Urinary incontinence is a major source of suffering and cost in older women. The most common type, urge incontinence, is due to bladder spasm (detrusor overactivity) and represents a failure of bladder control. Despite developments in treatment, success rates have remained static for 40 years, and both therapeutic mechanisms and bladder control remain poorly understood. Functional magnetic resonance imaging (fMRI), unlike positron emission tomography, allows direct tracking of the rapid brain changes embodying control of the bladder. Our recent observations in non-geriatric subjects have revealed for the first time with fMRI the network of brain regions that responds to bladder filling. An entirely novel finding is that regional brain response to filling is weaker in those with poor bladder control, offering new insight into bladder control physiology, diagnosis and therapeutic targets. Before embarking however on a large study aimed at determining therapeutic mechanisms and improving treatment, it is essential to confirm these striking observations in a small group representative of the population of interest: potentially urge-incontinent elderly women. Consonant with our findings in younger adults, our hypothesis is that, among older women, poor bladder control (urge incontinence/detrusor overactivity) is associated with reduced neural response to bladder filling bilaterally in the thalamus/insula area of the brain. By careful assessment, 2 contrasting groups of women (> 60 y) will be established: one with good bladder control and one with urge incontinence. Both will undergo fMRI with simultaneous basic urodynamics using proven methods. Brain responses, including the differences between the 2 groups, will be examined by statistical parametric mapping. If the hypothesis is confirmed, we intend to study how treatment affects brain control by adding fMRI to a just funded RO1. Failure to confirm it would suggest that urge incontinence differs in old and young (with important therapeutic implications). In either case, the proposed project will shed new light on brain control of the bladder, suggest new diagnostic methods, and provide a crucial step in improving treatment of a morbid and intractable condition.
