Processing in the non-dominant hand during sleep: in terms of early, middle-early and late brain responses.

The aim was to investigate brain responses to non-painful tactile stimuli applied to the non-dominant hand during sleep. 21 healthy subjects participated in the study (11 female, mean age ± SD: 20.67 ± 1.91 years). A 40-channel polysomnography system and a pneumatic tactile stimulator unit were used. Stimuli were applied to the participants' non-dominant hand. Evoked potential components of the CZ electrode were examined in four sleep stages (N1, N2, N3, and REM). Repeated measures ANOVA was used in statistical analyses. Brain responses, categorized as early (P50, N100, and P200), mid-early (N300, P450, and N550), and late (P900 and Nlate), were detected all sleep stages. No notable variances were found in the amplitude and latency of early brain responses when analyzed across different sleep stages. Differences in both amplitude and latency were observed across different sleep stages for the N300, P450, P900, and Nlate response components. This study presents a pioneering exploration into the responses of the non-dominant hand throughout all sleep stages, encompassing eight distinct response components. This novel investigation contributes to the existing literature by shedding light on previously unexplored aspects. The observed early responses are identified as sensory, while middle to late responses align with cognitive processes within the realm of sleep research. Notably, N300, P450, P900, and Nlate components display variations across diverse sleep stages, marked by alterations in both amplitude and latency. These findings offer valuable insights into the dynamic nature of hand responses throughout the sleep continuum.

The effect of Schroth Best Practice exercises and Cheneau brace treatment on perceptual and cognitive asymmetry in adolescent idiopathic scoliosis with thoracic major curve.

BACKGROUND: Adolescent idiopathic scoliosis (AIS) patients have been found to exhibit cortical asymmetry. Although asymmetries in cortical structures have been found in patients with AIS, there has been no research on how conservative treatments affect cerebellar functional organization. AIMS: This study aimed to examine the impact of conservative treatments on perceptual and cognitive asymmetry in the auditory system assessed by dichotic listening in AIS patients with thoracic major curves. METHOD: This study involved 30 AIS patients and 21 healthy subjects. The intervention group used a Cheneau brace and performed 18 Schroth Best Practice (SBP) exercise sessions. Auditory lateralization was assessed using the Dichotic Listening Paradigm (DLP) in both groups before and after the intervention. RESULTS: The 6-week intervention resulted in a significant increase in left ear responses in the force-left condition in the AIS (p < 0.05). Left ear responses were lower in AIS at baseline (p < 0.05). The results at week 6 were similar in all conditions (p > 0.05). CONCLUSION: The results of this study demonstrated that SBP exercises and Cheneau brace treatment can improve perceptual and cognitive asymmetry in the auditory system in AIS patients with thoracic major curve. Scoliosis-associated changes in the spine and postural control may affect auditory perception by causing adaptations in sensory and motor networks. Future studies are needed to examine the connectivity in brain regions related to motor control and auditory processing after conservative treatment. TRIAL REGISTRATION: Clinical trials number: NCT06141759.

Primed Tactile Stimulus Processing during Sleep.

The aim was to investigate how the primed and unprimed non-painful tactile stimuli during sleep would be processed. A total of 22 healthy subjects (19.55 ± 1.10 years) were randomly divided into two groups. The same stimuli were applied to both groups, but the study group (SG) received them twice (daytime and sleep), whereas the control group (CG) received them only during sleep. A 40-channel PSG and a pneumatic tactile stimulator unit were used. Evoked potential components of the CZ electrode were examined in four sleep stages (N1, N2, N3, and REM). The Mann-Whitney U test was used for group comparison, and the Wilcoxon test was used for in-group evaluations. The P50 and N300 response components were observed in all sleep stages in both groups. P50 decreased as sleep deepened in the SG. The N300 increased as sleep deepened and started to decrease again in the REM stage. Moreover, in N1, the amplitudes of P200-N300 and N300-P450 in the SG were significantly greater than those in the CG. The fact that P50 was observed even in N3 indicates that bottom-up sensory processing continues during sleep. Moreover, the central processing of primed and unprimed stimuli exhibited dynamic differences. Furthermore, an increase in N300 amplitude suggests suppressive processes to facilitate and maintain sleep.

Investigation of the perceptual and cognitive asymmetry in the auditory system in patients with adolescent idiopathic scoliosis.

