Printer Friendly

Cerebral aetiology of urinary urge incontinence in elderly people.

We have examined 73 elderly incontinent patients (mean age 79 years) and 27 continent subjects (mean age 78 years) of similar cognitive status. Among the incontinent patients, 20 were shown objectively to have urge incontinence with normal bladder filling sensation, 14 had objectively demonstrated urge incontinence with reduced bladder sensation, and 39 had other types of incontinence. We compared cognitive function (by Minimental State Examination: MMSE) and regional brain perfusion (by SPECT scanning) in these four groups.

Patients with objectively demonstrated urge incontinence and reduced bladder sensation stood out as being different from the rest: their mean MMSE score was significantly lower than that of any of the other three groups; perfusion of the frontal cortex was significantly poorer than that in the continent and other incontinent groups; global cortical perfusion was significantly poorer than in the other incontinence groups. This was not found in patients with urge incontinence and normal bladder sensation. The observations support the hypothesis that in elderly people urge incontinence with reduced bladder sensation can be a consequence of cortical neuropathy, especially in the frontal lobes.


Urge incontinence is the most common type in institutionalized elderly people (1). There is a striking uniformity in the urodynamic findings: as the bladder is filled, the detrusor remains inactive until a single involuntary detrusor contraction develops and leads to involuntary voiding. Often there is no sensation of bladder filling until the contraction is about to occur; in this case bladder filling sensation is reduced.

The abnormality underlying urge incontinence with reduced sensation has been named the uninhibited overactive bladder (2). In principle it might be idiopathic or secondary to urethral obstruction or to neuropathy (3). Among elderly people, dysfunction of brain regions concerned with the control of bladder and urethra (4)(5) might well be involved. We therefore examined a group of elderly people with urge incontinence with or without reduced sensation, seeking common patterns of cerebral dysfunction that cut across their various clinical diagnoses.

Ideally, to eliminate non-specific effects associated with ageing, cognitive impairment or concomitant disease, a reference group is required that is identical to the study group except for urge incontinence. Lacking such a group, we compared the findings with those among (a) incontinent elderly patients without demonstrable urge incontinence, and (b) continent patients, attending a memory clinic, of similar age and congnitive status. Both reference groups have limitations: (a) is heterogeneous; (b) may have its own disease-specific patterns of cerebral dysfunction.


Patients with established urinary incontinence were referred from a tertiary geriatric assessment and rehabilitation facility, after elimination of possible causes of transient incontinence (e.g. urinary infection, stroke within the preceding 12 months, acute confusion). Bedridden patients and those with an indwelling urethral catheter were excluded, and also any with overt subpontine neuropathy, multiple sclerosis or Parkinson's disease. After written informed consent had been obtained from the patient and if necessary from a close relative or guardian, physical examination, including a simple neurological examination, was performed. Patients with findings suggestive of peripheral neuropathy that might affect urinarytract function (abnormal sacral-dermatome, perineal or genital sensation; absent anal reflex; abnormal anal-sphincter tone) were excluded from further study. Drugs prescribed to influence bladder function were discontinued a week before the investigations. Other drugs judged necessary by the patient's physician were continued; their possible influence on incontinence has been discussed elsewhere (6).

Further study comprised: medical history, list of current medications, administration of an activities of daily living scale (7), voiding and incontinence history (supplemented by a caregiver if necessary); non-invasive 24-h monitoring of fluid intake, voids, incontinence and post-void residual urine (8); urinalysis, urine culture and sensitivity; video-urodynamic study of bladder filling, voiding and incontinence episodes. Single photon emission computed tomography (SPECT scanning) of the brain was performed, giving information about regional cerebral perfusion (9)(10). Cognitive assessment was carried out with the Mini-mental State Examination (MMSE) (11).

During 24-h monitoring, pre-weighed absorbent briefs ('pads') were worn; they were changed and reweighed regularly. Urine loss was assessed from the weight gain. Patients with a total pad weight gain of less than 10 g in 24 h, or with no pad with a weight gain of more than 2 g, were considered not to have demonstrated measurable urine loss (8) and were excluded from the rest of the study.

Video-urodynamic investigation was done in the supine and sitting positions. Methods and definitions followed the standards recommended by the International Continence Society (3) with the following exception. In these standards the term urge incontinence denotes a symptom or a sign, but there is no term for the corresponding condition, which (by analogy to the condition genuine stress incontinence) is urine loss occurring in the presence of an involuntary detrusor contraction, demonstrated urodynamically. Therefore we use the new term genuine urge incontinence for this condition.

