Abstract: Objective  To compare the changes in anorectal function between patients with Parkinson's disease  constipation (PDC) and with functional constipation (FC), and further understand the constipation characteristics of PDC patients.  Methods  From 2017 to 2022, 34 patients with PDC and 39 patients with FC who visited the Department of Neurology and the Department of Gastroenterology in Xuanwu Hospital, Capital Medical University were selected as the observation group and the control group. High resolution anorectal manometry was used to detect the motility, sensation and reflex of anorectal sphincter and pelvic floor muscles in the two groups of patients with constipation, and to compare the anorectal function changes of the two groups of patients. according to the results of manometry, the characteristics of constipation in the two groups of patients were analyzed and compared. Results  The resting anal sphincter pressure and intrarectal pressure in the PDC group were significantly lower than those in the FC group, with statistical significance［ (71.73 ± 20.01)mmHg  vs (85.02 ± 19.74)mmHg, (22.30 ± 21.12)mmHg vs  (38.10 ± 17.00)mmHg, respectively, 1 mmHg=0.133 kPa,all P<0.05］.The length of high pressure zone,maximum squeeze pressure, continuous systolic time and anal relaxation rate in PDC group were lower than those in FC group, but   no statistically significant differences; The maximum tolerance threshold of patients in the FC group was significantly higher than that in the PDC group, but there was no statistically significant difference between the two groups. There was no statistically significant difference in rectanal inhibitory reflex, initial sensory threshold, initial defecation threshold, and rectal compliance between the two groups. According to the pressure measurement results, it was found that both groups of patients mainly had insufficient defecation thrust.The proportions of insufficient defecation propulsion in PDC group and FC group were 88.2% (30/34) and 59.0% (23/39), the proportions of dyscoordination were 11.8%（4/34） and 30.8%（12/39）, and the proportions of normal defecation propulsion without uncoordinated defecation were 0% and 10.3%（4/39）, respectively. There was significant difference between the two groups in the type composition ratio of defecation disorder (χ²=8.623，P<0.05).Conclusions  Both PDC patients and FC patients have abnormal rectal and anal motility and sensation, and the main manifestation of pressure measurement classification is insufficient defecation thrust. However, compared to FC patients, PDC patients have significantly lower anal resting pressure and rectal defecation pressure. In depth research on the changes in anorectal function and constipation characteristics of PDC patients can help improve understanding of the disease and provide relevant evidence for developing reasonable treatment plans for PDC.

Key words: Parkinson's disease constipation, functional constipation, anorectal manometry