Using an ambulatory stress monitoring device to identify relaxation due to untrained deep breathing.

The objective of this paper is to assess the efficacy of deep breathing as a relaxation activity using a wearable stress monitor. For this purpose, we developed a protocol with different mentally stressful activities interleaved with regular sessions of deep breathing. We used three physiological sensors: a heart rate monitor, a respiration sensor, and an electrodermal activity sensor, to extract parameters that are consistent with the dominance of the sympathetic nervous system. Our results indicate that a large number of subjects were not able to perform the paced deep breathing exercise properly, which caused their stress levels to increase rather than to decrease. The study also showed that our wearable stress monitor can be used to monitor breathing technique and assess its effectiveness in relaxing individuals.

Development and evaluation of an ambulatory stress monitor based on wearable sensors.

Chronic stress is endemic to modern society. However, as it is unfeasible for physicians to continuously monitor stress levels, its diagnosis is nontrivial. Wireless body sensor networks offer opportunities to ubiquitously detect and monitor mental stress levels, enabling improved diagnosis, and early treatment. This article describes the development of a wearable sensor platform to monitor a number of physiological correlates of mental stress. We discuss tradeoffs in both system design and sensor selection to balance information content and wearability. Using experimental signals collected from the wearable sensor, we describe a selected number of physiological features that show good correlation with mental stress. In particular, we propose a new spectral feature that estimates the balance of the autonomic nervous system by combining information from the power spectral density of respiration and heart rate variability. We validate the effectiveness of our approach on a binary discrimination problem when subjects are placed under two psychophysiological conditions: mental stress and relaxation. When used in a logistic regression model, our feature set is able to discriminate between these two mental states with a success rate of 81% across subjects.

Clinical usefulness of extratympanic electrocochleography in the diagnosis of Ménière's disease.

OBJECTIVE: Electrocochleography has been introduced to aid the diagnosis of endolymphatic hydrops. The aim of this study was to evaluate the clinical effectiveness of extratympanic electrocochleography in the diagnosis of Ménière's disease. STUDY DESIGN: The medical records of patients diagnosed as having Ménière's disease at the department of otolaryngology were reviewed retrospectively. Thirty-seven healthy ears were included to calculate the upper level of the 95th percentile range of the extratympanic electrocochleography variables. SETTING: Tertiary referral university hospital. PATIENTS: One hundred fifty-eight patients (97 women and 61 men) diagnosed as having Ménière's disease without previous treatments were included. A retrospective analysis of their medical records, electrocochleographic results, audiograms, and follow-up records was performed. The mean age was 48.6 years. MAIN OUTCOME MEASURES: The upper level of the 95th percentile range of the extratympanic electrocochleography variables of normal subjects were calculated. Electrocochleography recording results were compared with the diagnostic scale and stage, presence of fluctuating hearing loss, and duration of symptoms. RESULTS: The 95% upper limit for baseline summating potential and action potential ratio was 0.34. Sensitivity and specificity of electrocochleography in the diagnosis of Ménière's disease were 71% and 96%, respectively. The results statistically correlated with the Ménière's current diagnostic criteria and did not correlate with the stage of disease, presence of fluctuating hearing loss, or duration of symptoms. CONCLUSION: Extratympanic electrocochleography may play an important role, especially in patients with less definite symptoms, but the diagnosis should also be anchored in the patient's clinical history, symptoms, and audiogram.