Objective: We aim to correlate brain-gut neuropathy amongst cortico- and lumbosacro-anorecal efferent pathways in PD subjects with severe constipation measured by prospective stool diary.

Background: Constipation is a common and early non-motor symptom in Parkinson’s disease (PD). Our group has discovered efferent brain-gut neuropathy on novel bidirectional brain-gut testing in PD subjects with constipation compared to healthy subjects. It is unclear whether these findings correlate to degree of constipation.

Method: Bilateral single-pulse transcranial magnetic stimulations (TMS) and trans-lumbosacral anorectal magnetic stimulations (TAMS) were performed to assess the efferent pathway and obtain anal and rectal motor evoked potentials (MEPs). Neuropathy was defined by latencies prolonged >2 SD above healthy subject mean MEP latencies. Daily bowel movements were assessed by a prospective stool diary. Severe constipation was defined by no complete spontaneous bowel movements (CSBMs)/week. Severity of PD was assessed by the Hahn-Yahr (HY) stage.

Results: 25 patients with PD (66.6 ± 8.4years, F/M=6/19) were enrolled. 72 percent of PD patients (18/25) had <3 CSBMs per week, of whom six (24%) had severe constipation. There was significant but weak odds of severe constipation with neuropathy in most cortico-rectal and anal pathways except the left cortico-rectal pathway, shown in Table 1. The correlation significantly improved with increased number of pathways affected by neuropathy (r=0.594; p=0.004). There was no significant correlation between individual or cumulative peripheral lumbosacral-rectal and anal neuropathy and degree of constipation. Furthermore, there was no correlation between cortical or lumbosacral anorectal neuropathy and the HY stage.

Conclusion: Our study demonstrates that central cortico-anorectal neuropathy, but not peripheral neuropathy, in PD significantly correlates with constipation severity directly assessed by a prospective stool diary. This objective neurophysiological assessment of brain-gut dysfunction in PD merits further validation. Acknowledgement: Parkinson’s Foundation Clinical Research Award.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/the-presence-of-efferent-brain-gut-neuropathy-correlates-with-severe-constipation-in-parkinsons-disease/