Subject(s)
Electric Stimulation Therapy/instrumentation , Electric Stimulation Therapy/methods , Models, Neurological , Nervous System Diseases/rehabilitation , Prostheses and Implants , Therapy, Computer-Assisted/instrumentation , Therapy, Computer-Assisted/methods , Computer Simulation , Electrodes, Implanted , Equipment Design , Humans , MicroelectrodesABSTRACT
Some additions/corrections are offered to Geddes, 2004. Stimulation is initiated by the second spatial derivative of the voltage along the nerve (activating function) rather than current density. Chronaxie values change with distance from the electrode. Anodic stimulation can excite via anodic break excitation, or via virtual cathodes around the anode.
Subject(s)
Action Potentials/physiology , Cell Membrane/physiology , Chronaxy/physiology , Electric Stimulation/instrumentation , Electric Stimulation/methods , Energy Transfer/physiology , Membrane Potentials/physiology , Animals , Data Interpretation, Statistical , Differential Threshold/physiology , Electric Impedance , Electrodes , Humans , Reproducibility of Results , Sensitivity and SpecificityABSTRACT
Contraction of the genioglossus (GG) has been shown to improve upper airway patency. In the present study, we evaluated responses in upper airway pressure-flow relationships during sleep to electrical stimulation (ES) of the GG in patients with obstructive sleep apnea. Five patients with chronically implanted hypoglossal nerve (HG) electrodes and nine patients with fine-wire electrodes inserted into the GG were studied. Airflow was measured at multiple levels of nasal pressure, and upper airway collapsibility was defined by the nasal pressure below which airflow ceased ["critical" pressure (Pcrit)]. ES shifted the pressure-flow relationships toward higher flow levels in all patients over the entire range of nasal pressure applied. Pcrit decreased similarly during both HG-ES and GG-ES (deltaPcrit was 3.98 +/- 2.31 and 3.18 +/- 1.70 cmH2O, respectively) without a significant change in upstream resistance. The site of collapse (velo- vs. oropharynx) did not influence the response to GG-ES. Moreover, ES-induced reductions in the apnea-hypopnea index of the HG-ES patients were associated with substantial decreases in Pcrit. Our findings imply that responses in apnea severity to HG-ES can be predicted by characterizing the patient's baseline pressure-flow relationships and response to GG-ES.
Subject(s)
Electric Stimulation Therapy , Hypoglossal Nerve/physiology , Sleep Apnea, Obstructive/physiopathology , Sleep Apnea, Obstructive/therapy , Adult , Electrodes, Implanted , Female , Humans , Male , Middle Aged , Polysomnography , Pressure , Tongue/innervation , Tongue/physiologyABSTRACT
A decade of clinical experience has suggested that precentral stimulation is an option for patients with deafferentation as well as other chronic pain syndromes. Permanent complications are uncommon. More scientific evidence is warranted to understand the precise mechanisms for this treatment modality. A larger organized clinical trial is desired to establish the efficacy of precentral stimulation.
Subject(s)
Brain , Electric Stimulation Therapy/methods , Pain Management , Palliative Care/methods , Chronic Disease , Electrodes, Implanted , Humans , Models, NeurologicalABSTRACT
OBJECTIVES/HYPOTHESIS: Electrical stimulation of the posterior cricoarytenoid muscle, when paced with inspiration, offers a physiological approach to restore ventilation in bilateral laryngeal paralysis without any of the disadvantages associated with conventional treatment. STUDY DESIGN: A prospective study of six patients. METHODS: The patients were successfully implanted with an Itrel II stimulator (Medtronic, Inc). In postoperative sessions, stimulated vocal fold abduction, patient ventilation, and voice were assessed and compared with preoperative values. RESULTS: The optimum stimulus paradigm was a 1- to 2-second train of 1-millisecond pulses delivered at a frequency of 30 to 40 Hz and amplitude of 2 to 7 V. Posterior cricoarytenoid stimulation produced a large dynamic abduction (3.5-7 mm) in three patients and moderate abduction (3 mm) in a fourth patient. The fifth patient showed a large but delayed response of 4 mm to stimulation with some lateralization of the vocal fold. In the sixth patient, stimulated abduction was noted on device implantation but was lost postoperatively. All five patients with stimulated abduction postoperatively met the ventilatory criteria for decannulation, and three patients subsequently had decannulation. Long-term stimulation of the posterior cricoarytenoid muscle had no appreciable effect on voice quality. CONCLUSIONS: Electrical stimulation of the posterior cricoarytenoid muscle shows potential as an improved therapy for bilateral vocal fold paralysis.