BACKGROUND: Studies have shown that perceptual and cognitive asymmetries are present in the auditory system in patients with adolescent idiopathic scoliosis (AIS). The Dichotic Listening (DL) paradigm was formerly performed in non-forced (NF) conditions only, and no study has examined the conditions of attention to one ear. OBJECTIVE: To investigate the perceptual and cognitive asymmetry in the auditory system in patients with AIS as well as the asymmetry changes according to the curvature characteristics of patients with AIS. METHOD: The DL paradigm was performed on 38 patients with AIS and 10 healthy individuals in all conditions (NF, Forced Right [FR], Forced Left [FL]). RESULTS: In the NF and FL conditions, the mean number of correct responses for the left ear was significantly lower in patients with AIS than in healthy individuals (p < 0.05). The correct responses for the right ear in the NF condition, right and left ear in the FR condition, and right ear in the FL condition did not show a significant difference between the groups (p > 0.05). Also, there was no difference between patients with AIS with both functional 3-curve and 4-curve (p > 0.05). CONCLUSION: Our study indicates perceptual and cognitive asymmetry or lateralisation in the auditory system in patients with AIS. The asymmetry might be caused by the inability to direct their attention to the left ear, which is not affected by their curvature type. Further studies are needed to investigate perceptual and cognitive asymmetry behaviour models in the auditory system in patients with AIS. CLINICAL IMPLICATIONS: Determination of perceptual and cognitive asymmetry in the auditory system may offer a new perspective on conservative treatment protocols for AIS patients. Besides, the DL paradigm can be easily used in patients with AIS as a non-invasive evaluation method in clinics.

Evaluation of the compliance between EEG monitoring (Bispectral IndexTM) and Ramsey Sedation Scale to measure the depth of sedation in the patients who underwent procedural sedation and analgesia in the emergency department.

BACKGROUND: This study aimed to investigate the compliance between electroencephalogram monitoring (Bispectral Index, BIS) and Ramsay Sedation Scale (RSS) to measure the depth of sedation in patients who underwent procedural sedation and analgesia (PSA) in an emergency department. This study also aimed to investigate the usefulness of this compliance for early diagnosis of complications. METHODS: A total of 54 consecutive patients during PSA in the emergency department were included in this study. The BIS and RSS scores at regular intervals and also all complications and interventions of these patients were evaluated. The compliance between the BIS and the RSS score was evaluated. The BIS scores of cases with complication and without complication were compared. RESULTS: The BIS and RSS scores exhibited a high correlation was detected between the average BIS and RSS scores at each time interval (r=-0.989, p<0.001). The BIS scores of the complicated and uncomplicated cases were different at 15 min after the procedure (p=0.019). The cases were divided into two groups according to the BIS scores <70 and ≥70; complication rates were higher in the BIS score <70 group during the procedure (p=0.037). CONCLUSION: In our study, a high correlation was detected between BIS monitoring and RSS scores. BIS monitoring for PSA can be used as a full-time, objective, and an alternative technique for person-dependent clinical scales and also as an indicator for early diagnosis of complications.

Sleep Is a Refreshing Process: An fNIRS Study.

Sleep is a very critical process that constitutes up to one third of daytime of a healthy adult. It is known to be an active period where body and brain is refreshed for the next day. It is both part of a larger cycle, i.e., circadian rhythm, and has subcsycles in it, i.e., sleep stages. Although hemodynamics of these stages have been investigated especially in the last two decades, there are still points in the hemodynamics to be illuminated especially in terms of refreshment. This study aims to investigate refreshing property of sleep in terms of sleep stages using functional near-infrared spectroscopy (fNIRS) for measuring prefrontal cortex (PFC) hemodynamics. Nine healthy subjects slept in sleep laboratories, monitored by polysomnography and fNIRS before, during, and after night sleep. REM stage had lower oxyhemoglobin (HbO) and total hemoglobin (HbT) than the other sleep stages and wakefulness. Deoxyhemoglobin (HbR) did not differ between any stages. All sleep stages and wakefulness stage at the end of the sleep had higher HbO and lower HbR than the beginning of the sleep. HbT levels did not differ between the beginning and the end of the sleep for any stages. During REM sleep, PFC seems to get lower blood supply, possibly due to increased demand in other brain regions. Regardless of the stage, PFC has higher oxygenation toward the end of sleep, indicating refreshment. Overall, our brain seems to be on duty during sleep throughout the night for "cleaning" and "refreshing" itself. Hemodynamic changes from the beginning to end of sleep might be the indicator of this work. Thus, accordingly REM stage seems to be at a central point for this work.