Aged women with urinary incontinence (UI) have a higher risk of falling than aged women without UI.(1) UI may interfere with cortical gait control, as UI symptoms are associated with abnormal gait patterns in adult women. UI may provide distraction leading to a cognitive cost during walking. The aim of this study was two fold: Aims of the study: (1) establish whether the desire to urinate influences walking performance during dual-tasking and (2) determine the correlation between UI, walking performance and cognitive cost during gait in older women.

This is a cross-sectional, repeated measures, laboratory-based study. Women aged 65 or older were recruited through public advertisements in the community. This study has been approved by the research ethics committee (H21/150). All participants provided informed consent prior to data collection.

Sample size was estimated using the G*Power software (version 3.1; Franz Faul, University of Kiel, Kiel, Germany). A moderate effect size was adopted for dual-task effect (DTE) in all the studied tasks (dz = 0.55). Using a matched pairs model, power (β − 1) = 0.80, α = .05, a total of 22 participants was required. (2)

All participants completed a short questionnaire with sociodemographic factors and questionnaires related to UI and cognition status. 

Experimental conditions
Walking performance protocol: The walking performance was assessed by the timed up-and-go (TUG) test, measured in seconds. 
Dual-task protocol: Participants were required to perform the TUG test simultaneously with two separate secondary tasks: the motor Coin Transference test, and the cognitive Semantic Verbal Fluency test (SVF). For the Coin Transfer test, participants transferred ten 50 cent coins one at a time, with the dominant hand, using a specific apron from one pocket to the other. The number of coins transferred during dual-task test was recorded. For the Semantic Verbal Fluency test, participants were instructed to produce words beginning with F, A or S and the word production rate was measured as words produced per min. The number of words produced during dual-task test was recorded. 
Bladder conditions: All participants performed the dual-task protocol in two void conditions: no desire-to-void and desire-to-void. The Indevus urgency severity scale (IUSS) were used to assess the desire-to-void. The IUSS is a validated 4-point scale, developed to evaluate urinary urgency. A score of 0 out of 3 (NONE: no urgency) were considered as no desire-to-void. A score of 3 out of 5 (MODERATE: enough urgency discomfort that it interferes with or shortens your usual activity or tasks) were considered as desire‐to‐void. To achieve the desire-to-void condition, participants were given 500ml of water to drink. For this study, the no desire to void condition will be called “empty bladder”, and the desire to void condition will be called “full bladder”. 
In total, participants performed six trials (TUG baseline, TUG cognitive empty and full bladder and TUG motor empty and full bladder). The trials were conducted in a pseudo-random order to avoid practice effects in the TUG test and secondary tasks.
 
Outcome measures
Primary outcome measures: (1) time to perform the TUG test (in seconds) and (2) dual-task effect (DTE). DTE was obtained considering the impact of secondary task (motor or cognitive) on TUG test performance  and was quantified by calculating the relative dual-task effect (DTE) using the following formula: DTE (%) = [-(dual-task – single-task) / single-task] x 100. Thus, a negative value indicates a worse performance in the dual-task condition than the single-task condition. 
Secondary outcome measures considered for this study are: (1) The frequency, severity and impact on quality of life of UI was determined through the International Consultation of Incontinence Questionnaire-short form (ICIQ-SF) and (2) Cognition status was measured using the Montreal cognitive assessment. 

Statistical analysis
The Statistical Package for the Social Sciences (SPSS 21.0 for Windows) was used for statistical analysis.  To compare TUG performance and DTE during different experimental conditions, repeated measures analysis of variance (ANOVA) was used. For all comparisons, alpha was set at 0.05. For assessing the correlation between ICIQ and DTE the Kendall correlation was used. For this analysis, a correlation of 0.10 to 0.19 = weak, 0.20 to 0.29 = moderate and ≤ 0.30= strong.

Thirty women (72.76 ± 5.87 years) participated in this study. The MoCA scores show that 20 participants met the threshold for normal cognition (25.24 ± 5.20). Although ten participants scored below the 26 points cut off, they were all community-living, independent in their activities of daily living, walk without assistance, thus, meeting the inclusion criteria of the present study. Participants ICIQ scores ranged from no incontinence to severe incontinence. However, most of our participants had either mild incontinence (n=9) or moderate incontinence (n=10).

The repeated measure ANOVA showed that there was a significant effect of the experimental conditions on TUG performance (p <0.001]) in older women. Post hoc comparirisons demonstrated that the time to perform TUG test increased significantly when performing a motor (p <0.001) or cognitive (p < 0.01) secondary task compared to single-task performance. In addition, the full bladder condition significantly increased the time to perform TUG test compared to the equivalent motor (p <0.05) and cognitive (< 0.01) no-desire-to-void condition (Figure 1). 
Similar findings were observed for the DTE results. Repeated measure ANOVA showed a significant effect of the experimental conditions on DTE (p <0.01]). Post hoc comparisons demonstrated that full bladder condition significantly increased DTE compared to the equivalent motor (p <0.01) and cognitive (p < 0.01) empty bladder condition. Finally, DTE was significantly increased during cognitive dual tasking with full bladder compared to every other experimental condition (Figure 1).
There was a moderate and significant positive correlation between the ICIQ and TUG cognitive time performance during full bladder condition (|τb| = 0.292, p=0.030) (Table 1).

Our results confirm that experiencing a full bladder sensation while walking negatively impacts gait performance in aging women. Maintaining a consistent and stable gait and avoiding falling requires cognitive resources and conscious thought processes. With additional tasks, functional gait performance declines indicating a cognitive cost from dual-tasking (motor or cognitive) and an added cognitive cost from the full bladder sensation. This means that dealing with a full bladder sensation may be a source of diverted attention. Older adults have reduced cognitive resources compared to younger adults and a higher risk of falling. 
Persons aged between 70-79 who perform the TUG test slower than 9.2 seconds are at a greater risk of falling. Interestingly, during the cognitive dual tasking with a full bladder our participants, who are on average 72.76 ± 5.87 years old, took on average 13.32 (5.06) seconds to complete the TUG test during the cognitive dual-task with a full bladder. This score exceeds the normative values for their age range, indicating that they have an increased risk of falling when walking, performing a cognitive dual task with a full bladder.

Experiencing a full bladder sensation negatively impacts cognitive functioning, acting as a source of diverted attention during dual-tasking in older women. In addition, aged women experiencing severe UI had their TUG significantly impacted demonstrating an increasing risk of fall during gait.

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Continence 7S1 (2023) 100990
DOI: 10.1016/j.cont.2023.100990