Biomedical subjects

M Broniatowski

Publications and source records attributed to M Broniatowski.

59 records · Page 4Linked to original sources

PubMedDate not supplied

The potential for neurostimulation in obstructive sleep apnea.

Obstructive sleep apnea affects millions of individuals. It usually is due to pharyngeal collapse during sleep, resulting in daytime somnolence. This can have grave consequences on everyday life and in the long term can lead to pulmonary and systemic hypertension, myocardial disease, and stroke. Non-structural obstructive sleep apnea can be relieved by tracheostomy and continuous positive airway pressure, two methods that bypass the overly compliant pharyngeal musculature during inspiration. It may well be desirable to exchange a dynamic and more physiologic approach to obstructive sleep apnea for these purely static solutions. This approach should restore disturbed cyclical stiffening of the upper airway by electronically stimulating the appropriate muscles, timed by information originating during the inspiratory effort. The open-loop systems proposed here are based upon principles pioneered by us for the rehabilitation of the paralyzed larynx that are now well within practical reach of current technologies.

Electric Stimulation↗

PubMedDate not supplied

Electronic pacing of incapacitated head and neck structures.

Paralysis in the head and neck can affect any motor or mixed cranial nerves and the cervical roots. Most conspicuous deficits, however, involve the larynx and the face. The capacity for denervated striated muscle to undergo reinnervation, and the presence of remaining sources of information, have allowed coordinated rehabilitation of incapacitated cervical neuromuscular systems. The object of further related research should focus on the long-term efficacy of the reinnervated muscle machinery and the potential complexities of electronic integration.

Animals↗

PubMedDate not supplied

Excitation thresholds for nerves reinnervating the paralyzed canine larynx.

Electrical stimulation of paralyzed laryngeal muscles implanted with nerve-muscle pedicles (NMP) has resulted in documented return of motion. No study, however, has yet determined how NMP excitability correlates with that of normal muscle or nerve. In six anesthetized dogs, one hemilarynx was denervated and the paralyzed thyroarytenoid, cricothyroid, and posterior cricoarytenoid muscles were reinnervated via NMPs originating from the ansa hypoglossi nerve. After 4.6 to 5.7 months, an electric stimulator delivering biphasic pulses of variable amplitude and widths was used to test thresholds for contraction in nine stimulatable NMPs, six intact recurrent laryngeal nerves (RLN), and five normal cervical muscles. With one exception (2.1 mA), NMP rheobases varied between 0.0002 and 0.04 mA (mean = 0.020 SD +/- 0.012, n = 6). Two NMPs belonging to animals stimulated for several hours had higher values (0.1 mA). Rheobase varied from 0.01 to 0.09 mA for control RLNs (mean = 0.058 SD +/- 0.025), and from 0.05 to 0.35 mA for muscles (mean = 0.144 SD +/- 0.109). Histologic correspondence with reinnervation was established in implanted muscles by type grouping on ATPase stains. These data suggest that 1) nerve pedicles may offer promise for the eventual construction of implantable low energy consuming laryngeal devices, and 2) the appropriate charge to be injected over time remains to be determined.

Animals↗

PubMedDate not supplied

New horizons in dynamic rehabilitation of paralyzed laryngeal functions.

Bilateral vocal cord paralysis can result in inspiratory difficulty, while stroke can impair swallowing and be followed by severe aspiration. Ideally, these mutually exclusive functions must be rehabilitated dynamically. The principle of the artificial reflex arc (ARA) entails appropriate pick-up information, which is then sent to a modulator that in turn synchronously stimulates the impaired effector. In vocal cord paralysis (six dogs), respiratory information has been picked up via tracheal strain gauges and transthoracic impedance electrodes, producing an analog voltage proportional to respective changes during inspiration. A trigger and a stimulator circuit were used to drive an electrode placed around a nerve-muscle pedicle previously implanted into the posterior cricoarytenoid muscle. Two msec square waves with 1.8 V amplitude and 50 Hz frequency resulted in frank vocal cord abduction synchronous with inspiratory flow. Conversely, vocal fold closure can be paced from information originating from strain gauges placed on the hypopharynx (four dogs). Stretch stimulating deglutition resulted in controlled output of a constant current stimulator driving an electrode passed around both recurrent laryngeal nerves. An adjustable stimulus from 0 to 20 mA at 25 Hz produced tetanic closure of the vocal folds. This might offer promise for electronic control of the transplanted larynx.

Animals↗

PubMedDate not supplied

Electronic control of pathologic tone disturbances in the larynx.

The complex anatomy of the larynx and the wide varieties of disturbances potentially affecting the tension of its constituent muscles give rise to various clinical presentations. Whatever the causes of pathologic tone disturbances affecting the larynx, rehabilitation should start by focusing on the dynamic adjustment of glottic tension in the muscles that have become separated from their respective central nervous system command centers. The objective of laryngeal rehabilitation is combined restoration of individual behaviors such that mutual, global relationships simulating those present before disability are reestablished.

Electric Stimulation↗