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

• The hippocampus is a key human brain region involved in memorization and locomotion.
• Greater hippocampal volume was associated with greater stride time variability among cognitively healthy individuals.
• Hippocampus seems to be involved in the control of the rhythmic stepping mechanism in normal but not in pathological aging.

BackgroundIn 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).MethodsA total of 90 individuals (47 CHI with a mean age of 69.7 ± 3.6 years and 48.9% women, and 43 MCI individuals with a mean age of 70.2 ± 3.7 years 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 10 m 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.ResultsPatients 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).ConclusionsOur 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.