Previous studies have recognized vertical laryngeal tremor as a prevalent laryngeal abnormality in patients with Parkinson's disease, with manifestations even in the early stages of the disease (1).  

A woman in her 70s with Parkinson’s disease (PD) presented with unusual movements of her larynx while in the medication OFF state, most consistent with tremor (Video 1). Laryngeal tremor was only seen during OFF time. When OFF, she also had chin and perioral tremor, both of which were regular and had a classic appearance of tremor but were not always in sync with the laryngeal movements. EMG showed rhythmic, at times sustained, activity of the mylohyoid (Video 2). When DBS to the globus pallidus interna (GPi) was turned ON or when in the ON medication state, the laryngeal movements resolved (Video 3).  

She had no history of peripheral nerve injury and no prior use of neuroleptic drugs to suggest tardive syndrome. Brain MRI (Figure 1) did not reveal any lesions of the Mollaret triangle nor of the trigeminal nerve. 

The exclusive occurrence of laryngeal tremor during OFF periods suggests its association with dopamine deficiency, and the positive response to GPi DBS further supports this connection. The efficacy of GPi DBS in controlling tremors may be attributed to its modulation of the striato-pallidal circuit, which triggers tremor-related activity in the cerebello-thalamo-cortical circuit through the motor cortex (2).   

Moreover, connectome analysis reveals increased connectivity with the precentral gyrus, particularly the corticobulbar tract following GPI DBS in contrast to Vim DBS (3), potentially explaining its benefit in patients experiencing laryngeal tremor. This case contributes to the growing knowledge of laryngeal manifestations in Parkinson's disease and their response to DBS.