To assess the incidence and prevalence of motor fluctuations and deep brain stimulation (DBS) implantation in two parkinsonism cohorts from south-east Minnesota.

No previous studies have calculated incidence of motor fluctuations and DBS implants in a population-based cohort of parkinsonism.

We used the Rochester Epidemiology Project (REP) to investigate a population-based cohort of parkinsonism between 1991-2005 in Olmsted County, MN, and extended our search to the 6 surrounding counties using the expanded REP (eREP) to detect all incident cases of early-onset parkinsonism (defined as diagnosed before 55 years of age) between 2010-2015. A movement disorder specialist reviewed all medical records to confirm the diagnosis of Parkinson’s Disease (PD).

In the 1991-2005 cohort, there were 312 PD. Among these, we found 51 (16%) patients with motor fluctuations (incidence 2.60 cases per 100,000 person-years); DBS was implanted into 15 (29%) of these (incidence 0.76 cases per 100,000 person-years). In the 2010-2015 cohort (<55 years), there were 28 early-onset PD (EOPD). Of these, 14 (50%) had motor fluctuations (incidence 1.02 cases per 100,000 person-years) and 5 (36%, incidence 0.37 cases per 100,000 person-years) underwent DBS implantation. Among the remaining 9 non-DBS EOPD patients with motor fluctuations, DBS was discussed or planned in 7 (78%) of them but was yet to be performed.

Although motor fluctuations had a lower prevalence in the 1991-2005 cohort (not age restricted), compared to the 2010-2015 cohort (age restricted to those <55 years), there was a higher incidence. DBS was implanted in 29% of PD with motor fluctuations in the 1991-2005 cohort and in 36% of EOPD with motor fluctuations in the 2010-2015 cohort, with an incidence of, respectively, 0.76 and 0.37 cases per 100,000 person-years. The vast majority of EOPD with motor fluctuations had DBS either performed or planned to be performed in the near future.