Table 1: Mechanisms of anorectal dysfunction.

Assessment toolSymptomSample sizeMS severityResultsReference

Anorectal manometryCon21EDDS: 5.3Decreased rectoanal inhibitory reflex[23]
Con or FI39EDSS: 5No difference based on symptom patterns[22]
DSS 5 : 5
Con13DSS 5 : 8 Weak external sphincter: 62 % ; impaired straining: 82 % [11]
Con30EDSS: 6Lower squeeze pressure, impaired valsalva pressures[12]
Con and FI11Lower sphincter pressures in women[35]
Con and FI23Wheelchair: 9Abnormal squeeze pressure in a subset[36]
Con and FI16Impaired amplitude and duration of squeeze pressure[19]
Con and FI52EDSS: 4.13Decreased squeeze pressures[16]
FI6Markedly reduced squeeze pressure[32]
FI12Lower squeeze pressure in women only after childbirth[27]
Con9EDSS: 9.6Decreased squeeze pressure[13]

Recto-anal sensitivityCon and FI39EDSS: 5No differences in rectal or anal sensory thresholds[22]
Con and FI11Normal rectal sensory thresholds[35]
FI5Abnormal sensory threshold to distension in 3/5 patients[19]
Con9EDSS: 9.6Normal rectal and anal sensory thresholds[13]
FI6Normal rectal sensory thresholds[32]
Con and FI52EDSS: 4.13Normal rectal sensory thresholds[16]
Con and FI30EDSS: 6Abnormal sensory threshold to distension in 15 patients[12]

Con: constipation; FI: fecal incontinence; EDSS: expanded disability status scale.