The Effect of Transcranial Pulsed Current Stimulation at 4 and 75 Hz on Electroencephalography Theta and High Gamma Band Power: A Pilot Study

Transcranial Pulsed Current Stimulation and Social Functioning in Children With Autism: A Randomized Clinical Trial

Importance

Transcranial pulsed current stimulation (tPCS) may improve social functioning and sleep disorders in children with autism spectrum disorder (ASD). Prior trials have been limited by small sample sizes, single-center designs, and often a lack of sham controls.

Objective

To examine the safety and efficacy of tPCS in improving social functioning and sleep disorders in children with ASD.

Design, Setting, and Participants

This multicenter, double-blind, 2-armed, sham-controlled randomized clinical trial, conducted from May 1, 2022, through November 30, 2023, assessed children aged 3 to 14 years with ASD at 8 medical centers in China.

Interventions

Participants underwent daily 20-minute sessions of active tPCS (0.7 mA) or sham tPCS (brief 0.7 mA ramp-up and ramp-down) for 20 sessions over 4 weeks with anode over the right cerebellar hemisphere and cathode over the left dorsolateral prefrontal cortex (12.56-cm2-circular, 4-cm-diameter circular electrodes). Each day after tPCS, all participants received 1 hour of standard therapy.

Main Outcomes and Measures

Social functioning was assessed using the Autism Treatment Evaluation Checklist as the primary outcome. Secondary outcomes included the Autism Behavior Checklist and the Childhood Sleep Habits Questionnaire.

Results

A total of 312 participants (155 in the active group and 157 in the sham group; 248 [79.5%] boys; mean [SD] age, 5.1 [1.6] years; 276 [88.5%] aged 3-6 years and 36 [11.5%] aged 7-14 years) completed the trial. After 20 sessions, the mean Autism Treatment Evaluation Checklist total score improved by 4.13 points (5.8%) in the sham tPCS group and 7.17 points (10.7%) in the active tPCS group. Analysis of covariance showed significantly greater improvement in the active tPCS group (difference, -3.50; 95% CI, -5.56 to -1.43; P < .001). Both treatments were well tolerated.

Conclusions and Relevance

In this randomized clinical trial of prefrontal-cerebellar tPCS in children aged 3 to 14 years with ASD, 20 sessions over 4 weeks improved social functioning and sleep. These findings suggest that tPCS may serve as a viable nonpharmacologic alternative for ASD.

Trial Registration

Chinese Clinical Trial Registry Identifier: ChiCTR2200059118.

The effect of transcranial pulse current stimulation on the accumulation of exercise-induced fatigue in college students after moderate intensity exercise evidence from central and peripheral sources

Objective

To investigate the intervention effect of cranial pulse current stimulator (tPCS) on fatigue accumulation after moderate-intensity exercise by using blood analysis and functional near-infrared spectroscopy, and to analyze the type and magnitude of the fatigue effect of tPCS on fatigue in combination with behavioral performance.

Methods

Ninety healthy college students were randomly and equally divided into an experimental group (Group A) and a control group (Group B), and both groups underwent moderate-intensity training for 7 days. Before and after the experiment, all subjects received physiological, biochemical, behavioral, and subjective fatigue indexes, followed by exercise training, and each day of exercise training was followed by tPCS intervention (stimulus intensity of 1.5 mA, stimulus duration of 20 min) and subjective fatigue scale (RPE) test.

Results

① After the tPCS intervention, the daily RPE scores of group A were smaller than those of group B; ② The values of the indexes oxygenated hemoglobin concentration (Oxy-Hb), deoxyhemoglobin concentration (HHb), testosterone (T), and testosterone-to-cortisol ratio (T/C) of group A did not differ significantly from those of the pre-intervention period, and the values of all the indexes of group B were significantly different from those of the pre-intervention period. ③ After tPCS intervention, the values of Oxy-Hb, T, T/C, and on-attention decreased in Groups A and B, with Oxy-Hb decreasing the most; the values of HHb, total hemoglobin concentration (HbTot), hemoglobin concentration difference (HbDiff), cortisol (C), creatine kinase (CK), and reaction time (RT) increased, with the greatest increase in HbDiff; and the Group A The magnitude of change of each index was smaller than that of Group B. After tPCS intervention, the contribution of central fatigue to the effect of reaction time science was greater than that of peripheral fatigue.

Conclusion

① tPCS can delay the development of central fatigue and peripheral fatigue. ② The effect of tPCS on central fatigue is greater than on peripheral fatigue. ③ The effect of tPCS on reaction timing is mainly realized by changing the state of central fatigue.

