The central cause of overactive bladder, a pilot study

Micturition is a complex process with interaction between the central and
peripheral nervous system on one hand and the bladder and urethra on the other
hand. It is a well balanced co-ordination between contraction of the detrusor
and relaxation of the urethral sphincter. This process, according to Holstege,
is controlled by a spinal-brainstem-spinal reflex system in which information
about bladder filling is continuously sent from the bladder, via the sacral
cord to the central part of the periaqueductal gray (PAG) in the midbrain.
Based on the bladder filling rate, certain cell groups in the lateral PAG can
activate the pontine micturition center (PMC). However, the PAG, in deciding
whether or not to activate the PMC, is strongly influenced by different regions
belonging to the limbic or emotional system, as well as by regions in the
prefrontal and orbitofronral cortex. All these regions continuously evaluate
the safety of the environment. In urge urinary incontinence these limbic system
or prefrontal cortical regions or their pathways to the PAG are dysfunctional
as a result of many small lesions caused by vascular or neurodegenerative
diseases.
At present most treatment modalities for OAB have their target in the bladder
wall. Antimuscarinic agents, the most frequently used therapy, reduce bladder
tone and increase bladder capacity during the filling phase. Other treatments
are behavioural therapy, pelvic floor muscle therapy, neuromodulation and
surgery. If the hypothesis that OAB in general is not a disease of the bladder
itself but of vascular or neurodegenerative brain disease is true, OAB should
be considered as a neurological disease that needs different therapies than
presently given.

The objective of this study is to proof the presence of lesions in the brain of
patients with overactive bladder and urge-incontinence (OAB wet) as a central
cause of this disorder. This survey is a pilot investigation for a larger study
on the central cause of overactive bladder and urge-incontinence.

An observational pilot study in 5 women and 5 men with overactive bladder and
urge-incontinence (OAB wet) and 5 volunteers (male/female) without any sign of
OAB or incontinence. In this study we will look by means of MRI scanning for
white matter lesions in the brain.

Patients and volunteers have to visit the outpatient clinic for an interview.
At home they have to fill in three questionnaires, and record a voiding diary
during 3 days. At a second visit a MRI scan will be made. Intravenous contrast
solution will not be used. Scanning time will be approximately 30 minutes. We
expect to find white matter lesions. In case of unsuspected disorders found on
MRI scanning such as meningiomas or aneurysms which need further evaluation and
treatment, the general practitioner will be informed.
SAFETY
The risk for the participants is very low. There is no medication involved in
the protocol. All investigations are non-invasive.