Aims:The primary aim of this study was to assess the relationship between a strong desire to void (SDV) and rectal sensory function in patients with multiple sclerosis (PwMS) and anorectal disorders. The secondary aim was to identify clinical, urodynamic or manometric factors associated with greater rectal sensory function impairment in this population.Methods: Thirty PwMS (mean age 49.2 ± 10.9 years) with anorectal disorders (constipation and/or fecal incontinence) participated in this observational study. Rectal sensory parameters during anorectal manometry were recorded at a strong desire to void and after urination (PV, post-void). The primary outcome was the desire to defecate volume. Secondary outcomes were first perception and maximum tolerated threshold volumes, presence and modulation of recto-anal inhibitory reflex. Results: The mean desire to defecate volume was 125 ± 59 mL at SDV and 104 ± 64 mL at PV (P < .001). The mean maximum tolerated volume was 167 ± 61 mL at SDV vs 141 ± 64 mL after urination (P = .01). The other parameters were not different between SVD and PV conditions. No predictive factors for greater impairment of rectal sensory function were identified. Conclusion: This study suggests a relationship between bladder sensation and thus bladder capacity, and rectal sensory function in PwMS and with anorectal disorders. K E Y W O R D S multiple sclerosis, neurogenic, rectal diseases, rectal sensation, sensation, urinary bladder Abbreviations: ARD, anorectal disorders; EDSS, Expanded Disability Status Scale; LUTS, lower urinary tract symptoms; MS, multiple sclerosis; NBD, neurogenic bowel dysfunction; OAB, overactive bladder; PwMS, patients with multiple sclerosis; PV, post void; RAIR, recto-anal inhibitory reflex; SDV, strong desire to void; SUI, stress urinary incontinence; USP, urinary symptom profile score.|