Poor balance control, lower nucleus accumbens volume in AD patients
Patients with Alzheimer’s disease (AD) have poor balance control potentially as a result of loss of volume in the nucleus accumbens, a recent observational study has shown.
The study included 107 AD patients (mean age 70.2±8.3 years) and 37 healthy controls (64.4±6.1 years). Exclusion criteria were a Mini Mental State Examination (MMSE) score of <10, conditions that affect posture and other types of dementia.
Neuropsychological parameters were assessed using the MMSE and the Seoul Neuropsychological Screening Battery (SNSB). Computerized dynamic posturography was used to quantitatively evaluate postural control.
Compared with controls, AD patients had significantly higher frequency of falls (1.49±1.92 vs 4.67±1.84; p<0.001) and mean sway velocity (1.14±0.31 vs 1.33±0.43; p<0.05), and lower mean time to fall (4.55±2.36 vs 3.02±2.17; p<0.05) during the eyes open (EO) condition.
Composite scores in the sensory organization test (SOT) were also significantly lower in the AD patients than in controls (74.73±7.80 vs 78.30±4.62; p<0.05).
Participants with fall frequency >3 had significantly lower putamen (p<0.05) and nucleus accumbens (p<0.001) volume, and lower verbal memory, visual memory, visuospatial function and frontal-executive function scores (p<0.001 for all) than those with fall frequency <4.
On the other hand, patients in the lower 50 percent of SOT composite scores had significantly lower hippocampus (p<0.05), thalamus (p<0.05) and nucleus accumbens (p<0.001) volumes, and lower verbal memory (p<0.05) and frontal-executive function (p=0.000) scores than those in the upper 50 percent of SOT composite scores.