Predictive markers for early conversion of iRBD to neurodegenerative synucleinopathy diseases

Nice new paper on predictors for conversion to a 'degenerative synucleinopathy' in patients with iRBD... as expected DAT SPECT is one of those predictors... this field is shaping up nicely in terms of identifying a group to trial neuroprotective agents directed against abnormal and aggregated synuclein... a word of caution, as always, degenerative synucleinopathy describes PD, MSA and LBD, not simply PD... 

Yuanyuan Li, PhD, Wenyan Kang, PhD, Qiong Yang, MS, Lina Zhang, MS, Linyuan Zhang, PhD, Fangyi Dong, MS, Shengdi Chen, MD, PhD and Jun Liu, MD, PhD

Neurology
Published online before print March 22, 2017, doi: http:/​/​dx.​doi.​org/​10.​1212/​WNL.​0000000000003838 Neurology 10.1212/WNL.0000000000003838

http://www.neurology.org/content/early/2017/03/22/WNL.0000000000003838.short?rss=1&utm_source=dlvr.it&utm_medium=twitter

Objective: To determine the predictive value of clinical assessment and dopamine transporter (DAT) uptake for the early development of neurodegenerative synucleinopathy diseases from idiopathic REM sleep behavior disorder (iRBD) over 5 years in a Chinese population.

Methods: Forty-three patients with iRBD were administered clinical assessment tests, and 35 were examined by DAT-SPECT imaging during 2011. Cox proportional hazard and Kaplan-Meier analyses were used to evaluate the predictive value of the markers in a follow-up study over 5 years.

Results: Eighteen patients (41.9%) developed neurodegenerative synucleinopathy diseases after a median of 4.1 years of prospective follow-up (median interval of 10.5 years from the estimated onset of iRBD symptoms). Patients with higher scores on the Nonmotor Symptom Questionnaire (hazard ratio [HR] 3.11, 95% confidence interval [CI] 1.15–8.40, p = 0.026) and Scale for Outcomes in Parkinson Disease–Autonomic questionnaire (HR 4.46, 95% CI 1.64–12.10, p = 0.003) were more likely to develop neurodegenerative synucleinopathy diseases. Furthermore, the population with decreased 99mTc-TRODAT-1 binding in the left striatum (HR 2.7, 95% CI 1.02–7.14, p = 0.046) and putamen (HR 3.23, 95% CI 1.16–8.33, p = 0.024) had a relatively higher risk of developing neurodegenerative synucleinopathy diseases.

Conclusions: Our findings elucidate the predictive value of autonomic dysfunction and DAT uptake in identifying patients with iRBD at a high risk of progressing into neurodegenerative synucleinopathy diseases and could form a basis for future disease-prevention trials.