Dystonic head tremor in paroxysmal dyskinesia in 17 dogs (2021–2023)

Abstract

Background: Dystonia is a common component of the movement disorder paroxysmal dyskinesia (PD) in dogs. However, the incidence of dystonic head tremor (DHT) in these dogs has not previously been evaluated. Methods: The medical records of dogs presenting with PD between 2021 and 2023 were retrospectively reviewed, and those with available video footage and the presence of a head tremor were selected for further analysis. Results: Seventeen of the 39 (43.6%) dogs diagnosed with PD that had video footage available manifested DHT. Poodle or Poodle-cross was the most commonly affected breed (7/17). DHTs were described as fine irregular head tremors accompanied by cervical dystonia (17/17), truncal (11/17) or head (10/17) sway, shifting limb (10/17) or single limb (6/17) dystonia, freezing (8/17), ataxia (6/17), ptyalism (5/17), falling (5/17), kyphosis (4/17) and prayer posture (4/17). Neurological examination and advanced imaging, when available, were within normal limits. Limitations: The limitations of the study include its retrospective nature, the lack of video recordings for all PD patients and the lack of electrophysiological evaluation of tremors and electroencephalography. Conclusions: DHT exists in dogs with PD; it has characteristic features, and it should be considered in differential diagnoses for dogs with head tremors.