Sleep apnea is a prevalent sleep-related breathing disorder characterized by abnormal breathing patterns and ventilation. Apneic periods, or pauses in breathing, occur at different frequencies and durations in the sleep cycle depending on the severity of the disorder, resulting in sleep disturbances and a reduction in gas exchange. Consequently, cardiovascular issues may develop because of repeated oxygen-starvation in the body, as well as a range of behavioral health problems brought on by persistent interruptions in the sleep cycle.
Plethysmography utilizes a non-invasive technique which allows conscious polysomnography, or sleep studies, in unanaesthetized, spontaneously breathing subjects. This technique provides continuous high-fidelity respiratory recordings during sleep and wakefulness based on measures of tidal volume, respiratory rate, and minute ventilation.
Integration of electroencephalogram (EEG) & electromyography (EMG) recordings with respiratory signals offer a detailed characterization of the cardiopulmonary contributions in a sleep-disordered breathing state. Plethysmography systems may also integrate with a mass flow controller to measure these respiratory effects under chronic intermittent periods of hypoxia, a key feature of sleep apnea.