A large retrospective cohort study conducted at the Mayo Clinic in Jacksonville, Florida, compared clinical characteristics among the 4 Parkinson disease subtypes: tremor dominant (TD), gait difficulty, akinetic-rigid (AR), and mixed.
The investigators identified a total of 1003 patients with PD, 694 of whom visited their clinic more than once, with a median length of time of 3.7 years between the initial and the final visits. Data were compiled on motor/nonmotor symptoms at the initial and final visits. The median patient age at PD onset was 64 years.
TD was the most common PD subtype (44%), followed by AR (29%), mixed (18%), and gait difficulty (9%). Median disease duration was 3 years at the initial visit and 7 years at the final visit. Rapid progression of PD was associated with the emergence of falls, dementia, or dependency within 5 years of disease onset.
Rapid disease progression was reported significantly more often among participants with the gait difficulty subtype vs those with the AR subtype (odds ratio [OR] 3.59; P <.001). Moreover, hallucinations at the final visit were significantly more likely to occur in the AR subtype (OR 2.36; P =.005) and the mixed subtype (OR 3.28; P < .001) compared with the TD subtype.
The researchers concluded that the study findings suggest that gait disturbance is an independent prognostic factor and that it may be best to treat the PD subtype characterized by gait difficulty differently from the AR subtype. Additional studies that focus on the clinicopathologic and genetic differences between the gait difficulty and AR subtypes of PD are warranted.
Konno T, Deutschländer A, Heckman MG, et al. Comparison of clinical features among Parkinson’s disease subtypes: a large retrospective study in a single center. J Neurol Sci. 2018;386:39-45.