Understanding neuromuscular activity during swallows and rehabilitative maneuvers in patients with Parkinson's disease: A preliminary study

Rehabilitative swallowing exercises are commonly used to either strengthen and/or improve coordination/timing of swallowing muscles in patients with Parkinson’s disease (PD) (Robbins et al., 1986); however, the potential effect of these exercises on the neuromuscular control of swallowing has yet to be explored in this patient population. This preliminary project focused on examining neuromuscular amplitude and timing components in typical swallows (5mL thin liquid and 5cc pudding) and maneuvers (effortful swallow and Mendelsohn maneuver) in a group of patients with idiopathic PD. A cross-sectional prospective study was completed. Data were collected on 15 participants (Mean age 70.5 ± 8.03; N=9 females; N=6 males) pre- and post a one-hour intervention session and included simultaneous data collection of surface electromyography (sEMG) and videofluroscopy (VFSS). This study focused on the pre-treatment sEMG data. Surface EMG data were collected from the submental muscles during typical swallows and maneuvers. The following sEMG outcome variables were examined: burst duration (BD) of the smoother sEMG signal, normalized mean sEMG amplitude, and time-to-peak sEMG amplitude. Overall, our results revealed that patients with PD elicited the longest burst duration for the Mendelsohn maneuver, the highest normalized mean amplitude for the effortful swallow, and the fastest TTP during 5mL thin liquid trials. To our knowledge, this is the first study that offers insights into the neuromuscular contributions of swallowing maneuvers in PD patients, and future research should support and expand upon these findings to offer important evidence on how and when to prescribe these rehabilitative maneuvers to patients with PD.