Dystonia associated with pontomesencephalic lesions

Area of Science:

• Neurology
• Neuroscience
• Movement Disorders

Background:

• Secondary dystonia is typically associated with basal ganglia or thalamic lesions.
• The pathoanatomical correlations of brainstem lesions causing dystonia are not well understood.

Observation:

• This study reports on four patients with acquired dystonia following brainstem lesions, specifically pontomesencephalic hemorrhage or diffuse axonal injury.
• No concurrent basal ganglia or thalamic lesions were observed in these patients.
• Dystonia onset was delayed, ranging from 1 to 14 months post-lesion.

Findings:

• Patients presented with hemidystonia, cervical dystonia, and in some cases, craniofacial dystonia and tremors.
• Dystonia was persistent in most patients, with limited response to medical treatments.
• Thalamotomy provided improvement for one patient with severe symptoms.

Implications:

• Pontomesencephalic lesions, including the tegmentum and superior cerebellar peduncles, can lead to dystonia with phenomenology similar to basal ganglia/thalamic lesions.
• Delayed-onset brainstem dystonia, though rare, should be considered in patients with relevant lesions.
• Mild dystonia manifestations may be overlooked in the context of severe brainstem injury deficits.