Neuroimaging-Guided Transcranial Magnetic and Direct Current Stimulation in MCI: Toward an Individual, Effective and Disease-Modifying Treatment

Abstract

The therapeutic approaches currently applied in Alzheimer's disease (AD) and similar neurodegenerative diseases are essentially based on pharmacological strategies. However, despite intensive research, the effectiveness of these treatments is limited to transient symptomatic effects, and they are still far from exhibiting a true therapeutic effect capable of altering prognosis. The lack of success of such pharmacotherapy-based protocols may be derived from the cases in the majority of trials being too advanced to benefit significantly in therapeutic terms at the clinical level. For neurodegenerative diseases, mild cognitive impairment (MCI) may be an early stage of the disease continuum, including Alzheimer's. Noninvasive brain stimulation (NIBS) techniques have been developed to modulate plasticity in the human cortex in the last few decades. NIBS techniques have made it possible to obtain unique findings concerning brain functions, and design novel approaches to treat various neurological and psychiatric conditions. In addition, its synaptic and cellular neurobiological effects, NIBS is an attractive treatment option in the early phases of neurodegenerative diseases, such as MCI, with its beneficial modifying effects on cellular neuroplasticity. However, there is still insufficient evidence about the potential positive clinical effects of NIBS on MCI. Furthermore, the huge variability of the clinical effects of NIBS limits its use. In this article, we reviewed the combinatory approach of NIBS with various neuroimaging and electrophysiological methods. Such methodologies may provide a new horizon to the path for personalized treatment, including a more individualized pathophysiology approach which might even define new specific targets for specific symptoms of neurodegenerations.

From Lab to Life: Exploring Cutting-Edge Models for Neurological and Psychiatric Disorders

“…Neuroplasticity encompasses various mechanisms, including synaptic plasticity, neurogenesis, and alterations in neuronal connectivity, which underpin crucial processes such as learning, memory, and recovery from injury or disease [ 17 , 18 , 19 , 20 ]. In tandem with understanding neuroplasticity, non-invasive brain stimulation (NIBS) techniques such as transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS) have emerged as promising therapeutic modalities [ 21 , 22 , 23 ]. These techniques can modulate neuroplasticity by inducing changes in cortical excitability and connectivity, offering potential avenues for ameliorating symptoms associated with conditions such as depression, schizophrenia (SCZ), and chronic pain [ 24 , 25 , 26 ].…”

Cognitive training and brain stimulation in patients with cognitive impairment: a randomized controlled trial

“…In this context, pairing a cognitive training intervention with an NIBS technique such as transcranial direct current stimulation (tDCS) has been suggested to be an attractive, safe, and beneficial treatment option [ 4 ]. Combined with training, tDCS increases cortical excitability by changing membrane potentials toward depolarization, tuning ongoing neural processes, and promoting long-term-potentiation-like synaptic plasticity [ 6 ].…”

“…Beyond immediate effects of the intervention, some studies have observed partially sustained improvements in working memory functions in healthy adults [ 11 – 13 ]. In patients with cognitive impairment and dementia due to AD, reports of beneficial effects remain limited and heterogeneous [ 4 , 14 , 15 ]. Two randomized controlled trials in patients with early stages of cognitive impairment (such as MCI or mild AD) have reported improved cognitive performance after combined tDCS and training interventions [ 16 , 17 ], while two others did not find intervention benefits [ 18 , 19 ].…”

Predicting the Effects of Repetitive Transcranial Magnetic Stimulation on Cognitive Functions in Patients With Alzheimer's Disease by Automated EEG Analysis

“…Transcranial magnetic stimulation (TMS), which has long been used successfully in the treatment of depression (Sonmez et al, 2019 ), is now being employed as a possible alternative treatment for other neurodegenerative diseases such as Alzheimer's disease (Freitas et al, 2011 ; Mimura et al, 2021 ), Parkinson's disease, and other dementias (Begemann et al, 2020 ; Hanoglu et al, 2021 ). TMS is a noninvasive approach that uses a magnetic field created outside the body to stimulate or inhibit specific areas of the brain by applying it to the scalp (Hamid et al, 2019 ).…”