Diagnosis and treatment of mild cognitive impairment and Alzheimer's disease using Transcranial magnetic stimulation/repetitive TMS

Posted on: November 29, 2021

Alzheimer's disease (AD) was reported first by Dr. A. Alzheimer in 1907 in a paper with the title: “A Characteristic Disease of the Cerebral Cortex” (Bick et al., 1987). Since the first semiological description of the symptoms and histological description of the neuronal damage much more has been discovered, ulterior research has focused in tau tangling and amyloid accumulation in the neurons.

Increasing evidence have demonstrated that treatments for AD must be administered early in its appearance, therefore development of diagnostic tools capable of accurate identification at early stages has become crucial. TMS is becoming an effective tool to discriminate between different forms of neurodegenerative dementia. (Padovani et al., 2018).

In a series of 69 subjects with mild cognitive impairment (MCI) participants were classified as AD MCI or MCI unlikely due to AD (non-AD MCI) the criteria was based on extensive neurological and neuropsychological evaluation, MRI imaging, and cerebrospinal fluid analysis or/and amyloid PET imaging. Paired pulse TMS paradigms were used to assess short interval intracortical inhibition-facilitation (SICI-ICF), dependent on GABAergic and glutamatergic intracortical circuits, respectively, and short latency afferent inhibition (SAI), dependent on cholinergic circuits. The authors reported “a significant impairment of SAI and unimpaired SICI and ICF in AD MCI as compared to non-AD MCI”. Their statistical analysis, showed that the SICI-ICF/SAI index differentiated AD MCI from non-AD MCI with a specificity of 87.9% and a sensitivity of 94.4%. (Padovani et al., 2018).

“TMS can influence brain function if delivered repetitively; rTMS is capable of modulating cortical excitability and inducing long-lasting neuroplastic changes. Preliminary findings have suggested that rTMS can enhance performances on several cognitive functions impaired in AD and MCI” (Nardone et al., 2014)

In a recent systematic review and meta-analysis, Xie et al., reviewed twelve studies (438 participants, 231 in the rTMS group and 207 in the control group) in thirteen randomized, double-blind and controlled trials. Their analysis revealed a significant advantage of rTMS on cognitive improvement compared with the control group. “The results revealed that protocols with 10 Hz repetition frequency and DLPFC as the stimulation site for 20 sessions can already be able to produce cognitive improvement. The cognitive enhancement of rTMS could last for one month after the end of treatment and patients with MCI were likely to benefit more from the rTMS stimulation”.

At Jali Medical we offer innovative technology to further develop AD research. Our rTMS devices from DeyMed and Mag&More cover a wide range of options for clinicians and researchers.

About the author

Francisco Benavides, MD

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