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Derek J Griffiths

Publications and source records attributed to Derek J Griffiths.

9 recordsLinked to original sources
PubMed2006

The impact of detrusor overactivity on bladder function in younger and older women.

PURPOSE: We examined the relationship of DO and aging, and bladder function in female volunteers. MATERIALS AND METHODS: We recruited 85 cognitively competent, fully functional female volunteers who were 22 to 90 years old (median age 54) with and without symptoms suggestive of DO. Comprehensive assessment included a bladder diary, uroflowmetry and videourodynamics. We examined predefined urodynamic and diary variables for associations with DO and age, summarizing results in the 3 subgroups no DO, intermediate DO and clinically relevant DO. RESULTS: Compared to women without DO those with DO showed a decrease in maximum cystometric capacity (558 vs 448 ml), mean daytime voided volume (260 vs 175 ml) and volume at strong desire to void (363 vs 283 ml) but an increase in maximum isovolumetric pressure (41 vs 64 cm H2O) and maximum detrusor pressure during involuntary contraction (intermediate and relevant DO 22 and 37 cm H2O, respectively). The positive association between increased detrusor contraction strength and DO was present at younger ages but absent in older subjects. Maximum urethral closure pressure and detrusor contraction strength decreased significantly with age. CONCLUSIONS: From young adulthood to old age DO appears to affect bladder function parameters. It is associated with decreased bladder capacity and increased bladder sensation. Moreover, in younger adults DO is also associated with increased detrusor contraction strength, which is an association not seen in older individuals. This age associated loss of muscle function may be related to sarcopenia, implying that different treatments may be appropriate in older adults.

Adult↗
PubMed2006

Omnibus permutation tests of the overall null hypothesis in datasets with many covariates.

Tests of the overall null hypothesis in datasets with one outcome variable and many covariates can be based on various methods to combine the p-values for univariate tests of association of each covariate with the outcome. The overall p-value is computed by permuting the outcome variable. We discuss the situations in which this approach is useful and provide several examples. We use simulations to investigate seven omnibus test statistics and find that the Anderson-Darling and Fisher's statistics are superior to the others.

Computer Simulation↗
PubMed2006

The effect of age on lower urinary tract function: a study in women.

OBJECTIVES: To identify age-associated changes in female lower urinary tract function across a wide age spectrum, controlling for detrusor overactivity (DO). DESIGN: Secondary analysis of a cross-sectional study of DO and aging. Eligible volunteers were stratified by age group and presence of DO. SETTING: Community-based volunteers, evaluated in research laboratory. PARTICIPANTS: Eighty-five ambulatory, nondemented, community-dwelling female volunteers, with and without bladder symptoms suggestive of DO, recruited by advertising, mean age 54 (range 22-90); 75% Caucasian, 21% African American. MEASUREMENTS: Comprehensive assessment included bladder diary, uroflowmetry, and detailed videourodynamics. Predefined urodynamic and diary variables were examined for association with age and DO. Mean values of these variables were calculated for subgroups aged 20 to 39, 40 to 59, and 60 and older (14 subjects > or =70). RESULTS: Maximum urethral closure pressure, detrusor contraction strength, and urine flow rate declined significantly with age (P<.001, P<.001, P=.006, respectively), regardless of whether DO was present. Most elderly individuals continued to empty their bladder almost completely, with normal voiding frequency. Mean number of nocturnal voids was less than one in all age groups. Bladder capacity did not decrease with age (mean 522 mL in oldest group) but was smaller in subjects with DO. Bladder sensation diminished significantly with age (P<.001) but was stronger in subjects with DO. CONCLUSION: Female bladder and urethral function appear to deteriorate throughout adult life, whether DO is present or not. Specifically, detrusor contractility, bladder sensation, and urethral pressure decline. The common belief that bladder capacity shrinks with age may be related to DO rather than to aging itself.

Adult↗
PubMed2005

Factors that distinguish continent from incontinent older adults with detrusor overactivity.

