Neuropsychologic effects of neuromodulation techniques for treatment-resistant depression: A review

Abstract

Electroconvulsive therapy (ECT) and ablative neurosurgical procedures are established interventions for treatment-resistant depression (TRD), but their use may be limited in part by neuropsychological adverse effects. Additional neuromodulation strategies are being developed that aim to match or exceed the efficacy of ECT/ablative surgery with a better neurocognitive side effect profile. In this review, we briefly discuss the neurocognitive effects of ECT and ablative neurosurgical procedures, then synthesize the available neurocognitive information for emerging neuromodulation therapies including repetitive transcranial magnetic stimulation, magnetic seizure therapy, transcranial direct current stimulation, vagus nerve stimulation, and deep brain stimulation. The available evidence suggests these procedures may be more cognitively benign relative to ECT or ablative neurosurgical procedures, though further research is clearly needed to fully evaluate the neurocognitive effects, both positive and negative, of these novel neuromodulation interventions.

Neuromodulation for treatment-refractory major depressive disorder

“…23 Factors associated with greater cognitive impairment following electroconvulsive therapy include pre-existing cognitive impairment, older age and the use of bilateral electroconvulsive therapy. 24 There are no absolute contraindications to electroconvulsive therapy, and it can be used safely during pregnancy.…”

“…Most studies have found no immediate or prolonged negative effects of transcranial magnetic stimulation on cognition. 38 A study involving 30 patients with major depressive disorder found that, one week after finishing the course of treatment, cognitive performance remained constant or improved (v. pretreatment) among patients who received transcranial magnetic stimulation to the left dorsolateral prefrontal cortex, while deficits in anterograde memory were observed among patients who underwent right unilateral electroconvulsive therapy. 39 Transcranial magnetic stimulation may produce transient headache or local pain in 30%-40% of patients.…”

Regenerative Medicine for Neurological Diseases with the Use of Electrical Stimulation

“…In fact, electrical convulsive seizure is clinically performed for severe depression and this therapy showed increase of the proliferation and neuronal differnetiation of hippocampal precursors in a depression model of animals [30][31][32]. For Alzheimer's disease, a previous report showed that transcranial direct current stimulation enhanced aspects of memory performance in both healthy controls and individuals with Alzheimer's disease [33]. However, an operation for electrode insertion is needed, and this is invasive for patients.…”

The Use of ECT and MST in treating depression

“…Whilst there are studies which have not found adverse effects on cognitive function (Sienaert et al, 2010a), for patients where minimizing retrograde amnesia is a priority, right unilateral electrode placement should be the preferred initial choice, given the accumulated evidence suggesting fewer cognitive side effects (Kellner et al, 2010a;O ' Connor et al, 2010a). Some patient-specifi c factors increase the likelihood of cognitive side effects: increasing age, lower education level, lower pre-morbid IQ and psychotropic medication (Moreines et al, 2011). Where there are concerns about cognition, use of dose titration to determine the minimum effective dose and limiting number and frequency of sessions can help to reduce the frequency and intensity of cognitive side effects.…”

“…The neuropsychological effects of MST have recently been reviewed (Moreines et al, 2011). Though studies in humans are based on individual case reports or small (less than 20 participants) groups there is growing evidence that MST is associated with few subjective and objective cognitive side effects (Hoy & Fitzgerald, 2010b;Kayser et al, 2011;Kosel et al, 2003;Lisanby et al, 2003a;Lisanby et al, 2001b), as well as rapid recovery of orientation after treatment compared with ECT (Kirov et al, 2008;White et al, 2006).…”