As a physical therapist, Hsin-Min Lee has completed his PhD of Biomedical Engineering from the National Cheng– Kung University. Dr. Lee’s research interest focuses on using the knowledge and techniques of engineering to quantify the clinical phenomena (such as muscular spasticity) and to evaluate the neurophysiological effects of clinical treatment (such as massage and mirror therapy). Detection and processing for EMG and EEG signal are the core techniques in his Muscle Electrophysiological Lab. Also he has developed and held the patents of several quantitative systems (for spasticity measurement,and steering movement analysis) and a digital mirror therapy system in Taiwan.
Mirror therapy (MT) has been used in clinics to manage phantom pain or to improve motor recovery of paretic limb for many years. Mirror visual feedback (MVF) during MT was believed to impact the brain to activate certain neural circuits centrally. However, little was known about the MVF effects on peripheral circuits. The feeling of jolt, experienced by most of MT adopters, is an interesting phenomenon that occurred if the movement discrepancy exists between the MVF and the hidden hand. Understanding of jolt feeling on how and what extent the MVF affects peripheral circuit will help us know the mechanism of MT profoundly. In the study, we primarily evaluate the effect of MVF on stretch reflex circuits by measuring H waves. Moreover, movement with extra load was used to know the central effect of MVF on peripheral circuits. Twelve normal participants were included to test three different experimental conditions, i.e. MVF without load (condition 1), MVF with load (condition 2) and no MVF with load (condition 3). Ten maximal H-reflex responses of flexor carpi radialis were recorded during both their right wrist flexion and extension movements under three conditions. The results shown H-reflex amplitudes are significantly larger during wrist flexion than during wrist extension for all conditions (all P<0.05). However, H-reflex amplitudes didn’t significantly different among three conditions for both wrist flexion and extension (all P>0.05). Interlimb neural coupling might dominate the peripheral effects of MVF in current experimental setup. Further study with more subjects and different conditions are warranted. (Up to 250 words)
Peter Riley is a Consultant Medical Physicist employed as a Senior Lecturer for Diagnostic Imaging & Medical Physics, with the School of Medicine at Deakin University, Waurn Ponds. His publications include mathematical modeling of tumour growth and the application of neural networks for computer aided diagnosis in nuclear medicine imaging.
There are numerous diseases of the nervous system which manifest abnormal sleep-wake cycles and there are many explanatory mechanisms identifying various neurochemical species involvements1. The Hobson AIM model2 of brain activation provides a state-space model which includes sleep-wake states, but which does not readily explain the sometimes abrupt transitions between states observed clinically. The presence of abrupt state changes suggests an underlying non-linear mechanism characteristic of a cusp catastrophe. A simple model is proposed which originates from logistic growth of competing neurotransmitters promoting and demoting neural activation with the addition of a scavenging mechanism modeled as a sigmoid process. The model shows potential state trajectories which include: 1. Smoothe transitions from sleep-wake states as a “normal” process. 2. Catastrophic transitions from the wake state to the sleep state, reminiscent of narcolepsy. 3. Catastrophic transitions from the sleep state to the wake state. 4. Rapid cycling between sleep and wake states, reminiscent of delirium. 5. An intermediate bifurcation point which may correspond to the normal NREM state.