The effect of hypoxia on interoception in patient with obstructive sleep apnea.

PURPOSE: Obstructive Sleep Apnea (OSA) is the most common sleep-related disorder. Interoception is the collection of sensory and cognitive processes that involve receiving and interpreting physiological signals from internal body structures and conveying the perception of inner sensations. In this study, it was hypothesized that the impairment in cognitive functions associated with chronic hypoxemia and the insular effects due to OSA would negatively affect interoceptive functions. The aim of this study was to evaluate whether interoception in OSA changes consistent with the hypothesis. METHODS: A total of 102 patients diagnosed with OSA were included in this study. All participants were divided into groups based on their T90 values: desaturated OSA (T90 ≥ 20%) and non-desaturated OSA (T90 < 20%). The Heartbeat Counting Task was used to assess interoceptive accuracy, while the Interoceptive Sense Questionnaire (ISQ) was employed to identify subjective challenges in evaluating interoception. RESULTS: Interoceptive accuracy was lower in the desaturated OSA group than in the non-desaturated OSA group (Z = -2.463; p = 0.014). Interoceptive accuracy was negatively correlated with the body mass index (r = -0.228; p = 0.021), T90 (r = -0.269; p = 0.006), and positively correlated with the average SaO2 (r = 0.377; p < 0.001) and SaO2 nadir (r = 0.243; p = 0.014). CONCLUSION: This study examined interoceptive functions in patients with OSA. It was concluded that interoceptive accuracy is affected by the severity of hypoxia as hypothesized.

The effects of Vagal Nerve Stimulation on time perception in epilepsy patients.

In this study, it was aimed to investigate the effects of switching off stimulation on time perception in patients with drug-resistant epilepsy who underwent Vagal Nerve Stimulation (VNS). In accordance with the literature, a cognitive battery of tests for motor timing and perceptual timing was utilized. Computerized time perception tests; Paced Motor Timing Test, Duration Discrimination Test, Temporal Reproduction Test, and Time Estimation Test were administered to the patients while VNS was on and off. A total of 14 patients who met the inclusion criteria of 23 VNS patients followed in the Epilepsy Outpatient Clinic were included in the study. In the Temporal Reproduction Test, for time durations of 1000 ms (ms), 2000 ms, 3000 ms, 4000 ms, and 5000 ms the comparison of reported time values between VNS on and VNS off yielded respective p values; p = 0.73, p = 0.03, p = 0.176, p = 0.418, p = 0,873. The reported time is thus significantly shorter only for 2000 ms when the VNS was on. Positive effect of VNS on attention, alertness and focusing are expected to cause acceleration of the internal clock resulting in perceiving time running slower than actual. In our study, it was concluded that the internal clock runs faster when the VNS is on, and time is perceived as running slower than it actually is. This result can also be accepted as an indirect indicator of increased attention in the period when VNS is on.