Najib T. Ayas

Assessment of a wrist-worn device in the detection of obstructive sleep apnea

OBJECTIVEnTo assess the accuracy of a wrist-worn device (Watch_PAT100) to diagnose obstructive sleep apnea (OSA).nnnMETHODSnThirty adult subjects with and without suspected OSA simultaneously had a standard in-laboratory polysomnogram (PSG) and wore the Watch_PAT100 during a full-night recording. PSG sleep and respiratory events were scored according to standard criteria. Watch_PAT data were analyzed with an automated computerized algorithm which calculated the frequency of respiratory events per hour of actigraphy measured sleep using a combination of peripheral arterial tonometry (PAT) signal attenuation, desaturation on pulse oximetry, and changes in heart rate. This yielded a PAT apnea hypopnea index (AHI).nnnRESULTSnMean age was 47.0+/-14.8 years, mean body mass index 31.0+/-7.6 kg/m(2), mean PSG AHI 23+/-23.9 events per hour, and mean PAT AHI 23+/-15.9 events per hour. There was a significant correlation between PAT AHI and AHI by PSG (r=0.87, P<0.001). To assess sensitivity and specificity of Watch_PAT, we constructed receiver operator characteristic curves using a variety of AHI threshold values (10, 15, 20, and 30 events per hour). Optimal combinations of sensitivity and specificity for the various thresholds were 82.6/71.4, 93.3/73.3, 90.9/84.2, and 83.3/91.7, respectively.nnnCONCLUSIONSnThe Watch_PAT is a device that can detect OSA with reasonable accuracy. Thus, the Watch_PAT may be a useful method to diagnose OSA.

Bilateral oculosympathetic paresis associated with loss of nocturnal melatonin secretion in patients with spinal cord injury.

Abstract Background: Lesions along the sympathetic pathway to the eye produce oculosympathetic paresis (OSP, Horner’s syndrome). The oculosympathetic pathway descends from the hypothalamus through the cervical spinal cord and ascends to the superior cervical ganglion (SCG), which innervates sympathetic targets in the ipsilateral face and eye. This pathway appears to closely co-localize with a similar retino-pineal neural pathway from the hypothalamus through the cervical spinal cord and SCG to the pineal gland. As such, lesions along this shared pathway, such as occur in neurologically complete injury to the cervical spinal cord (tetraplegia), would be predicted to result in simultaneous OSP and loss of pineal melatonin production. Loss of melatonin production may contribute to the pervasive sleep disruption observed in patients with tetraplegia. Methods: We assessed the presence of OSP by photographic documentation of ptosis and pupillary dilation response to cocaine eye drops in 5 individuals with neurologically complete damage to their upper thoracic or lower cervical spinal cord. We correlated these results with an analysis of the pattern of melatonin production in these same individuals. Results: Bilateral OSP was present in individuals with cervical spinal cord injury; each also lacked significant production of melatonin. No evidence of OSP was observed in the 2 individuals with thoracic spinal cord injury below the level of the oculosympathetic pathway. Both had normal circadian rhythms of melatonin production, with timing and amplitude of the rhythm within normal parameters. Conclusion: The presence of bilateral oculosympathetic paresis can be predictive of the complete loss of the nocturnal production of melatonin.