Alzheimer's disease and related syndromes have become a major public health priority issue in France. Pharmacological treatments are ineffective and symptomatic, and only delay the progression of the disease.~The management of Alzheimer's disease involves the development of multi-domain prevention programs, including physical activity and neurostimulation by cognitive stimulation. They aim to delay the appearance of fragility defined according to Fried by difficulties in walking, weight loss, fatigue, lack of wrist strength and sedentary lifestyle.~Transcranial direct current stimulation (tDCS) is a stimulation technique using a low intensity DC electric current that acts by modulating neuronal excitability at the cerebral level.~According to recent data, by its action on the cerebral cortex, this simple and non-invasive stimulation technique could prevent the effects of pathological aging, and reduce the cognitive difficulties of the elderly concerning episodic memory, attention and executive functions. These difficulties are also factors related to the risk of the elderly falling (defined by the slowness of walking speed, reduced monopodal support time and the existence of a falling antecedent).~TDCS is a rapidly expanding technique, used to treat cognitive difficulties associated with many pathologies (Parkinson's disease, rehabilitation after head trauma, etc.), but which remains of the field of research.~Its use remains very experimental, and concerns the exploration of cognitions, in healthy and diseased subjects. There are not many studies on the elderly subject with Alzheimer's disease, nor do they document the medium- and long-term effect (more than one month), nor the effect on geriatric parameters such as Fragility indices and the risk of falls, especially at home. These characteristics are decisive because they define the level of autonomy.~The investigators therefore wish to study the effect of a 2-week treatment with tDCS (tDCS active) versus placebo (2-week tDCS group) on these criteria. This effect may stop or curb cognitive decline.
TDCS is a rapidly expanding technique, used to treat cognitive difficulties associated with many pathologies (Parkinson's disease, rehabilitation after head trauma, etc.), but which remains of the field of research.~Its use remains very experimental, and concerns the exploration of cognitions, in healthy and diseased subjects. There are not many studies on the elderly subject with Alzheimer's disease, nor do they document the medium- and long-term effect (more than one month), nor the effect on geriatric parameters such as Fragility indices and the risk of falls, especially at home. These characteristics are decisive because they define the level of autonomy.~The investigators therefore wish to study the effect of a 2-week treatment with tDCS (tDCS active) versus placebo (2-week tDCS group) for a three-month period.