Assessment of rectal afferent neuronal function and brain activity in patients with constipation and rectal hyposensitivity

Abstract

This study is the first showing objective evidence of alteration in the rectal afferent pathway of individuals with RH and constipation. Prolonged latencies suggest a primary defect in sensory neuronal function, while cerebral processing of visceral sensory information appears normal.

Abnormal neuronal response to rectal and anal stimuli in patients with idiopathic fecal incontinence

“…We found prolonged latencies of the CEPs elicited from rectal distension suggesting that IFI patients have abnormal afferent pathways from the rectum to the brain. This likely represents aberrant (mechano‐) receptor function or abnormal peripheral conduction velocity, although more central abnormalities cannot fully be excluded . We found the prolonged latencies to be more pronounced in passive IFI sub‐group, suggesting that symptomatology could be linked to the extent of this afferent deficit, but our numbers are relatively small and this should be interpreted cautiously.…”

“…Prolonged CEP latencies after rectal stimuli have previously been described in patients with fecal and urinary incontinence, constipated children, and constipated adults with rectal hyposensitivity . Most of these studies have used electrical stimulation bypassing the end organ receptors, which suggests that the observed changes are not the result of aberrant receptor function but relates to a change in propagation properties of the afferent nerves.…”

“…The percentage of data that cannot be explained by this model is expressed as residual variance. A residual variance of less than 10% is considered to be a good fit …”

Functional anal canal length measurement using high‐resolution anorectal manometry to investigate anal sphincter dysfunction in patients with fecal incontinence or constipation

“…A detailed description of the departmental barium proctographic measurements, endoanal ultrasonography, and rectal sensation to balloon distension has been published previously. Normal rectal sensory threshold values were based on previously published data . Rectal hypersensitivity was defined as a maximum tolerable volume of <75 mL, whereas rectal hyposensitivity was diagnosed when ≥2 sensory thresholds were above normal limits .…”

Rectal Hyposensitivity

“…A recent study in 11 healthy volunteers and 13 patients with constipation and RH looked at the location of the proposed afferent pathway defect in more detail 63. Using evoked potential recording and inverse modeling techniques of cortical dipoles, a temporal delay in afferent transmission in patients in comparison to volunteers was found (142 ± 24 vs 116 ± 15 ms; P = 0.004), although there was no difference in the location of cortical processing.…”