An 85-year-old female with advanced dementia and no history of bowel dysfunction is at risk for fecal incontinence primarily because dementia will impair:

An 85-year-old female with advanced dementia and no history of bowel dysfunction is at risk for fecal incontinence primarily because dementia will impair:

• A. The sampling reflex.
• B. Her ability to respond to the sensations of rectal fullness.
• C. The ability of the internal sphincter to relax.
• D. Colonic transit time.

Answer: (B)

Dementia primarily increases fecal incontinence by diminishing the ability to recognize when the rectum is full and to act on that sensation. In normal function, rectal distension creates a conscious urge to defecate, and the person plans and initiates toileting in time. In advanced dementia, cognitive and sensory processing deficits blunt awareness of rectal fullness, so leakage can occur before a toilet opportunity is found. The sampling reflex and the internal anal sphincter’s relaxation are parts of defecation, but they rely on intact perception and decision-making to translate that signal into voluntary action, which dementia compromises. Colonic transit time can affect stool timing, but it doesn’t explain why perception of rectal fullness is lost in this scenario.

Dementia primarily increases fecal incontinence by diminishing the ability to recognize when the rectum is full and to act on that sensation. In normal function, rectal distension creates a conscious urge to defecate, and the person plans and initiates toileting in time. In advanced dementia, cognitive and sensory processing deficits blunt awareness of rectal fullness, so leakage can occur before a toilet opportunity is found. The sampling reflex and the internal anal sphincter’s relaxation are parts of defecation, but they rely on intact perception and decision-making to translate that signal into voluntary action, which dementia compromises. Colonic transit time can affect stool timing, but it doesn’t explain why perception of rectal fullness is lost in this scenario.