Dysgeusia (or foul taste), a rarely reported side effect in patients who have undergone deep brain stimulation (DBS) in the thalamus for essential tremor (ET), can be reduced by changing stimulation parameters, or surgical revision of the lead, a recent study found. This retrospective study evaluated the incidence, nature, neurophysiological, and anatomical location of dysgeusia following DBS. Of 52 patients who had undergone DBS for ET, 8 (15%) reported dysgeusia, which was described as a “metallic,” “sour,” “foul,” or “cold” taste in the mouth. The anatomical locations of the contacts causing dysgeusia were measured on postoperative MRI, and compared to those from 7 control patients who did not experience dysgeusia after receiving bilateral DBS implants. Researchers found:

• Leads causing dysgeusia were more posterior than non-dysgeusia-associated leads.
• Intraoperative microelectrode recording indicated that these contacts were in the sensory region of the thalamus.
• Intraoperative testing found that low sensory threshold for paresthesia (burning or prickling sensation) predicted the development of dysgeusia postoperatively.
• These data indicate that taste perception can be altered through DBS, with posterior leads likely within the sensory region of the thalamus.