A Small 8-Electrode Electrical impedance Measurement Device for Urine Volume Estimation in the Bladder

Urinary incontinence is prevalent among elderly people. Recent studies have demonstrated the effectiveness of continence care based on urine volume measurement for elderly people who maintain their urinary storage function, but have difficulty feeling bladder fullness owing to dementia or neurological disorders. Electrical impedance measurement is a feasible technique that can be adopted in the diaper or underwear for continuous and unobtrusive urine volume measurements. We developed a small sensor device that can measure electrical impedance with a resolution of 0.017 Omega, which is sufficiently small to capture abdominal impedance alterations triggered by urine accumulation. The results obtained from a preliminary feasibility test in a young healthy volunteer suggested that the 8-electrode electrical impedance measurement with linear regression can estimate urine volume in the bladder in humans for the first time.