Thalamic movement disorders

•  Patients were divided into four groups: 

  • absence of abnormal involuntary movements (AIM) (nine patients)
  • isolated dystonic posture (two patients
  • myoclonic dystonia (five patients)
  • tremor or myoclonus (six patients)
• 
  
  1. In patients with AIM, thalamic lesions were contralateral to the abnormal movements
  2. involving the thalamogeniculate territory
  3. centered on the ventral intermediate (Vim) and ventral caudal (Vc) nuclei
  4. 
     
  5.  No significant difference in the volumes or center of mass of the lesions
     was found between patients with tremor and myoclonus and patients with dystonia, although the central nucleus and the
     internal part of the Vim nucleus were more consistently damaged in dystonic patients. 
  
  Conclusion: Movement disorders related to thalamic lesions included: 
  1. myoclonic dystonia with predominating myoclonus and “thalamic” hand associating dystonic posture and slow, pseudo-athetoid movements, both related to lesions in the Vim and Vc nuclei of the
     thalamus; and 
  2. postural and action tremor, also related to lesions in the Vim, similar to tremor associated with midbrain
     lesions, as a result of abnormal functioning of the cerebellothalamic pathways.