Neuromodulation of the prefrontal cortex facilitates diet-induced weight loss in midlife women: a randomized, proof-of-concept clinical trial.

BACKGROUND: High body mass index (BMI) is associated with neurocognitive impairments that contribute to overeating and interfere with weight loss efforts. Overweight and obesity at midlife can accelerate neurodegenerative changes and increase the risk of late-life dementia. Noninvasive neuromodulation represents a novel, affordable and scalable approach to improve neurocognitive function in this context. The purpose of this proof-of-concept study was to examine whether transcranial direct current stimulation (tDCS) aimed at enhancing prefrontal cortex activity could enhance weight loss, in combination with a hypocaloric diet, and study underlying mechanisms. METHODS: Overall, 38 women with BMI 25-35 kg/m2 underwent a 4 week randomized, double-blinded, sham-controlled, and parallel-design intervention, during which they received eight sessions of tDCS (n = 18 sham, n = 20 active) in combination with a diet (caloric goal of 20 kcal/kg/day). We evaluated longitudinal changes in body weight, appetite and food craving. In addition, we examined the contribution of cognitive-executive processes via food-modified computerized tasks. RESULTS: We found that the active group had more reduction in body weight than the sham group throughout the study (p = 0.020) and significant weekly weight loss. At 4 weeks, the active group lost 2.32% of initial body weight (sham: 1.29%). Components of subjective appetite and food craving showed a trend toward more reduction in the active group. These changes were paralleled by significant improvements in task performance in the active group, particularly in a dual task that required inhibitory control and working memory (p = 0.007-0.031). Improvement in inhibitory control performance predicted reduction in lack of control overeating, explaining 43.5% of its variance at the end of the study (p = 0.003). No significant adverse effects were observed. CONCLUSIONS: Our results provide proof-of-concept validation of prefrontal-targeted tDCS, combined with a diet, in midlife women with excess body weight, paving the way for larger studies evaluating clinical efficacy and long-term effects of this intervention.

Induced Gamma-Band Activity during Actual and Imaginary Movements: EEG Analysis.

The purpose of this paper is to record and analyze induced gamma-band activity (GBA) (30-60 Hz) in cerebral motor areas during imaginary movement and to compare it quantitatively with activity recorded in the same areas during actual movement using a simplified electroencephalogram (EEG). Brain activity (basal activity, imaginary motor task and actual motor task) is obtained from 12 healthy volunteer subjects using an EEG (Cz channel). GBA is analyzed using the mean power spectral density (PSD) value. Event-related synchronization (ERS) is calculated from the PSD values of the basal GBA (GBAb), the GBA of the imaginary movement (GBAim) and the GBA of the actual movement (GBAac). The mean GBAim and GBAac values for the right and left hands are significantly higher than the GBAb value (p = 0.007). No significant difference is detected between mean GBA values during the imaginary and actual movement (p = 0.242). The mean ERS values for the imaginary movement (ERSimM (%) = 23.52) and for the actual movement (ERSacM = 27.47) do not present any significant difference (p = 0.117). We demonstrated that ERS could provide a useful way of indirectly checking the function of neuronal motor circuits activated by voluntary movement, both imaginary and actual. These results, as a proof of concept, could be applied to physiology studies, brain-computer interfaces, and diagnosis of cognitive or motor pathologies.

User-friendly cognitive training for the elderly: a technical report.

OBJECTIVE: This article presents a system that implements a cognitive training program in users' homes. The system comprises various applications designed to create a daily brain-fitness regime. MATERIALS AND METHODS: The proposed mental training system uses television and a remote control specially designed for the elderly. This system integrates Java applications to promote brain-fitness training in three areas: arithmetic, memory, and idea association. The system comprises the following: Standard television set, simplified wireless remote control, black box (system's core hardware and software), brain-fitness games (language Java), and Wi-Fi-enabled Internet-connected router. All data from the user training sessions are monitored through a control center. This control center analyzes the evolution of the user and the proper performance of the system during the test. RESULTS: The implemented system has been tested by six healthy volunteers. The results for this user group demonstrated the accessibility and usability of the system in a controlled real environment. The impressions of the users were very favorable, and they reported high adaptability to the system. The mean score for usability and accessibility assigned by the users was 3.56 out of 5 points. The operation stress test (over 200 h) was successful. CONCLUSION: The proposed system was used to implement a cognitive training program in users' homes, which was developed to be a low-cost tool with a high degree of user interactivity. The results of this preliminary study indicate that this user-friendly system could be adopted as a form of cognitive training for the elderly.

A computer-aided diagnosis of multiple sclerosis based on mfVEP recordings.

INTRODUCTION: The aim of this study is to develop a computer-aided diagnosis system to identify subjects at differing stages of development of multiple sclerosis (MS) using multifocal visual-evoked potentials (mfVEPs). Using an automatic classifier, diagnosis is performed first on the eyes and then on the subjects. PATIENTS: MfVEP signals were obtained from patients with Radiologically Isolated Syndrome (RIS) (n = 30 eyes), patients with Clinically Isolated Syndrome (CIS) (n = 62 eyes), patients with definite MS (n = 56 eyes) and 22 control subjects (n = 44 eyes). The CIS and MS groups were divided into two subgroups: those with eyes affected by optic neuritis (ON) and those without (non-ON). METHODS: For individual eye diagnosis, a feature vector was formed with information about the intensity, latency and singular values of the mfVEP signals. A flat multiclass classifier (FMC) and a hierarchical classifier (HC) were tested and both were implemented using the k-Nearest Neighbour (k-NN) algorithm. The output of the best eye classifier was used to classify the subjects. In the event of divergence, the eye with the best mfVEP recording was selected. RESULTS: In the eye classifier, the HC performed better than the FMC (accuracy = 0.74 and extended Matthew Correlation Coefficient (MCC) = 0.68). In the subject classification, accuracy = 0.95 and MCC = 0.93, confirming that it may be a promising tool for MS diagnosis. CONCLUSION: In addition to amplitude (axonal loss) and latency (demyelination), it has shown that the singular values of the mfVEP signals provide discriminatory information that may be used to identify subjects with differing degrees of the disease.