Intrinsic auricular muscle zone stimulation for Parkinson disease: The EARSTIM-PD Phase II multi-center pilot study results.

BACKGROUND: Studies have suggested that intrinsic auricular muscle zones (IAMZ) stimulation alleviates motor features of Parkinson disease (PD). METHODS: A randomized, blinded, active sham-controlled pilot trial was conducted to evaluate the safety and dose-response-time curve of Earstim using a 3-treatment, 3-period crossover design in PD patients experiencing OFF time on levodopa. Treatments were: short (20-min) IAMZ stimulation; long (60-min) IAMZ stimulation; and 20-min active sham stimulation of non-muscular areas. Assessment time points were: prior to treatment, and 20, 40, 60, 90, and 120 min after treatment onset. Primary safety endpoints were adverse events frequency and severity. Primary efficacy endpoint was the change in MDS-UPDRS motor score at 20 min after treatment onset in the IAMZ treatment groups versus sham. RESULTS: Forty-six individuals consented; 38 were randomized (average age 64 years, 65 % male, mean 8.2 years from diagnosis). No serious adverse events or significant device-related events occurred. At 20 min after treatment onset, motor improvements did not differ between IAMZ treatments versus sham. However, at 60 min after treatment onset, motor improvement peaked on IAMZ treatments compared to sham (difference: 3.1 [-5.9 to 0.3], p = 0.03). While the difference in 120-min AUC change between IAMZ treatments versus sham was not significant, the short-stimulation IAMZ treatment showed the largest aggregate motor score improvement (AUC = -456 points, 95 % CI -691 to -221) compared to sham. CONCLUSION: Earstim was well-tolerated. The greatest motor improvement occurred at 60 min after stimulation onset in the short-stimulation IAMZ treatment, and supports its further study to alleviate OFF periods.

Genome-wide association study of glucocerebrosidase activity modifiers.

One of the most common genetic risk factors for Parkinson's disease (PD) are variants in GBA1, which encodes the lysosomal enzyme glucocerebrosidase (GCase). GCase deficiency has been associated with an increased PD risk, but not all individuals with low GCase activity are carriers of GBA1 mutations, suggesting other factors may be acting as modifiers. We aimed to discover common variants associated with GCase activity, as well as replicate previously reported associations, by performing a genome-wide association study using two independent cohorts: a Columbia University cohort consisting of 697 PD cases and 347 controls and the Parkinson's Progression Markers Initiative (PPMI) cohort consisting of 357 PD cases and 163 controls. As expected, GBA1 variants have the strongest association with decreased activity, led by p.N370S (beta = -4.36, se = 0.32, p = 5.05e-43). We also identify a novel association in the GAA locus (encoding for acid alpha-glucosidase, beta = -0.96, se = 0.17, p = 5.23e-09) that may be the result of an interaction between GCase and acid alpha-glucosidase based on various interaction analyses. Lastly, we show that several PD-risk loci are potentially associated with GCase activity. Further research will be needed to replicate and validate our findings and to uncover the functional connection between acid alpha-glucosidase and GCase.