Impact of simultaneous subthalamic and nigral stimulation on dysphagia in Parkinson’s disease

Abstract

Objectives: Dysphagia is a frequent and highly relevant symptom in Parkinson's disease (PD) due to high associated morbidity and mortality. To compare the effect of simultaneous stimulation of the subthalamic nucleus (STN) and substantia nigra (SNr) with conventional STN-stimulation on swallowing function in Parkinson's disease. Methods: In this controlled, randomized, doubleblind, cross-over clinical trial, 15 PD patients were assessed with DBS switched off (STIM OFF), STN-DBS, STN + SNr-DBS. Patients and 32 age-matched healthy controls were examined clinically and by flexible-endoscopic evaluation of swallowing (FEES) to evaluate the swallowing function. The primary endpoint was the assessment of residues, secondary endpoints were penetration/ aspiration, leakage, retained pharyngeal secretions, drooling, and assessments of the patient's self-perception of swallowing on a visual analog scale. Results: Compared with healthy controls PD patients showed significantly more pharyngeal residues in STIM OFF and both DBS modes. Residues or aspiration events were found in 80% of the patients under STN-stimulation. Simultaneous STN + SNr-stimulation had no additional positive effect on objective dysphagia and self-reported swallowing function compared to STN-DBS. Interpretation: Simultaneous STN + SNr-stimulation seems to have no additional beneficial effects on dysphagia when compared with conventional STN-stimulation, but did not deteriorate the swallowing function. If STN + SNr-stimulation is planned to be applied for the improvement of axial symptoms and gait disorders in PD patients, it can be considered safe in terms of dysphagia. 628

Neurogenic Dysphagia

“…Parkinson disease Pharyngeal residue, 15,36-41,e19,e26-e30 sometimes reported in nearly all patients, 37,39 often reported as leading finding, [36][37][38][39][40][41] with predominance in the valleculae 37,38,e19,e30 Premature bolus spillage 15,38,e27-e30 Impaired swallowing reflex 47,e29,e30 Pharyngolaryngeal movement disorders 15,47,e29,e31 Rarely reported: impaired secretion management e27,e28…”

“…However, residue in the valleculae was the major dysphagia manifestation in PD, which is in line with the results of previous studies. [35][36][37][38][39][40][41] Possibly, oropharyngeal bradykinesia contributes to reduced bolus clearance with accumulation in the valleculae in PD. 15 The phenotype of residue with predominance in the sinus piriformis was seen only rarely in the present study and occurred mainly in medulla oblongata stroke and inclusion body myositis.…”

Consensus on the treatment of dysphagia in Parkinson's disease

“…Results from studies on the effects of DBS on swallowing function are controversial. Twelve studies (3 Class II [48][49][50], 9 Class IV [51][52][53][54][55][56][57][58][59]) were retrieved from literature search. In the majority of the studies, DBS targeted the bilateral STN and was delivered with high frequency stimulation.…”

“…Two studies compared the stimulation of the STN with the stimulation of the GPi [48,55], while one study targeted the caudal zona incerta [57]. Another study compared bilateral stimulation in STN with the combined stimulation of STN and substantia nigra [50]. In one study, the stimulation was unilateral [55].…”

Effect of Deep Brain Stimulation on Swallowing Function: A Systematic Review

“…Kraus reported that at least three patients developed worsening dysphagia or new dysphagia after bilateral STN DBS in a group of 27 PD patients during a mean of 30 months follow-up, based on the assessment for adverse effect, with unclear medication state though (8). Add-on stimulation of substantia nigra reticular (SNr) to STN did not have beneficial effect (41). Worsening of the dysphagia could be related to the suboptimal placement of the DBS electrodes or suboptimal programming in some cases, as turning off or reprogramming of the DBS made the swallowing symptoms better or go away in these cases (42,43).…”