Transcranial pulsed current stimulation: A scoping review of the current literature on scope, nature, underlying mechanisms, and gaps

Transcranial pulsed current stimulation (tPCS) is a noninvasive brain stimulation technique that has aroused considerable attention in recent years. This review aims to provide an overview of the existing literature on tPCS, examine the scope and nature of previous research, investigate its underlying mechanisms, and identify gaps in the literature. Searching online databases resulted in 36 published tPCS studies from inception until May 2023. These studies were categorized into three groups: human studies on healthy individuals, human studies on clinical conditions, and animal studies. The findings suggest that tPCS has the potential to modulate brain excitability by entraining neural oscillations and utilizing stochastic resonance. However, the underlying mechanisms of tPCS are not yet fully understood and require further investigation. Furthermore, the included studies indicate that tPCS may have therapeutic potential for neurological diseases. However, before tPCS can be applied in clinical settings, a better understanding of its mechanisms is crucial. Hence, the tPCS studies were categorized into four types of research: basic, strategic, applied, and experimental research, to identify the nature of the literature and gaps. Analysis of these categories revealed that tPCS, with its diverse parameters, effects, and mechanisms, presents a wide range of research opportunities for future investigations.

Exploring sensory, motor, and pain responses as potential side or therapeutic effects of sub-2 mA, 400 Hz transcranial pulsed current stimulation

BACKGROUND

Various brain stimulation devices capable of generating high-frequency currents are readily available. However, our comprehension of the potential side or therapeutic effects associated with high-frequency transcranial pulsed current stimulation (tPCS), particularly concerning the new 400 Hz tPCS device, AscenZ-IV Stimulator, developed by AscenZion Neuromodulation Co. Pte. Ltd. in Singapore, remains incomplete.

OBJECTIVE

This study examines preliminary parameters for the safe and comfortable application of 400 Hz tPCS at intensities below 2 mA.

METHODS

In a cross-sectional study, 45 healthy participants underwent sub-2 mA 400 Hz tPCS to assess sensory, motor, and pain thresholds on the dominant side. Study 1 (N = 15) targeted the primary motor cortex of the right-hand area, while study 2 (N = 30) focused on the back of the right forearm.

RESULTS

Study one showed that increasing the current intensity gradually resulted in no responses at sub-0.3 mA levels, but higher intensities (p < 0.001) induced sensory perception and pain responses. Study two replicated these findings and additionally induced motor responses along with the sensory and pain responses.

CONCLUSION

Despite the theoretical classification of tPCS as a subsensory level of stimulation, and the expectation that individuals receiving this type of current should not typically feel its application on the body, this high-frequency tPCS device generates different levels of stimulation due to the physiological phenomenon known as temporal summation. These novel levels of stimulation could be viewed as either potential "side-effects" of high frequency tPCS or as additional "therapeutic benefits". This dual capacity may position the device as one that generates both neuromodulatory and neurostimulatory currents. Comprehensive comprehension of this is vital for the development of therapeutic protocols that incorporate high-frequency tPCS.

Transcranial Pulsed-Current Stimulation versus Transcranial Direct Current Stimulation in Patients with Disorders of Consciousness: A Pilot, Sham-Controlled Cross-Over Double-Blind Study

Transcranial direct-current stimulation (tDCS) over the prefrontal cortex can improve signs of consciousness in patients in a minimally conscious state. Transcranial pulsed-current stimulation (tPCS) over the mastoids can modulate brain activity and connectivity in healthy controls. This study investigated the feasibility of tPCS as a therapeutic tool in patients with disorders of consciousness (DoC) and compared its neurophysiological and behavioral effects with prefrontal tDCS. This pilot study was a randomized, double-blind sham-controlled clinical trial with three sessions: bi-mastoid tPCS, prefrontal tDCS, and sham. Electroencephalography (EEG) and behavioral assessments were collected before and after each stimulation session. Post minus pre differences were compared using Kruskal-Wallis and Wilcoxon signed-rank tests. Twelve patients with DoC were included in the study (eight females, four traumatic brain injury, 50.3 ± 14 y.o., 8.8 ± 10.5 months post-injury). We did not observe any side-effects following tPCS, nor tDCS, and confirmed their feasibility and safety. We did not find a significant effect of the stimulation on EEG nor behavioral outcomes for tPCS. However, consistent with prior findings, our exploratory analyses suggest that tDCS induces behavioral improvements and an increase in theta frontal functional connectivity.