Mild cognitive impairment in Parkinson's disease is improved by transcranial direct current stimulation combined with physical therapy.

BACKGROUND: Parkinson's disease (PD) is characterized by both motor and cognitive deficits. In PD, physical exercise has been found to improve physical functioning. Recent studies demonstrated that repeated sessions of transcranial direct current stimulation led to an increased performance in cognitive and motor tasks in patients with PD. OBJECTIVES: The present study investigated the effects of anodal transcranial direct current stimulation applied over the dorsolateral prefrontal cortex and combined with physical therapy in PD patients. METHODS: A total of 20 patients with PD were assigned to 1 of 2 study groups: group 1, anodal transcranial direct current stimulation plus physical therapy (n = 10) or group 2, placebo transcranial direct current stimulation plus physical therapy (n = 10). The 2 weeks of treatment consisted of daily direct current stimulation application for 25 minutes during physical therapy. Long-term effects of treatment were evaluated on clinical, neuropsychological, and motor task performance at 3-month follow-up. RESULTS: An improvement in motor abilities and a reduction of depressive symptoms were observed in both groups after the end of treatment and at 3-month follow-up. The Parkinson's Disease Cognitive Rating Scale and verbal fluency test performances increased only in the anodal direct current stimulation group with a stable effect at follow-up. CONCLUSIONS: The application of anodal transcranial direct current stimulation may be a relevant tool to improve cognitive abilities in PD and might be a novel therapeutic strategy for PD patients with mild cognitive impairment. © 2016 International Parkinson and Movement Disorder Society.

Grey Matter Density Predicts the Improvement of Naming Abilities After tDCS Intervention in Agrammatic Variant of Primary Progressive Aphasia.

Agrammatic variant primary progressive aphasia is a neurodegenerative disorder specifically characterized by language deficits. A recent study has demonstrated a beneficial effect of transcranial direct current stimulation (tDCS) in combination with language training on naming accuracy in these patients. The aim of the study was to evaluate whether the improvement of naming accuracy after tDCS during language training was related to regional grey matter (GM) density. Eighteen avPPA patients underwent a brain magnetic resonance imaging before receiving a treatment that consisted of tDCS over the left dorsolateral prefrontal cortex during individualized language training (10 daily therapy sessions, 5 days per week from Monday to Friday). Performances on neuropsychological tests and naming of objects (treated and untreated) and actions were assessed at baseline, post-treatment  and 3 months after treatment. Correlations between individual changes after treatment on neuropsychological tests and on picture naming task and voxel-based GM volume at baseline were performed. We found that the improvement in the naming of treated objects was positively correlated with GM volume in the left fusiform, left middle temporal, and right inferior temporal gyri whereas action naming change was related to GM density in the left middle temporal gyrus. In conclusion baseline density of GM in these brain regions was associated with greater treatment response on naming performances, suggesting that intervention in early disease stages might be most successful. These findings have implication for designing future rehabilitation protocols in language variants of frontotemporal dementia.

Efficacy of semantic-phonological treatment combined with tDCS for verb retrieval in a patient with aphasia.

Recent studies reported enhanced performance on language tasks induced by transcranial direct current stimulation (tDCS) in patients with aphasia. One chronic patient with non-fluent aphasia received 20 sessions of a verb anomia training combined with off-line bihemispheric tDCS applied to the dorsolateral prefrontal cortex (DLPFC) - anodal tDCS over left DLPFC plus cathodal tDCS over right DLPFC. A significant improvement in verb naming was observed at all testing times (4, 12, 24, and 48 weeks from post-entry/baseline testing) for treated and untreated verbs. Our findings show beneficial effects of verb anomia training in combination with tDCS in chronic aphasic patient, suggesting a long-lasting effect of this treatment.

Anodal tDCS during face-name associations memory training in Alzheimer's patients.

OBJECTIVE: Given the limited effectiveness of pharmacological treatments, non-pharmacological interventions to treat Alzheimer's disease (AD) have gained attention in recent years. The aim of the present study is to investigate the effects of anodal tDCS (AtDCS) combined with memory training on face-name associations in an AD patient sample. METHODS: Thirty six AD patients were randomly assigned to one of three study groups: Group 1, AtDCS plus individualized computerized memory training; Group 2, placebo tDCS plus individualized computerized memory training; Group 3, AtDCS plus motor training. RESULTS: A general improvement in performance was observed after 2 weeks of memory training. Both the anodal tDCS plus individualized computerized memory training and the placebo tDCS plus individualized computerized memory training groups had significantly improved performances at 2 weeks compared with the AtDCS plus motor training group. CONCLUSION: Our findings suggest a beneficial effect of individualized memory rehabilitation in AD patients.

