Transcranial direct current stimulation enhances theory of mind in Parkinson’s disease patients with mild cognitive impairment:a randomized,double-blind,sham-controlled study

Background:Parkinson’s Disease(PD)with mild cognitive impairment(MCI)(PD-MCI)represents one of the most dreaded complications for patients with PD and is associated with a higher risk of developing dementia.Although transcranial direct current stimulation(tDCS)has been demonstrated to improve motor and non-motor symptoms in PD,to date,no study has investigated the effects of tDCS on Theory of Mind(ToM),i.e.,the ability to understand and predict other people’s behaviours,in PD-MCI.Methods:In this randomized,double-blind,sham-controlled study,we applied active tDCS over the medial frontal cortex(MFC)to modulate ToM performance in twenty patients with PD-MCI.Twenty matched healthy controls(HC)were also enrolled and were asked to perform the ToM task without receiving tDCS.Results:In the patients with PD-MCI,i)ToM performance was worse than that in the HC,ii)ToM abilities were poorer in those with fronto-executive difficulties,and iii)tDCS over the MFC led to significant shortening of latency for ToM tasks.Conclusions:We show for the first time that active tDCS over the MFC enhances ToM in patients with PD-MCI,and suggest that non-invasive brain stimulation could be used to ameliorate ToM deficits observed in these patients.

Language training for oral and written naming impairment in primary progressive aphasia:a review

Background Primary progressive aphasia(PPA)is a neurodegenerative disorder characterized by a gradual,insidious and progressive loss of language abilities,with naming difficulties being an early and persistent impairment common to all three variants.In the absence of effective pharmacological treatments and given the progressive nature of the disorder,in the past few decades,many studies have investigated the effectiveness of language training to minimize the functional impact of word-finding difficulties in daily life.Main body We review language treatments most commonly used in clinical practice among patients with different variants of PPA,with a focus on the enhancement of spoken and written naming abilities.Generalization of gains to the ability to name untrained stimuli or to other language abilities and the maintenance of these results over time are also discussed.Forty-eight studies were included in this literature review,identifying four main types of language treatment:a)lexical retrieval treatment,b)phonological and/or orthographic treatment,c)semantic treatment,and d)a multimodality approach treatment.Overall,language training is able to induce immediate improvements of naming abilities in all variants of PPA.Moreover,despite the large variability among results,generalization and long-term effects can be recorded after the training.The reviewed studies also suggest that one factor that determines the choice of a particular approach is the compromised components of the lexical/semantic processing system.Conclusion The majority of studies have demonstrated improvements of naming abilities following language treatments.Given the progressive nature of PPA,it is essential to apply language treatment in the early stages of the disease.