Are the EEG microstates correlated with motor and non-motor parameters in patients with Parkinson's disease?

OBJECTIVES: This study compared electroencephalography microstates (EEG-MS) of patients with Parkinson's disease (PD) to healthy controls and correlated EEG-MS with motor and non-motor aspects of PD. METHODS: This cross-sectional exploratory study was conducted with patients with PD (n = 10) and healthy controls (n = 10) matched by sex and age. We recorded EEG-MS using 32 channels during eyes-closed and eyes-open conditions and analyzed the four classic EEG-MS maps (A, B, C, D). Clinical information (e.g., disease duration, medications, levodopa equivalent daily dose), motor (Movement Disorder Society - Unified Parkinson Disease Rating Scale II and III, Timed Up and Go simple and dual-task, and Mini-Balance Evaluation Systems Test) and non-motor aspects (Mini-Mental State Exam [MMSE], verbal fluency, Hospital Anxiety and Depression Scale, and Parkinson's Disease Questionnaire-39 [PDQ-39]) were assessed in the PD group. Mann-Whitney U test was used to compare groups, and Spearman's correlation coefficient to analyze the correlations between coverage of EEG-MS and clinical aspects of PD. RESULTS: The PD group showed a shorter duration of EEG-MS C in the eyes-closed condition than the control group. We observed correlations (rho = 0.64 to 0.82) between EEG-MS B, C, and D and non-motor aspects of PD (MMSE, verbal fluency, PDQ-39, and levodopa equivalent daily dose). CONCLUSION: Alterations in EEG-MS and correlations between topographies and cognitive aspects, quality of life, and medication dose indicate that EEG could be used as a PD biomarker. Future studies should investigate these associations using a longitudinal design.

Can Task Specificity Impact tDCS-Linked to Dual Task Training Gains in Parkinson's Disease? A Protocol for a Randomized Controlled Trial.

Patients with Parkinson's disease (PD) have difficulties while performing dual-task activities, a condition present in everyday life. It is possible that strategies such as transcranial Direct Current Stimulation (tDCS) can be associated with motor training enriched with dual-task training to improve the performance of two concurrent tasks. Currently, it is unclear whether specific tasks and clinical conditions of PD patients have different results after the intervention. Therefore, the proposed randomized controlled trial will examine task-dependency in enhancing the effects of tDCS-linked rehabilitation training on PD and the relationships between baseline outcomes in responders and non-responders to therapy. Fifty-six patients with Parkinson's disease will be recruited to participate in this controlled, double-blind randomized multicentric clinical trial. Patients in modified Hoehn & Yahr stage 1.5-3, age between 40 and 70 years will be included. Subjects will be randomly assigned to an experimental group (EG) and a control group (CG). The EG will perform treadmill gait training associated with dual task exercises+tDCS, while the CG will only engage in treadmill gait training+tDCS. Blinded testers will assess patients before and after 12 intervention sessions and after a 4-week follow-up period. All patients will undergo a screening and an initial visit before being assessed for primary and secondary outcomes. The primary outcome measure is functional mobility measured by Timed Up and Go Test. Secondary outcomes include cognitive function, participation, motor function and body function and structure. This study will evaluate the effectiveness of an intervention protocol with tDCS, dual-task training and gait training in patients with PD. The study will also highlight the clinical factors and variability between individuals that could interfere in the training of a specific task and influence the therapeutic effect. Clinical Trial registration: www.ClinicalTrials.gov, identifier NCT04581590.

Localizing the Primary Motor Cortex of the Hand by the 10-5 and 10-20 Systems for Neurostimulation: An MRI Study.