During bladder filling, stress testing was performed by asking the patient to cough while recording intravesical, abdominal and detrusor pressures, the fluoroscopic appearance of the urethra and any leakage into a flowmeter. Patients were asked repeatedly about bladder sensation. Even cogitively impaired patients were able to give a clear answer. Filling was continued until there was a very strong desire to void, uninhibitible voiding occurred, or the detrusor pressure rose by more than 15 cm[H.sub.2]O. Genuine urge incontinence was diagnosed if actual leakage was detected during an involuntary detrusor contraction of any magnitude. Patients who failed to appreciate that their bladder was being filled, or felt it only just before or during a detrusor contraction associated with voiding, were classified as having reduced sensation of bladder filling. Possible urethral obstruction was judged from pressure and flow-rate measurements during voiding (12)(13). On the basis of this examination the incontinent patients were divided into three groups: those with genuine urge incontinence with either normal or reduced sensation, and the remainder with other incontinence (i.e. without demonstrable genuine urge incontinence).

A fourth group, containing continent subjects only, was formed by patients attending a geriatric memory clinic, after exclusion of any with a current history of urinary incontinence, acute confusion or pseudodementia. Their ages, sex ratio and cognitive impairment were similar to those of the incontinent patients. Thus there were finally four groups of patients: two study groups (genuine urge incontinence with either normal or reduced sensation) and two reference groups (other incontinence and continent). All incontinent patients had urine loss that had been objectively demonstrated during 24-h monitoring, while those in the continent group were all continent by history.

Single photon emission computed tomography (SPECT scanning) of the brain was performed for patients in these four groups, using 500 MBq of [sup.99m]Tc-labelled hexamethylpropyleneamine oxime, which was injected into a vein in the antecubital fossa (9). The filtered and reconstructed scan images were interpreted by a radiologist, experienced in this field, who was blinded to the other results of the study. His qualitative reports were coded for regional underperfusion in each of 14 brain regions, seven on each side (the superior and inferior frontal, parietal, occipital and temporal regions, the midbrain, and the cerebellum) and also for global underperfusion of the left and right cortical hemispheres. Underperfusion was coded as either absent or present; a few reports of regional overperfusion or of slight or questionable underperfusion were included in the 'absent' category.

Regional brain scan data for patients in the two study groups were examined: (a) for common regional patterns of abnormal perfusion; (b) for significant regional perfusion differences from the two reference groups. Differences between the groups in cognitive function (Mini-Mental State) were also examined.

Possible differences and associations were examined by nonparametric tests ([X.sup.2] and Mann-Whitney U test) where possible, and also by analysis of variance. Two-tailed significance levels were used, probabilities of less than 0.05 being defined as significant.


Incontinent patients: Seventy-three patients (44 women and 29 men) referred for incontinence were studied. Their mean age was 79 (range 60-98) years. Their score on the activities of daily living scale ranged from B to G with a median score of C, corresponding to impairment in one of the activities of daily living in addition to incontinence. Mini-Mental State Examination (MMSE) score ranged from 10/30 to 30/30 with a mean value of 22/30. Thirty-seven patients had an MMSE score below 24/30, which by convention indicates significant cognitive impairment. Twenty of the patients had a clinical diagnosis of possible primary degenerative dementia and 20 had possible multi-infarct dementia. These two diagnoses had similar frequencies in each of the three incontinent groups.

Video-urodynamic investigation demonstrated genuine urge incontinence in 34 of these 73 patients. Fourteen of the 34 had genuine urge incontinence with reduced bladder filling sensation and 20 had genuine urge incontinence with normal sensation. These formed the two study groups. The remaining 39 patients formed a heterogeneous reference group with genuine stress incontinence (5/39), incontinence of mixed or questionable type (7/39), overflow incontinence (1/39) or no objective leakage on video-urodynamics (with or without detrusor instability) (26/39).

Urine loss during 24-h monitoring, as judged from pad weight gain, ranged from 10 to 1512 g with a median value of 70 g. In the group with genuine urge incontinence and reduced sensation, urine loss was much greater than in the other two groups (Table I).

Table I. Measured urine loss in the three groups of incontinent patients (median and 25- and 75-percentiles)
                                           24-h urine
                                  No.      loss (g)
Reference group:
  Other incontinence              39        36 (18-144)
Study groups:
  Genuine urge incontinence
  + normal sensation              20        89 (26-157)
  + reduced sensation             14       346 (64-792)

Overall differences among the three groups are significant (p<0.0005) by analysis of variance.

There were significant differences in MMSE scores among the patient groups (Table II); in particular those having genuine urge incontinence with reduced sensation had a significantly lower score than any of the other groups. Genuine urge incontinence with normal sensation was not related to MMSE score.

