Clinical studies of cerebral and urinary tract function in elderly people with urinary incontinence

Abstract

Brain and urinary tract function have been studied in a group of 128 geriatric patients with established urinary incontinence. Median age was 79 years. About half suffered from dementia. A group of 27 continent patients of similar age and cognitive status was used in some comparisons. It was expected that impaired voluntary control of voiding (urge incontinence) would be associated with particular aspects of cognitive impairment and dysfunction of specific regions of the brain. Comprehensive investigations, including 24 h monitoring of incontinence, videourodynamic testing, cognitive testing and SPECT brain scanning, demonstrated that genuine urge incontinence could be proven in half of the patients and was frequently accompanied by reduced sensation of bladder filling, especially in males. Genuine urge incontinence with reduced bladder filling sensation led to greater urine loss than other types of incontinence. Overall, cognitive function was slightly more impaired in patients with genuine urge incontinence, but the strongest and most specific association was with impaired temporal orientation. Genuine urge incontinence with reduced bladder filling sensation was associated with global underperfusion of the cerebral cortex and more specifically, with underperfusion of the frontal areas of the brain, especially on the right. These results are consistent with PET scan observations of Blok et al. (Brain 1997;20:112–121), which show that areas in the right anterior cingulate gyrus and right inferior frontal gyrus are involved in voluntary voiding of normal males.

Introduction

Urinary incontinence is common among the elderly. In some cases it may be due to acute causes such as a urinary infection or a recent stroke and is potentially transient. In others it may become established. This paper is concerned with established incontinence. The International Continence Society has defined four types of urinary incontinence—urge, genuine stress, reflex and overflow [7]. Urge incontinence, which is associated with overactive bladder function, is frequently observed in elderly patients. It represents a failure of voluntary control of the voiding reflex. Overactive bladder function may be of two different types—phasic detrusor instability or uninhibited overactive bladder [3]. Typically, during urodynamic testing of the uninhibited overactive bladder, there is no sensation of bladder filling nor any phasic bladder (detrusor) activity until, at a certain bladder volume, an involuntary detrusor contraction develops and urine leakage occurs. Among the elderly, if bladder function is overactive, it is frequently of the uninhibited overactive bladder type and is believed to be associated with cortical abnormalities [3]. Human and experimental observations have indicated some of the pathways and cerebral areas involved in voiding [8], but knowledge at levels above the pons and hypothalamus is incomplete. Recent positron emission tomography (PET) experiments [1]have shown that cerebral areas involved in normal voiding appear to be located predominantly on the right side, including areas in the right anterior cingulate gyrus and right inferior frontal gyrus.

We have examined brain and bladder function among incontinent geriatric patients undergoing rehabilitation in a tertiary centre. About half were demented according to conventional criteria. The hypothesis was that poor voluntary control of the bladder (urge incontinence) would be associated with particular aspects of cognitive impairment and with dysfunction of specific regions of the brain.