Paced Glottic Closure for Controlling Aspiration Pneumonia in Patients with Neurologic Deficits of Various Causes

Abstract

Purpose of the study To determine whether paced vocal fold adduction can check aspiration in patients with various neurological conditions. Design and method of study and analysis Five patients with fluoroscopically documented aspiration and repeated pneumonias were enrolled. Two previously reported patients with hemispheric stroke* were compared to three additional subjects with brainstem-basal ganglia and cerebellar stroke (BSBGC), cerebral palsy (CP) and multiple sclerosis (MS). A modified Finetech-Brindey stimulator was implanted subcutaneously and linked to the ipsilateral recurrent laryngeal nerve via perineural electrodes. Vocal fold adduction and glottic closure were effected with pulse trains (42 Hz, 1.2 mA, 188–560 μsec) and recorded with Enhanced Image J ®. Fluoroscopy results with and without stimulation were assessed by two independent blinded reviewers. Pneumonia rates were compared before, after and during the 6–12 months enrollment periods. Summary of results There was statistically significant vocal fold adduction (p < .05) for all patients, further verified with bolus arrest (p < .05 for thin, thick liquids and puree depending on the speech-language pathologist). Pneumonia was prevented in four of the five patients during enrollment. The fifth patient with BSBGC was unable to completely seal the glottis and open the cricopharyngeus enough to handle his secretions. Conclusions Vocal fold pacing for aspiration pneumonia from a variety of neurological insults appears appropriate as long as the glottis can be sealed. It is not sufficient when the cricopharyngeus must be independently opened.

Selective intraoperative stimulation of the human larynx

“…7) within given stimulation series. We therefore submit that traditional waveforms should be limited to situations where intermuscular balance may be at least temporarily disregarded, such as short term, intermittent (i.e., non‐fatigue prone) activation of functions carried by muscles endowed with homogeneous anatomical and histochemical organization (e.g., evoked glottic closure for swallowing) 7, 8…”

“…QT pulses could potentially target erratic ILM behavior associated with those conditions to elicit a more orderly muscle response. An upgrade of our current implantable laryngeal stimulator7, 8 could use information from erratic PCA/TA coupling, with or without faulty LCA involvement. With further experience, we may also be able to define electrical stimulating parameters corresponding to vectorial anatomy.…”

“…The stimulating currents were modulated by pulse amplitude (PA), pulse width (PW), and exponential decay (Exp), and certain stimulating windows resulted in complete release of maximal vocal fold adduction varying from subject to subject. Although the TA was obviously targeted,13–15 neither this nor our later study of human vocal fold adduction by an implanted stimulator7, 8 specifically sought, addressed, demonstrated, or calculated the specific participation of individual ILMs in the process 13, 14…”

“…Functional electrical stimulation (FES) has successfully restored various neurological deficits in systems such as the limbs, bladder, and diaphragm using square wave stimuli. We have previously reported laryngeal application of FES for aspiration after stroke using an implanted pacemaker to effect dynamic glottic closure by stimulating the laryngeal adductors with traditional envelopes 7, 8. In those studies, however, we ignored the participation of the PCA.…”

Recurrent laryngeal nerve transection in mice results in translational upper airway dysfunction

“…Unfortunately, treatments that restore normal physiologic function after RLN injury are lacking (Chandrasekhar et al, ; Choi et al, ; Wang, Yuan, Xu, et al, ). Current strategies include voice therapy (Anderson & Arnold, ; Araki et al, ; Broniatowski et al, ; Neel et al, ) and medialization of the impaired VF (Anderson & Arnold, ). Alternative secondary surgeries, such as RLN anastomosis, may increase background muscle activity, but do not guarantee return of normal VF mobility (Choi et al, ).…”