Multisite transcranial direct current stimulation associated with cognitive training in episodic memory and executive functions in individuals with Alzheimer’s disease: a case report

BACKGROUND: Dementia is among the most common chronic noncommunicable neurodegenerative diseases. In the long term, it causes disability and loss of autonomy and independence. It is estimated that there are 35.6 million people with Alzheimer’s disease worldwide. Several clinical aspects of this disease have been widely studied, but the main focus of study has been memory loss, which is one of the first symptoms. The present study proposes an innovative intervention that combines cognitive training and multisite transcranial direct current stimulation, which interferes with other clinical aspects of the subject. CASE PRESENTATION: In this study, we present two subjects diagnosed with mild Alzheimer’s disease. Subject 1 is an 82-year-old Brazilian Latin American woman with a high school education who was diagnosed with Alzheimer’s disease 8 years ago and uses an Exelon patch. Subject 2 is an 88-year-old Brazilian Latin American woman with an incomplete primary education who was diagnosed with Alzheimer’s disease 1 year ago and received medical orientation to temporarily discontinue medications for Alzheimer’s disease. Both participants were subjected to intermittent cognitive training sessions and concomitant transcranial stimulation in three weekly 30-minute sessions in which a brain area was stimulated every 10 minutes for a total of 24 sessions, with a 2-month follow-up. Transcranial stimulation was applied to six different regions of the cortex: the dorsolateral prefrontal cortex bilaterally, the somatosensory association cortex bilaterally and Broca’s and Wernicke’s areas. Comparing the results of tests performed before and after the treatment period, a 1-point improvement was observed for both subjects on the Word Recall task of the Alzheimer Disease Assessment Scale, which evaluates symptoms related to the decline of episodic memory. Improvement in the executive functions domain was also observed through the results of the Stroop test, Victoria version. CONCLUSIONS: The results from the two presented cases show that multisite transcranial stimulation associated with cognitive training is an effective adjuvant method for the treatment of patients diagnosed with mild Alzheimer’s disease. Its effects can benefit patients’ daily routines by reducing cognitive deficits by keeping intact areas active and/or compensating for lost functions. Trial registration NCT02772185. Registered 13 May 2016, http://www.clinicaltrials.gov/ct2/show/NCT02772185. Retrospectively registered.