Can non-invasive neurostimulation prevent age-related cognitive decline, including Alzheimer's Disease?
WHAT IS ALZHEIMER’S DISEASE?
Alzheimer’s is a disease characterized by progressive neurodegenerative disorder and is also accountable for dementia (cognitive/memory decline) in old people. According to statistics from 2010, people who had dementia due to Alzheimer’s Disease (AD), at the age of about 60, was 4.02%, and it has been projected to increase drastically by 2030. Treating AD is very costly, with overall spending estimated to be around $422 billion in 2009. Presently, basic pharmacological treatments available for AD patients are N-methyl-D-aspartate receptor partial antagonist and cholinesterase inhibitors. But since these treatments have extremely bad side effects and limited response there is a dire need of alternative treatments for AD.
Transcranial Direct/Alternating Current Stimulation In Treating Alzheimer
Since treatments presently available for AD are not really appreciably effective, scientists have recently figured out that brain stimulation is another considerable alternative as a clinical treatment of Alzheimer’s. Non-invasive transcranial direct current stimulation of the brain has been proved to be one of those methods in treating and preventing Alzheimer’s Disease. It also has considerably better results than other treatment options. To date, tDCS has shown beneficial effects in treating several other diseases as well.
- tDCS Improves Mini-Mental State Examination Score in AD Patients:
A number of experiments have reportedly observed improved cognitive functions of patients with AD. In one of the experiments carried out in Egypt, Khedr and colleagues randomly divided 34 participants, suffering from AD, in 3 groups. Participants of cathodal and anodal groups, both, underwent daily tDCS continuously for 10 days with a low current intensity of 2 mA given to them for about 25 mins/day. A significant improvement was observed on the MMSE score after the experiment, which lasted for about 10 days.
- tDCS improves Visual Recognition in AD patients:
Similarly, Boggio and colleagues have been reported to demonstrate that tDCS used on the temporal cortex and left DLPFC enhanced VRM (Visual Recognition Memory) of patients with Alzheimer’s Disease. Ten AD patients were enrolled by the researchers for this experiment, who received two real stimulations and one sham stimulation (stimulation that uses placebo effects). Real stimulation was incited on left DLPFC with a low current intensity of 2 mA for a time period of 30 seconds/session, whereas, the sham stimulation was only carried out for the first 30 seconds. Neurophysiological tests were generated during tDCS stimulation in which it was found that VRM tasks were significantly improved when tDCS was given over left DLPFC and temporal cortex. After which the tDCS was applied bilaterally over the temporal regions through anodal electrodes on the scalp. This was done for 5 days in a week and the current intensity was kept at 2mA for 30 mins a day. The results were observed after the 5-day treatment and it was found that VRM was actually enhanced to great extent, lasting for almost 1 month.
- tDCS improves Memory Conditions in AD patients:
Likewise, another experiment was carried out by Cotelli and colleagues. A therapy of anodal tDCS with computerized memory training was developed by them. 36 patients with AD were randomly assigned into three groups. The first group was made to go through anodal tDCS along with computerized memory training, while the second group was given placebo tDCS with computerized memory training. The third group was given motor training and anodal tDCS. The tDCS stimulation was generated for 5 days a week, 25 mins/day with a current intensity of 2 mA. The results showed remarkable improvement.
Most of these clinical experiments were small, so conditions and outcomes of stimuli were different, due to which the results also differ from study to study.
Studies are continuously investigating techniques of brain stimulation as a therapeutic treatment of AD. Although, some researches and experiments have given the best of the results, there is much more that still needs to be discovered. However, stimulations that enhance memory and cognitive memory are very effective and promising. Other than this, stimulations targeted at different regions of the brain combined with treatments like cognitive training are reported to produce more positive and good results. Although the field of tDCS is still immature, because it is safe, tolerable, and economic for patients with AD, the studies show that the use of tDCS have grown in decades.
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