Treatment of primary progressive aphasias by transcranial direct current stimulation combined with language training.

BACKGROUND: Primary progressive aphasia (PPA) is an untreatable neurodegenerative disorder that disrupts language functions. Previous studies have demonstrated transcranial direct current stimulation (tDCS) may improve language symptoms in patients with post stroke aphasia or neurodegenerative diseases. OBJECTIVE: The present study investigated whether the application of anodal tDCS (AtDCS) to the scalp overlying the left dorsolateral prefrontal cortex (DLPFC), which may increase cortical excitability, in combination with individualized speech therapy would improve naming accuracy in the agrammatic variant of PPA (avPPA). METHODS: Sixteen avPPA patients were randomly allocated into two subgroups: AtDCS (n = 8) or placebo tDCS (PtDCS). tDCS was applied over the left DLPFC (BA 8/9) 25 minutes per day for two weeks (10 days). Each patient underwent 25 minutes of individualized speech therapy with either AtDCS or PtDCS during each treatment session. Neuropsychological assessment, experimental naming, and linguistic abilities in daily living were assessed at baseline (T0), after two weeks of intervention (T1) and at a 12-week follow-up (T2). RESULTS: Significant improvement in experimental naming was observed in both groups at T1 and T2, but this effect was significantly greater in AtDCS than PtDCS patients. Naming correctness, as assessed using the Aachener Aphasie Test, increased selectively in the AtDCS group from T0 to T1, and this effect remained significant at T2. The analysis of daily living language abilities improved selectively in AtDCS group. CONCLUSION: Our results support the beneficial effect of targeted language training in combination with brain stimulation in avPPA patients. tDCS should be considered a useful tool for the improvement of language functions in patients with neurodegenerative diseases in future trials.

Enhancing verbal episodic memory in older and young subjects after non-invasive brain stimulation.

Memory is the capacity to store, maintain, and retrieve events or information from the mind. Difficulties in verbal episodic memory commonly occur in healthy aging. In this paper, we assess the hypothesis that anodal transcranial direct current stimulation (tDCS) applied over the dorsolateral prefrontal cortex (DLPFC) or over the parietal cortex (PARC) could facilitate verbal episodic memory in a group of 32 healthy older adults and in a group of 32 young subjects relative to a sham stimulation using a single-blind randomized controlled design. Each participant underwent two sessions of anodal tDCS (left and right) and one session of sham stimulation. Overall, our results demonstrated that, in young and in older subjects, anodal tDCS applied during the retrieval phase facilitates verbal episodic memory. In particular, we found that tDCS applied over the left and right regions (DLPFC and PARC) induced better performance in young participants; only tDCS applied over the left regions (DLPFC and PARC) increased retrieval in older subjects. These results suggest that anodal tDCS can be a relevant tool to modulate the long-term episodic memory capacities of young and older subjects.

Compensatory networks to counteract the effects of ageing on language.

BACKGROUND: Word-retrieval difficulties are a common consequence of healthy ageing and are associated with a reduction in asymmetrical recruitment of the dorsolateral prefrontal cortex (DLPFC), although the significance of this reduction has not yet been clarified. Using repetitive transcranial magnetic stimulation (rTMS) it has been demonstrated that an asymmetrical involvement of the DLPFC during action naming in young subjects, whereas bilateral involvement was shown in elderly participants. By using rTMS during a naming task in a group of elderly subjects, the aim of the present work was to investigate whether the magnitude of DLPFC asymmetry (left-right rTMS effect) during action naming correlates with task performance, proving the presence of a compensation strategy in some but not all elderly participants. METHODS: We aimed to test if there was a correlation between DLPFC asymmetry (left-right rTMS effect) and naming performance in a group of elderly subjects. RESULTS: The results show that rTMS affects action naming differently according to individual naming ability. In particular, the predominance of a left vs. right DLPFC effect was observed only in the low-performing older adults, while an asymmetric reduction was selectively shown in the high-performing group. Interestingly, high-performing older adults also displayed better performances on a phonemic fluency test. CONCLUSION: The present data suggest that successful ageing is linked to less prefrontal asymmetry, an efficient strategy for counteracting age-related declines in cognitive function.