Although essential tremor (ET) is among the most prevalent neurological diseases, its precise pathogenesis is not understood. Purkinje cell loss has been observed in some studies and is the focus of interest and debate. Expressing these data as Purkinje cells/layer length allows one to adjust for the inherent curved nature of the cerebellar folia. Capitalizing on the Essential Tremor Centralized Brain Repository, we quantified Purkinje cell linear density in cases vs. controls.

Free-floating, 100 μm, parasagittal cerebellar hemispheric sections were subjected to rabbit polyclonal anti-Calbindin D28k antibody, and 10 random fields/brain were selected for quantification of Purkinje cells/mm⁻¹ Purkinje cell layer.

Purkinje cell linear density was lower in 32 ET cases than 16 controls (1.14 ± 0.32 vs. 1.35 ± 0.31 per mm⁻¹, p = 0.03). Purkinje cell linear density was inversely associated with torpedo count (r = −0.38, p = 0.028).

The current sample of ET cases demonstrates a reduction in Purkinje cell number relative to that of controls. Greater Purkinje cell axonal remodeling (torpedoes) was found in individuals who had the most Purkinje cell drop out. The role of Purkinje cell loss in the pathogenesis of this disorder merits additional study.