Aphasia and thalamotomy: important issues.
Patients may present with classical symptoms suggesting aphasia following thalamotomy (repetition, comprehension, fluency and naming abnormalities). They may also present with 'freezing of speech', and this symptom should not be considered as a speech disorder or a symptom of Parkinson's disease progression, without careful testing to rule out language deficits, particularly dysfluency. There are important issues related to all language complications of thalamotomy, including (1) the time course of problems following surgery, (2) the impact of preexistingspeech problems, (3) the importance of the size and location of lesions, (4) the potential circuits important in the pathogenesis of a thalamic language disturbance and (5) whether laterality makes a difference (left- versus right-sided thalamic lesions). As more centers switch from thalamotomy to deep brain stimulation, the issues regarding aphasia will need to be addressed.