to assess whether wearable sensor data using the Parkinson’s Kinetigraph (PKG) or dopamine transporter scan could be used a potential biosignature for constipation in Parkinson’s disease (PD).

Currently there are no specific biomarkers for constipation, a major non-motor symptom (NMS) of PD.

A cross-sectional analysis of 107 participants enrolled in the global Non-motor Longitudinal International Study (NILS; UKCRN No: 10084, database held at King’s College Hospital (London UK)) who also underwent a six day PKG recording at home and a dopamine transporter scan (DaTscan). Constipation scores on question 21 of the validated Non-Motor Symptom Scale (NMSS) were used to stratify participants based on constipation severity: mild 0-3 points (n=70), moderate 4-7 points (n=22), and severe 8-12 points (n=15). Differences in non-motor and motor scores, PKG scores and DaTscan results were assessed by ANOVA testing with correction for multiple testing.

PKG bradykinesia (BK) scores significantly correlated with constipation severity (Spearman’s r=0.219; p=0.022) and were significantly higher in those with severe constipation compared to mild constipation (p=0.008). Scales for Outcomes in Parkinson's disease (SCOPA-M) disability scores were higher in the former group (p<0.001). DAT scan putamen and caudate binding ratios did not correlate with constipation severity (p>0.35).  Total NMSS scores were 36% higher in participants with severe constipation (77.7±35.6) compared to those with mild constipation (49.4±35.6) (p=0.006).

BK scores in PKG appear to be a strong marker for constipation and this association seems to be independent of central dopaminergic neurotransmission as indicated by the lack of correlation with DaTscan.