PURPOSE: In older adults detrusor overactivity (DO) is almost as common in continent individuals as in those with urge incontinence (UUI). Thus, UUI likely reflects the contribution of additional factors. We postulated that of functionally independent individuals in whom transient causes were excluded those in whom DO was accompanied by UUI would be more likely to have smaller functional bladder capacity, less warning and less ability to avert urine loss in the face of DO. MATERIALS AND METHODS: While blinded to continence status, we reviewed the records of all 52 cognitively intact and nonobstructed volunteers older than 65 years who had DO associated with urgency during urodynamic testing and had been asked to try to prevent leakage for 2 minutes. Of these individuals 31 were continent at home. RESULTS: In patients with UI mean functional bladder capacity +/- SD was smaller (313 +/- 153 vs 390 +/- 178 ml, p = 0.06) and warning was briefer (87 +/- 81 vs 120 +/- 116 ml), although the association with warning was less impressive (p = 0.14). The ability to forestall leakage for at least 2 minutes correlated strongly with being continent at home (p < 0.002). For continence detrusor suppression at the onset of DO was more important than sphincter contraction. CONCLUSIONS: Urge incontinence in older adults involves more than simply the presence of DO. Physical function, cognitive function and medications are already known to be important for continence. Our data suggest that functional bladder capacity and the ability to suppress involuntary contraction (and possibly warning) are also potentially important covariates. These factors may represent additional potential targets for behavioral and pharmacological therapy.

Age Factors↗
PubMed2004

Cerebral control of bladder function.

Symptoms such as overactive bladder represent disorders of bladder control. Functional brain scanning by positron emission tomography and functional magnetic resonance imaging suggest that normal control is exerted by a network of regions in the emotional nervous system, including periaqueductal gray, thalamus, insula, anterior cingulate, and prefrontal cortex. The network receives afferent signals, converts them to bladder sensations, and brings them to conscious attention, together with an unpleasant affect (desire to void) that motivates bladder emptying and thus maintains homeostasis. In patients with poor control, brain response to bladder filling differs; cerebral control is abnormal, even in the absence of involuntary detrusor contraction. Behavioral therapy and electrical stimulation appear to be possible treatments.

Brain↗
PubMed2002

Urge incontinence and impaired detrusor contractility in the elderly.

Among the elderly, both urge incontinence and elevated residual urine are common. When they occur together, they present a challenging clinical problem, called detrusor hyperactivity with impaired contractile function (DHIC). Impaired detrusor contractility has two aspects: elevated post-void residual urine volume and reduced detrusor contraction strength. Geriatric urge incontinence, especially in combination with reduced bladder sensation, is associated with specific cortical abnormalities: frontal and global cortical underperfusion and cognitive impairment. We have investigated, in 73 elderly incontinent patients, whether either aspect of impaired contractility is associated with urge incontinence, reduced sensation or these cortical abnormalities. For post-void residual urine, there are no significant associations. Detrusor contraction strength, however, is significantly increased (not impaired) if there is urge incontinence, reduced bladder sensation, or cortical underperfusion. Thus, DHIC appears to be a coincidental occurrence of two common conditions with different etiological factors.

Activities of Daily Living↗
PubMed2002

The pontine micturition centres.

OBJECTIVE: To review recent literature on the function of the two postulated pontine regions (the M- and L-regions) concerned with lower urinary tract control. MATERIAL AND METHODS: The work reviewed is based on stimulation and lesion experiments and post-operative follow-up in the cat, supported by acute chemical stimulation and blocking experiments in the rat and PET functional brain scanning in humans. RESULTS AND CONCLUSIONS: The M-region in the cat, homologous to Barrington's micturition centre and to a similar area in humans, is a small region both specific and necessary to voiding, the origin of the final common pathway to bladder and urethra, and the locus of co-ordination of the bladder and the striated sphincter. The L-region in the cat is part of a larger, less specific area that probably serves sphincter control in various circumstances, not exclusively micturition. The homolog of this region in the human or in the rat has not been adequately established.

Afferent Pathways↗