Monitoring differences in the function of the autonomic nervous system in patients with chronic insomnia using a wearable device.

STUDY OBJECTIVES: to characterize possible differences in the function of the ANS in patients with chronic insomnia compared to a control group, using a wearable device, in order to determine whether those findings allow diagnosing this medical entity. METHODS: Thirty-two patients with chronic insomnia and nineteen patients without any sleep disorder, as a control group, were recruited prospectively. Both groups of patients underwent an in-patient night with simultaneous polysomnography and wearable device recording Empatica E4 a diverse array of physiological signals, including electrodermal activity, temperature, accelerometry, and photoplethysmography, providing a comprehensive resource for in-depth sleep analysis. RESULTS: In polysomnography, patients suffering from insomnia showed a significant decrease in sleep efficiency and total sleep time, prolonged sleep latency, and increased wakefulness after sleep onset. Accelerometry results were statistically significant differences in the three axis (x, y, z) just in stage N3, no differences were observed between both groups in REM sleep. The lowest temperature was reached in REM sleep in both groups. Peripheral temperature did not decrease during the different sleep phases compared to wakefulness in insomnia, unlike in the control group. Heart rate was higher in patients with insomnia than in controls during wakefulness and sleep stage. Heart rate variability was lower in stage N3 and higher in REM sleep compared to wakefulness in both groups. Sweating was significantly higher in patients with insomnia compared to the control group, as indicated by Skin Conductance Variability values and Sudomotor Nerve. CONCLUSIONS: Our study suggests that patients with insomnia have increased sympathetic activity during sleep, showing a higher heart rate. Temperature and sweating significantly influence the different sleep phases.

Diagnostic value of vestibular evoked myogenic potentials in benign paroxysmal positional vertigo.

OBJECTIVES: Vestibular evoked myogenic potentials (VEMPs) are useful for studying the disturbances along nerve pathways implicated in the transmission of neurological information from otolithic organs related to vestibular function. This study aims to determine the differences in VEMPs in patients affected with benign paroxysmal positional vertigo (BPPV). METHODS: We recruited 36 patients, 9 diagnosed with recurrent BPPV (rBPPV), 9 with only one episode of vertigo (iBPPV), and 18 as a control group. We performed cervical and ocular VEMPs (cVEMPs and oVEMPs). RESULTS: We observed differences in asymmetry ratio, which was 41.82% in cVEMPs in iBPPV and 68.27% in oVEMPs in rBPPV, while no asymmetry was found in control cases. Also, there was a lack of both VEMP responses in 22.2% of cases and an absence of cVEMP in 11.1% in iBPPV; in rBPPV, 11.1 % presented no responses in cVEMPs or oVEMPs, 22.2% showed no oVEMP, and 11.1% showed no cVEMP. These values were normal in the control group. CONCLUSION: The value of VEMPs in BPPV demonstrates the implication of vestibular damage, mainly utricle damage. For better sensitivity in detecting otolith abnormalities, we should perform oVEMPs and cVEMPs in recurrent BPPV and early stages of BPPV.

Diagnostic Assessment of Respiratory and Hemodynamic Changes Related to Prone Position in COVID-19 Patients.

OBJECTIVE: To study the respiratory patterns and the hemodynamic variations related to postural changes in inpatients with coronavirus disease (COVID-19). METHODS: This report is a prospective study in a cohort of inpatients admitted with COVID-19. We recruited 10 patients admitted to the hospital with moderate or severe COVID-19 who showed improvement in oxygen saturation with prone positioning. We performed cardiorespiratory polygraphy and hemodynamic evaluations by thoracic electrical bioimpedance. RESULTS: We observed a median minimum oxygen saturation of 85.00% (IQR: 7.00) in the supine position versus 91.00% (IQR: 8.00) (P = 0.173) in the prone position. The airflow restriction in the supine position was 2.70% (IQR: 6.55) versus 1.55% (IQR: 2.80) (P = 0.383) in the prone position. A total of 36.4% of patients were classified as having a normo-hemodynamic state in the supine position, whereas 54.5% were classified in this group in the prone position (P = 0.668). A decrease in vascular resistance was observed in the prone position (18.2% of vasoconstriction) compared to the supine position (36.4% of vasoconstriction) (P = 0.871). CONCLUSION: This brief report describes the effects of prone positioning on respiratory and hemodynamic variables in 10 patients with moderate or severe COVID-19.