Table II. Mini-mental state examination (MMSE) scores for the four patient groups (median and 25- and 75-percentiles)
                                  MMSE score
Reference groups:
  Continent                       24 (19-26)
  Other incontinence              24 (20-28)
Study groups:
  Genuine urge incontinence
  + normal sensation              24 (18-26)
  + reduced sensation             17(*) (15-22)

Overall, the differences among the four groups are significant (p = 0.02 by analysis of variance).

(*)Significantly different from continent group (p = 0.03), from non-urge incontinent group (p = 0.003) and from group with urge incontinence and normal sensation (p = 0.04), by Mann-Whitney U test.

A few of the incontinent men (6/29) showed evidence of urethral obstruction on urodynamics. In a separate study of the effects of transurethral resection of the prostate (14), we have shown that detrusor overactivity and urge incontinence are unlikely to be secondary to obstruction in these elderly patients. Thus urethral obstruction was not an important factor in the aetiology of the urge incontinence observed in this study.

Continent patients: The mean age of the 27 patients (17 women and 10 men) in the continent group was 78 (range 62-90) years. Their mean MMSE score was 22/30 (range 7-29/30). These figures are very similar to those for the 73 incontinent patients and do not differ from them significantly. In this group, all of whom had attended a memory clinic, the majority (82%) had a diagnosis of possible or probable primary degenerative dementia.

SPECT brain scan results: In all four groups some patients showed abnormalities of brain perfusion (Table III). [X.sup.2] tests demonstrated significant differences among the four groups in the right and left superior and right inferior frontal regions and in left global underperfusion.

In the group having genuine urge incontinence with reduced bladder filling sensation, underperfusion of the right superior frontal lobe was much more common than in any other group (Figure 1A), the differences being statistically significant (Table III). The left superior and right inferior frontal lobes showed similar but less pronounced differences.



Global underperfusion of left side of the cortex was common among those with genuine urge incontinence and reduced sensation, and significantly more common than among those with other incontinence (Table III and Figure 1B). Global underperfusion on the right side showed similar differences. However, global cortical underperfusion was also quite common among continent patients (Table III and Figure 1B).

Patients with genuine urge incontinence and normal sensation showed less marked regional perfusion anomalies (Table III and Figure 1A and B). There were no significant differences from either of the two reference groups.

Differences between men and women: Among incontinent women, the proportion with genuine urge incontinence and reduced sensation (3/44 = 7%) was significantly smaller than in men (11/29 = 38%, p = 0.003 by [X.sup.2]). Thus genuine urge incontinence with normal sensation was the predominant type among women. Underperfusion of the right superior and inferior frontal lobes was less common in women than in men (p = 0.01 by [X.sup.2] in both cases).


Fall and associates (2) have suggested that the uninhibited overactive bladder (which is the urodynamic abnormality underlying genuine urge incontinence with reduced bladder filling sensation) is an aetiologically distinct subclass of detrusor overactivity. Our results provide evidence that, among elderly people, cerebral neuropathy may be involved in its aetiology. Genuine urge incontinence with reduced sensation is associated not only with cognitive impairment, but also with global impairment of cortical perfusion and with regional underperfusion of the frontal lobes. Neither cognitive impairment nor global cortical underperfusion are specific for genuine urge incontinence with reduced sensation, as some continent elderly subjects also exhibit these characteristics. Therefore it is probable that dysfunction of specific brain structures is involved; our evidence suggests a location in the frontal lobes. This is consistent with the accepted view (4)(15) that voluntary control of voiding originates in the superior frontal gyrus/septal area of the superior frontal lobes and that lesions or degeneration there may lead to detrusor overactivity, urge incontinence and, if sufficiently extensive, reduced bladder sensation. It has been suggested that lesions in the midbrain (the basal ganglia) may also be involved in some types of detrusor overactivity (5) but, if so, our SPECT scanning was not sensitive enough to detect them.

For genuine urge incontinence with normal bladder filling sensation, an association with cerebral abnormalities is much less obvious: there is no significant association with cognitive impairment and no clear pattern of regional perfusion abnormality.

Genuine urge incontinence with reduced bladder filling sensation, which is the type of incontinence most clearly associated with cognitive impairment, is more common among incontinent elderly men (38%) than women (7%). This difference may account for Resnick and associates' finding (1) that urge incontinence is associated with cognitive impairment in men but not in women. The difference between the sexes appears to be related to a difference in the characteristic patterns of regional perfusion impairment.

