Hippocampal volume, early cognitive decline and gait variability: which association?

BACKGROUND: In contrast to its prominent function in cognition, the involvement of the hippocampus in gait control is still a matter of debate. The present study aimed to examine the association of the hippocampal volume with mean values and coefficients of variation (CoV) of spatio-temporal gait parameters among cognitively healthy individuals (CHI) and patients with mild cognitive impairment (MCI).

METHODS: A total of 90 individuals (47 CHI with a mean age of 69.7±3.6years and 48.9% women, and 43 MCI individuals with a mean age of 70.2±3.7years and 62.8% women) were included in this cross-sectional study. The hippocampal volume was quantified from a three-dimensional T1-weighted MRI using semi-automated software. Mean values and CoV of stride time, swing time and stride width were measured at self-selected pace with a 10m electronic portable walkway (GAITRite®). Age, gender, body mass index, number of drugs daily taken, Mini-Mental State Examination (MMSE) score, history of falls, walking speed and white matter signal-intensity abnormality scoring with Manolio scale were used as covariates.

RESULTS: Patients with MCI had a lower MMSE score (P<0.001), a higher CoV of stride time (P=0.013) and a lower hippocampal volume (P=0.007) compared with CHI. Multiple linear regression models showed that CoV of stride time was specifically associated with higher hippocampal volume among CHI (P<0.05) but not among patients with MCI (P>0.650).

CONCLUSIONS: Our findings revealed a positive association between a greater (i.e., better morphological structure) hippocampal volume and a greater (i.e., worse performance) stride time variability among CHI, but not among MCI individuals.