Diaphragm impairment in patients admitted for severe COVID-19.

Among patients affected by the virus COVID-19, physicians have observed ventilation disorders. It is relevant to assess neurological involvement, including the role of diaphragmatic function. Its possible impairment could be related to the systemic inflammatory response and disease progression that both typify COVID-19 infection. We distinguished two groups (severe group (SG) and mild group (MG)) according to the severity of respiratory symptomatology. We performed neurophysiological and sonography studies to evaluate the diaphragmatic function. Regarding the sonography variables, we identified statistically significant differences in the right mean diaphragmatic thickness along with the expiration, showing 1.56 mm (SEM: 0.11) in the SG vs 1.92 mm (SEM: 0.19) in the MG (p = 0.042). The contractibility of both hemidiaphragms was 15% lower in the severe group, though this difference is not statistically significant. In our examination of the neurophysiological variables, in the amplitude responses, we observed a greater difference between responses from both phrenic nerves as follows: the raw differences in amplitude were 0.40 µV (SEM: 0.14) in the SG vs 0.35 µV (SEM: 0.19) in the MG and the percentage difference was 25.92% (SEM: 7.22) in the SG vs 16.28% (SEM: 4.38%) in the MG. Although diaphragmatic dysfunction is difficult to detect, our combined functional and morphological approach with phrenic electroneurograms and chest ultrasounds could improve diagnostic sensitivity. We suggest that diaphragmatic dysfunction could play a relevant role in respiratory disturbance in hospitalised patients with severe COVID-19.

Myasthenia Gravis Related to Small Cell Lung Carcinoma.

Myasthenia gravis is a neuromuscular disease that causes weakness in skeletal muscles because of the presence of acetylcholine receptor antibodies. These antibodies produce a compromise in the end-plate potential, reducing the safety factor for effective synaptic transmission. Clinically, this manifests as muscle weakness and, in severe cases, respiratory failure. There is widespread knowledge about the association between small cell lung carcinoma and Lambert- Eaton myasthenic syndrome, but not with other neuromuscular disorders, such as myasthenia gravis. We present a patient with small cell lung carcinoma who presented weakness affecting the proximal muscles over the last three years, and electromyography findings suggesting myasthenia gravis. After this electrodiagnosis, analytical tests showed an increase in anti-acetylcholine receptor antibodies. Given these findings, we can affirm that neurophysiological tests provide a significant value in diagnosing myasthenia gravis, as anti-acetylcholine receptor antibodies were negative at the moment of the electromyography's performance. Likewise, it is essential to consider a paraneoplastic syndrome in this type of carcinoma.

What Do Changes in Brain Perfusion Induced by Etomidate Suggest about Epilepsy in Human Patients?

Epilepsy is one of the major neurological disorders, affecting roughly 1-2% of the world's population, of which approximately 20-25% of patients are drug resistant. A variety of drugs have been used to activate and identify the epileptic area in patients during presurgical evaluation. We studied the cerebral blood flow (CBF) by single photon-emission computed tomography (SPECT) and bioelectrical brain activity responses to etomidate in 11 patients. Etomidate (0.1 mg/kg) was administered while patients were monitored by video-electroencephalography with foramen ovale electrodes (FOEs). After etomidate administration, a brief period of high-frequency activity was observed, followed by a generalized, high-voltage delta pattern. Increased regional CBF was observed bilaterally in thalamus, putamen, and posterior hippocampus. Besides, the only interhemispheric difference was observed in the posterior hippocampus, where CBF decreased in the epileptic temporal lobe. Activation by etomidate induces a specific and repetitive response in the bioelectrical activity. In addition, CBF changes induced by etomidate may serve as a diagnostic tool in the near future.