This study aimed to measure the spectral power differences in the brain rhythms among a group of hospital doctors before and after an overnight on-call duty. Thirty-two healthy doctors who performed regular on-call duty in a tertiary hospital in Sarawak, Malaysia were voluntarily recruited into this study. All participants were interviewed to collect relevant background information, followed by a self-administered questionnaire using Chalder Fatigue Scale and electroencephalogram test before and after an overnight on-call duty. The average overnight sleep duration during the on-call period was 2.2 hours (p<0.001, significantly shorter than usual sleep duration) among the participants. The mean (SD) Chalder Fatigue Scale score of the participants were 10.8 (5.3) before on-call and 18.4 (6.6) after on-call (p-value < 0.001). The theta rhythm showed significant increase in spectral power globally after an overnight on-call duty, especially when measured at eye closure. In contrast, the alpha and beta rhythms showed reduction in spectral power, significantly at temporal region, at eye closure, following an overnight on-call duty. These effects are more statistically significant when we derived the respective relative theta, alpha, and beta values. The finding of this study could be useful for development of electroencephalogram screening tool to detect mental fatigue.
Previous studies have shown that pharyngeal elevation training can improve swallowing function in stroke patients, but the central nervous system interventions have limited effects. Intermittent theta burst stimulation (iTBS) applied to bilateral cerebellar hemispheres may enhance cortical excitability. However, the efficacy and underlying mechanisms of combining bilateral cerebellar iTBS with real-time biofeedback-guided pharyngeal elevation training for post-stroke dysphagia remain unclear. This study aims to investigate the combined effect of bilateral cerebellar iTBS and biofeedback-guided pharyngeal elevation training on swallowing function and cortical activity in stroke patients during the recovery phase. Methods: 45 stroke patients were randomized into the Control, Sham-iTBS + SET, or Active-iTBS + SET groups (n = 15 each). The latter two groups received additional interventions: Sham or active bilateral cerebellar iTBS combined with swallowing exercises. 42 participants (n = 14 per group) completed the study and were included in the final analysis, following 3 dropouts (n = 1 per group). Swallowing function was assessed using the Standardized Swallowing Assessment (SSA) and Penetration-Aspiration Scale (PAS) before and after 4 weeks of treatment. Functional near-infrared spectroscopy (fNIRS) recorded cortical activation during tasks and resting-state functional connectivity. After 4 weeks of intervention, all groups demonstrated significant improvements in the primary outcome (SSA) and the secondary behavioral outcome (PAS) scores (p
Mitragynine is the major psychoactive alkaloid of the plant kratom/ketum. Kratom is widely used in Southeast Asia as a recreational drug, and increasingly appears as a pure compound or a component of 'herbal high' preparations in the Western world. While mitragynine/kratom may have analgesic, muscle relaxant and anti-inflammatory effects, its addictive properties and effects on cognitive performance are unknown. We isolated mitragynine from the plant and performed a thorough investigation of its behavioural effects in rats and mice. Here we describe an addictive profile and cognitive impairments of acute and chronic mitragynine administration, which closely resembles that of morphine. Acute mitragynine has complex effects on locomotor activity. Repeated administration induces locomotor sensitization, anxiolysis and conditioned place preference, enhances expression of dopamine transporter- and dopamine receptor-regulating factor mRNA in the mesencephalon. While there was no increase in spontaneous locomotor activity during withdrawal, animals showed hypersensitivity towards small challenging doses for up to 14 days. Severe somatic withdrawal signs developed after 12 hours, and increased level of anxiety became evident after 24 hours of withdrawal. Acute mitragynine independently impaired passive avoidance learning, memory consolidation and retrieval, possibly mediated by a disruption of cortical oscillatory activity, including the suppression of low-frequency rhythms (delta and theta) in the electrocorticogram. Chronic mitragynine administration led to impaired passive avoidance and object recognition learning. Altogether, these findings provide evidence for an addiction potential with cognitive impairments for mitragynine, which suggest its classification as a harmful drug.