Non-invasive, non-convulsive brain stimulation beyond TMS and ECT in late-life mental disorders: A systematic review

Abstract

Objective

This systematic review aims to present a comprehensive overview of research studies investigating non-invasive, non-convulsive neuromodulation techniques, beyond transcranial magnetic stimulation (TMS) and electroconvulsive therapy (ECT), for addressing late-life mental disorders typically occurring in outpatient settings in individuals aged 60 years and older.

Methods

A systematic literature search was performed on four databases yielding 5022 records: PubMed, EBSCO (APA PsycInfo, APA PsycArticles, Psychology and Behavioral Sciences Collection, PSYNDEX Literature with PSYNDEX Tests), Cochrane Library and Scopus.

Results

A total of 21 study records were included in this systematic review, comprising 6 study trials, of which only two were randomized controlled trials (RCTs), and 21 case reports extracted from the remaining 15 records. The predominant interventions investigated across the studies included transcranial direct current stimulation (tDCS), trigeminal nerve stimulation (TNS), and photobiomodulation (PBM). These interventions were primarily explored in the context of geriatric depression, but also in bipolar disorder, schizoaffective disorder, catatonic schizophrenia, and post-traumatic stress disorder (PTSD).

Limitations

The limited amount of data, biases in conducted studies and a lack of generalizability (e.g., many case reports) currently prevent quantitatively supported evaluations of the interventions in the older population.

Conclusions

Non-invasive, non-convulsive neuromodulation techniques for late-life mental disorders receive growing research interest. There is, however, a lack of adequately powered and well-designed high-quality studies for older age groups. Overall tDCS, TNS and PBM appeared to be safe and well-tolerated. Considering age-related challenges in pharmacological or psychotherapeutic interventions, non-invasive neuromodulation could be a promising treatment option.