Dystonia in Four-Legged Friends

Dystonia in Four-Legged Friends

Several hyperkinetic movement disorders described in dogs and livestock show similarities to human movement disorders, especially paroxysmal dystonia and dyskinesias. A team of investigators partially supported by the DMRF recently published a report exploring the possibilities that distinct neurological movement disorders in domestic animals represent dystonia. The hope is that animals may help investigators advance our understanding of human dystonia.

The study describes a number of case reports, including a Great Dane dog with severe blepharospasm aggravated by stress and bright light. The spasms progressed to permanent closure of the eyelids. EMG revealed overactivity of the orbicularis oculi muscle, the same muscle involved in human blepharospasm. Botulinum neurotoxin injections finally relieved the symptoms.

Episodic falling in Cavalier King Charles Spaniels is an inher- ited disorder that shares similarities with human paroxysmal dyskinesias. In affected dogs, exercise and excitement trigger episodes of abnormal gait and falling that can last several minutes. There may be sustained extension of the limbs and back arching. The dogs do not lose consciousness. A genetic mutation has been identified, but how the mutation leads to symptoms is unknown.

It has yet to be verified whether these and other movement disorders in domestic animals represent dystonia, but future study may help clarify.