Uninhibited overactive bladder is reported to be common, occurring in 70% of all elderly patients with detrusor overactivity on urodynamic examination (16). In our series, genuine urge incontinence with reduced bladder sensation could be identified in only about 20% of all elderly incontinent patients. Nevertheless, because this type of incontinence is responsible for the most severe urinary leakage, it is important to understand it. Our conclusion is that it may be a consequence of cortical neuropathy, especially in the frontal lobes. Even if no cure is available, this knowledge may help caregivers and health-care professionals to maintain a sympathetic attitude to the elderly with the disability.


This work was supported by the Alberta Heritage Foundation for Medical Research, grant number 7676. We are grateful to Diane Hendrick, Rose Merke, and the staff of unit 10-Y, Edmonton General Hospital for conducting the 24-hour monitoring; the staff of the Department of Nuclear Medicine, Cross Cancer Institute for performing the SPECT scans; Shelley McIvor for coding the SPECT scans; and Dr Mahmoud Al-Rimawi for reviewing patients' charts.


(1.)Resnick NM, Yalla SV, Laurino E. The pathophysiology of urinary incontinence among institutionalized elderly persons. N Engl J Med 1989;320:1-7.

(2.)Fall M, Ohlsson BL, Carlsson C-A. The neurogenic overactive bladder: classification based on urodynamics. Br J Urol 1989;64:368-73.

(3.)International Continence Society. Standardisation of terminology of lower urinary tract function. Neurourol Urodyn 1988;7:403-26.

(4.)Torrens M. Human physiology. In: Torrens M, Morrison JFB, eds. The physiology of the lower urinary tract. London: Springer-Verlag, 1987.

(5.)Kitada S, Ikei Y, Hasui Y, Yamaguchi T, Nishi S, Osada Y. Bladder function in elderly males with subclinical MRI lesions. Neurourol Urodyn 1991;10:436-7.

(6.)Gormley EA, Griffiths DJ, McCracken PN, Harrison GM. Polypharmacy and its effect on urinary incontinence in a geriatric population. Br J Urol 1993;71:265-9.

(7.)Katz S, Ford AB, Moskowitz RW, et al. Studies of illness in the aged: the index of ADL: a standardized measure of biological and social function. JAMA 1963;185:914-19.

(8.)Griffiths DJ, McCracken PN, Harrison GM, Gormely EA. Characteristics of urinary incontinence in elderly patients studied by 24-hour monitoring and urodynamic testing. Age Ageing 1992;21:195-201.

(9.)Hooper HR, McEwan AJ, Lentle BC, Hooper PM. Interactive three dimensional region of interest analysis of Tc-99m HMPAO SPECT brain images. J Nucl Med 1989;30:961.

(10.)Costa DC, Ell PJ, Burns A, Philpot M, Levy R. CBF tomograms with 99m Tc-HMPAO in patients with dementia (Alzheimer type and HIV) and Parkinson's disease: initial results. J Cereb Blood Flow Metab 1988; 8:S109-15.

(11.)Folstein MF, Folstein SE, McHugh PR. 'Mini-mental state': a practical method for grading the cognitive state of patients for the clinician. J Psychiatr Res 1975;12:189-98.

(12.)Abrams PH, Griffiths DJ. The assessment of prostatic obstruction from urodynamic measurements and from residual urine. Br J Urol 1979;51:129-34.

(13.)Griffiths DJ, Van Mastrigt R, Bosch R. Quantification of urethral resistance and bladder function during voiding, with special reference to the effects of prostate size reduction on urethral obstruction due to benign prostatic hypertrophy. Neurourol Urodyn 1989;8:17-27.

(14.)Gormley EA, Griffiths DJ, McCracken PN, Harrison GM. Effect of transurethral resection of the prostate on detrusor instability and urge incontinence in elderly males. Neurourol Urodyn 1993;12:445-53.

(15.)Morrison JFB. Bladder control: role of higher levels of the central nervous system. In: Torrens M, Morrison JFB, eds. The physiology of the lower urinary tract. London: Springer-Verlag, 1987.

(16.)Geirsson G, Fall M, Lindstrom S. Subtypes of overactive bladder in old age. Age Ageing 1993;22:125-31.

Received in revised form 20 October 1993
COPYRIGHT 1994 Oxford University Press
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 1994 Gale, Cengage Learning. All rights reserved.

Article Details
Printer friendly Cite/link Email Feedback
Author:Griffiths, Derek J.; McCracken, Peter N.; Harrison, Gloria M.; Gormley, E. Ann; Moore, Katherine; Ho
Publication:Age and Ageing
Date:May 1, 1994
Previous Article:Cost comparison of domiciliary and hospital-based stroke rehabilitation.
Next Article:Asymptomatic swallowing disorders in elderly patients with Parkinson's Disease: a description of findings on clinical examination and...

Terms of use | Privacy policy | Copyright © 2018 Farlex, Inc. | Feedback | For webmasters