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Biomedical subjects

M Mahowald

Publications and source records attributed to M Mahowald.

4 recordsLinked to original sources

Uvulopalatopharyngoplasty for obstructive sleep apnea: a community's experience.

Uvulopalatopharyngoplasty (UPPP) has become an accepted method for treating obstructive sleep apnea (OSA), with a reported success rate as high as 77%, depending upon inclusionary and outcome criteria. The authors reviewed the records of 90 patients with moderately severe OSA (apnea plus hypopnea index [AHI] greater than 20) who underwent UPPP at either a private community or an academic hospital. Forty percent of patients experienced more than a 50% reduction in their AHI with UPPP. Only 22 (24%) of the patients had a postoperative AHI less than 50% of the preoperative AHI and less than 20, i.e., met the authors' criteria for surgical success. The success rate for community otolaryngologists was no different than that achieved in the academic institution. When data from previously published reports were analyzed using these criteria for success, similar results were observed. This study suggests that the effectiveness of UPPP performed by the general otolaryngologic community is equivalent to that reported in the literature. However, more rigorous criteria must be applied to UPPP when evaluating its results and in counseling potential candidates for this procedure.

Adult

Central sleep apnoea in congenital muscular dystrophy.

Sleep-disordered breathing may occur in a wide variety of neuromuscular syndromes, and may present with diverse, often isolated, symptoms or findings such as excessive daytime sleepiness, pulmonary hypertension, congestive heart failure, morning headaches, or hypoxia-induced nocturnal seizures. The authors report two sisters with congenital muscular dystrophy in whom central sleep apnoea resulted in the isolated symptom of nocturnal seizures in one, and morning headaches in the other. Review of the literature reveals that sleep-disordered breathing may be common in neuromuscular disorders, and may often be present when clinical weakness is mild, and insufficient to result in diurnal respiratory dysfunction.

Adult

Single night studies in obstructive sleep apnea.

The role of single night studies and the determinants of effective nasal continuous positive airway (CPAP) pressures were determined in 412 consecutive patients between 1984 and 1989. Patients chosen for analysis had an apnea index (AI) of greater than or equal to 20 hr-1 prior to CPAP. The AI was 67 +/- 30 hr-1, the body mass index (BMI) was 36 +/- 9 kg/m2, the age was 51 +/- 13 yr and the lowest oxygen saturation was 72 +/- 14%. Effective CPAP (9 +/- 3 cm H2O) was documented in 320 patients on single night studies and resulted in a 99% reduction in the frequency of obstructive events and improvement in the lowest O2 saturation to 94 +/- 5%. Only 18% of the variability in effective CPAP could be explained by AI and BMI. Single night studies are sufficient to establish effective CPAP in 78% of patients and offer considerable conservation of resources compared to routine multiple night studies. Effective CPAP pressures are variable and must be determined by incremental CPAP trials.

Arousal

A silicon neuron.

By combining neurophysiological principles with silicon engineering, we have produced an analog integrated circuit with the functional characteristics of real nerve cells. Because the physics underlying the conductivity of silicon devices and biological membranes is similar, the 'silicon neuron' is able to emulate efficiently the ion currents that cause nerve impulses and control the dynamics of their discharge. It operates in real-time and consumes little power, and many 'neurons' can be fabricated on a single silicon chip. The silicon neuron represents a step towards constructing artificial nervous systems that use more realistic principles of neuronal computation than do existing electronic neuronal networks.

Animals