Background. The primary motor cortex of the hand (M1-Hand) is a target used in transcranial magnetic stimulation (TMS) and in transcranial direct current stimulation (tDCS) for the treatment and evaluation of motor neurological diseases. Magnetic resonance imaging-guided neuronavigation locates the M1-Hand with high precision, but at a high cost. Although less accurate, the C3/C4 points of the international 10-20 system (IS 10-20) are routinely used to locate the M1-Hand. The international 10-5 system (IS 10-5) was developed with additional points (C3h/C4h), which could make it more accurate, but has not yet been tested on the location of the M1-Hand. Objective. To analyze and compare the accuracy of C1/C2, C3h/C4h and C3/C4 points in locating the M1-Hand correspondence on the scalp. Methods. The authors comparatively analyzed the distances from points C1/C2, C3h/C4h, and C3/C4 to the correspondence of the M1-Hand on the scalp in 30 MRI head exams. Results. In most cases, the M1-Hand was located between C1-C3h and C2-C4h in the left and right hemispheres of the brain, respectively. The C3h (0.98 ± 0.49 cm) and C4h (0.98 ± 0.51 cm) points presented the shortest distances from the M1-Hand, with a significant difference when compared with C3/C4. The accuracy between C1/C2 and C3h/C4h was not statistically significant. Conclusion. The C3h/C4h and C1/C2 points were more accurate when compared with the C3 and C4 points in locating the M1-Hand correspondence on the scalp.

Transcranial direct current stimulation associated with gait training in Parkinson's disease: A pilot randomized clinical trial.

OBJECTIVE: The aim of this study is to investigate the effects of transcranial direct current stimulation (tDCS) combined with cueing gait training (CGT) on functional mobility in patients with Parkinson´s disease (PD). METHODS: A pilot double-blind controlled, randomized clinical trial was conducted with 22 patients with PD assigned to the experimental (anodal tDCS plus CGT) and control group (sham tDCS plus CGT). The primary outcome (functional mobility) was assessed by 10-m walk test, cadence, stride length, and Timed Up and Go test. Motor impairment, bradykinesia, balance, and quality of life were analyzed as secondary outcomes. Minimal clinically important differences (MCIDs) were observed when assessing outcome data. RESULTS: Both groups demonstrated similar gains in all outcome measures, except for the stride length. The number of participants who showed MCID was similar between groups. CONCLUSION: The CGT provided many benefits to functional mobility, motor impairment, bradykinesia, balance, and quality of life. However, these effect magnitudes were not influenced by stimulation, but tDCS seems to prolong the effects of cueing therapy on functional mobility.

Dopamine-independent effects of combining transcranial direct current stimulation with cued gait training on cortical excitability and functional mobility in Parkinson's disease.

OBJECTIVE: To investigate the dopamine-dependent effect of combining transcranial direct current stimulation (tDCS) with visually cued gait training on cortical excitability and functional mobility in individuals with Parkinson's disease. DESIGN: A pilot, randomized, double-blind, controlled trial. METHODS: Twenty-two patients with Parkinson's disease were randomly assigned to 2 groups: (i) active anodal tDCS over the supplementary motor area (experimental group), or (ii) sham tDCS (control group). After tDCS, both groups participated in a visually cued gait training. Functional mobility was evaluated with the Timed Up and Go test (TUG). Cortical excitability was assessed by active motor threshold and motor-evoked potential amplitudes elicited by transcranial magnetic stimulation in patients in on and off medication states. RESULTS: In the TUG test both groups achieved improvements either in on or off medication condition compared with baseline. However, for both medication conditions, these gains were maintained only in the experimental group during 1-month follow-up, compared with baseline. In the experimental group, enhancement of cortical excitability was observed at post-intervention and 1-month follow-up (both only for the "on" phase) compared with baseline. CONCLUSION: These findings suggest that tDCS, independent of dopaminergic medication state, might prolong the positive effect induced by cued gait training on functional mobility.

Effects of diode laser (810 nm) irradiation on root canal walls: thermographic and morphological studies.

This study investigated the thermal effects and the morphological changes after diode laser irradiation (810 nm) of root canals. Samples were irradiated at 2.5 W, 1,989 W/cm2 (group 2) and 1.25 W, 10 Hz, 994 W/cm2 (group 3), with group 1 being the control group of nonirradiated samples. The temperature rise was evaluated using an infrared thermographic camera, and the morphological changes were assayed by scanning electron microscopy (SEM). The SEM images revealed closed dentinal tubules, especially at the apical regions when compared with the control samples. The maximum temperature variations at the apical region were analyzed, and the resulting 95% confidence intervals of the medians (Wilcoxon) ranged from 1.6 to 8.6 degrees C (group 2) and from 1.2 to 3.3 degrees C (group 3). The results suggest that the diode laser can be used for endodontic purposes and show that the method is safe for periodontal tissues at the investigated parameters.