Low-Frequency Repetitive Transcranial Magnetic Stimulation Modulates Evoked-Gamma Frequency Oscillations in Autism Spectrum Disorder

Introduction. It has been reported that individuals with Autism Spectrum Disorder (ASD) have abnormal reactions to the sensory environment and visuo-perceptual abnormalities. Electrophysiological research has provided evidence that gamma band activity (30–80 Hz) is a physiological indicator of the coactivation of cortical cells engaged in processing visual stimuli and integrating different features of a stimulus. A number of studies have found augmented and indiscriminative gamma band power at early stages of visual processing in ASD; this may be related to decreased inhibitory processing and an increase in the ratio of cortical excitation to inhibition. Low frequency or “slow” (≤1HZ) repetitive transcranial magnetic stimulation (rTMS) has been shown to increase inhibition of stimulated cortex by the activation of inhibitory circuits.

Method. We wanted to test the hypothesis of gamma band abnormalities at early stages of visual processing in ASD by investigating relative evoked (i.e., ～100 ms) gamma power in 25 participants with ASD and 20 age-matched controls using Kanizsa illusory figures. In addition, we wanted to assess the effects of 12 sessions of bilateral “slow” rTMS to the dorsolateral prefrontal cortex on evoked gamma activity using a randomized controlled design.

Results. In individuals with ASD evoked gamma activity was not discriminative of stimulus type, whereas in controls early gamma power differences between target and nontarget stimuli were highly significant. Following rTMS individuals with ASD showed significant improvement in discriminatory gamma activity between relevant and irrelevant visual stimuli. We also found significant improvement in the responses on behavioral questionnaires (i.e., irritability, repetitive behavior) as a result of rTMS.

Conclusion. We propose that slow rTMS may have increased cortical inhibitory tone, which improved discriminatory gamma activity at early stages of visual processing. rTMS has the potential to become an important therapeutic tool in ASD treatment and has shown significant benefits in treating core symptoms of ASD with few, if any side effects.     

Effect of an equine-movement therapy program on gait, energy expenditure, and motor function in children with spastic cerebral palsy: a pilot study

The purpose of this study was to evaluate the effects of an 8-week program of hippotherapy on energy expenditure during walking; on the gait dimensions of stride length, velocity, and cadence; and on performance on the Gross Motor Function Measure (GMFM) in five children with spastic cerebral palsy (CP). A repeated-measures within-subjects design was used consisting of two baseline measurements taken 8 weeks apart, followed by an 8-week intervention period, then a posttest. After hippotherapy, all five children showed a significant decrease (X_r²;=7.6, P<0.05) in energy expenditure during walking and a significant increase (X_r²=7.6, P<0.05) in scores on Dimension E (Walking, Running, and Jumping) of the GMFM. A trend toward increased stride length and decreased cadence was observed. This study suggests that hippotherapy may improve energy expenditure during walking and gross motor function in children with CP.     

Electrodiagnostic reference values for upper and lower limb nerve conduction studies in adult populations

Introduction: To address the need for greater standardization within the field of electrodiagnostic medicine, the Normative Data Task Force (NDTF) was formed to identify nerve conduction studies (NCS) in the literature, evaluate them using consensus‐based methodological criteria derived by the NDTF, and identify those suitable as a resource for NCS metrics. Methods: A comprehensive literature search was conducted of published peer‐reviewed scientific articles for 11 routinely performed sensory and motor NCS from 1990 to 2012. Results: Over 7,500 articles were found. After review using consensus‐based methodological criteria, only 1 study each met all quality criteria for 10 nerves. Conclusion: The NDTF selected only those studies that met all quality criteria and were considered suitable as a clinical resource for NCS metrics. The literature is, however, limited and these findings should be confirmed by larger, multicenter collaborative efforts. Muscle Nerve 54 : 371–377, 2016