4); MMS (26.5±3.3). Patients can be divided into 4 specific complaints: gait instability (n=46), recurrent falls (n=30); memory impairment (n=19) and senile gait (n=8). Gait analysis under ST provides information for gait analytic motor rehabilitation. Under DT conditions gait analysis: identifies cognitive involvement in gait disturbances, may explained recurrent falls, and helps to identify mild cognitive impairment subtypes (amnestic and non-amnestic). The DTC were 14.7±12.0%, 11.1±9.7%, 21.1±22% for walking speed, cadence and regularity respectively. There were no differences between genders, neither for each gait variable. From DTC specific motor phenotypes were identifying, and thus tailor motor-cognitive rehabilitation can be proposed; they may be in relation to specific physio-pathology mechanisms.

Gait analysis under ST and DT conditions seems to be part of a Gait Instability out-patients consultation in the elderly. These two measurements help to diagnosis, prognosis and tailor the motor-cognitive rehabilitation. Further cohort studies (patients and controls) have to be carried out for identification of DTC threshold for each gait variable.