Repetitive transcranial magnetic stimulation for treatment of medication-resistant depression in older adults: a case series

Transcranial magnetic stimulation (TMS) for geriatric depression

BACKGROUND

The prevalence of treatment-resistant geriatric depression (GD) highlights the need for treatments that preserve cognitive functions and recognize polypharmacy in elderly, yet effectively reduce symptom burden. Transcranial magnetic stimulation (TMS) is a proven intervention for treatment-resistant depression in younger adults but the efficacy of TMS to treat depressed older adults is still unclear. This review provides an updated view on the efficacy of TMS treatment for GD, discusses methodological differences between trials in TMS application, and explores avenues for optimization of TMS treatment in the context of the ageing brain.

METHODS

A systematic review was conducted to identify published literature on the antidepressant efficacy of TMS for GD. Databases PubMed, Embase, and PsycINFO were searched for English language articles in peer-reviewed journals in March 2021.

RESULTS

Seven randomized controlled trials (RCTs) (total n = 260, active n = 148, control n = 112) and seven uncontrolled trials (total n = 160) were included. Overall, we found substantial variability in the clinical response, ranging from 6.7% to 54.3%.

CONCLUSIONS

The reviewed literature highlights large heterogeneity among studies both in terms of the employed TMS dosage and the observed clinical efficacy. This highlights the need for optimizing TMS dosage by recognizing the unique clinical features of GD. We showcase a set of novel approaches for the optimization of the TMS protocol for depression and discuss the possibility for a standardized TMS protocol tailored for the treatment of GD.

Adverse events of repetitive transcranial magnetic stimulation in older adults with depression, a systematic review of the literature

OBJECTIVE

In the last decade, repetitive transcranial magnetic stimulation (rTMS) has been introduced as a non-invasive neuromodulation therapy for depression. Little is known, however, about (serious) adverse events (AE) of rTMS in older adults with a depression. In this article, we want to study what is known about (serious) AE of rTMS in older adults (>60 years) with late-life depression (LLD).

METHODS

A systematic search has been performed according to the PRISMA guidelines in PubMed, EMBase and PsycInfo. We have screened 622 articles for eligibility. Eleven studies, evaluating 353 patients in total, were included in this review.

RESULTS

AE were reported in 12.4% of the older adults with a LLD treated with rTMS, serious AE in 1.5%. Headache (6.9%) and discomfort at the stimulation site (2.7%) are the most commonly reported AE. Serious AE reported are: psychiatric hospitalization (three times), a combination of posterior vitreous detachment and retinal tear, and increased suicide ideation (both once).

CONCLUSIONS

rTMS in older adults with LLD was concluded overall to be safe due to the low frequency of AE reported in trials and observational studies. In case-reports, however, more serious AE have been described. To tailor use of rTMS in older adults with LLD, more research is needed in larger samples to optimize tolerance.

Anodal Direct Current Stimulation of the Cerebellum Reduces Cerebellar Brain Inhibition but Does Not Influence Afferent Input from the Hand or Face in Healthy Adults

BACKGROUND

The cerebellum controls descending motor commands by outputs to primary motor cortex (M1) and the brainstem in response to sensory feedback. The cerebellum may also modulate afferent input en route to M1 and the brainstem.

OBJECTIVE

The objective of this study is to determine if anodal transcranial direct current stimulation (tDCS) to the cerebellum influences cerebellar brain inhibition (CBI), short afferent inhibition (SAI) and trigeminal reflexes (TRs) in healthy adults.

METHODS

Data from two studies evaluating effects of cerebellar anodal and sham tDCS are presented. The first study used a twin coil transcranial magnetic stimulation (TMS) protocol to investigate CBI and combined TMS and cutaneous stimulation of the digit to assess SAI. The second study evaluated effects on trigemino-cervical and trigemino-masseter reflexes using peripheral nerve stimulation of the face.

RESULTS

Fourteen right-handed healthy adults participated in experiment 1. CBI was observed at baseline and was reduced by anodal cerebellar DCS only (P < 0.01). There was SAI at interstimulus intervals of 25 and 30 ms at baseline (both P < 0.0001), but cerebellar tDCS had no effect. Thirteen right-handed healthy adults participated in experiment 2. Inhibitory reflexes were evoked in the ipsilateral masseter and sternocleidomastoid muscles. There was no effect of cerebellar DCS on either reflex.

CONCLUSIONS

Anodal DCS reduced CBI but did not change SAI or TRs in healthy adults. These results require confirmation in individuals with neurological impairment.

Systematic Review of Cognitive Effects of Electroconvulsive Therapy in Late-Life Depression

OBJECTIVE

Late-life depression (LLD) is known to negatively impact cognition even after remission of mood symptoms. Electroconvulsive therapy (ECT) and newer nonconvulsive electrical and magnetic brain stimulation interventions have been shown to have cognitive effects in patients with neuropsychiatric disorders.

METHODS

This review systematically assessed the effects of ECT on cognition in LLD. EMBASE, Ovid Medline, and PsycINFO were systematically searched through June 2015. The search was limited to publications from peer-reviewed journals in the English language.

RESULTS

A total of 5,154 publications was identified; 318 were reviewed in full text, of which 39 publications related to ECT were included. We focused this review only on ECT because evidence on newer interventions was deemed insufficient for a systematic review. This literature suggests increased rates of interictal and postictal cognitive decline with ECT but no long-term (i.e., 6 months or longer) deleterious effects on cognition. Instead, long-term cognitive outcomes with ECT have been reported as either not changed or improved. This literature favors nondominant unilateral ECT over bilateral ECT for cognition.

CONCLUSION

Published literature on brain stimulation interventions in LLD is mainly limited to ECT. This literature suggests that deleterious effects of ECT in LLD are limited and transient, with better cognitive outcomes with unilateral ECT. There is not enough evidence to fully characterize long-term deleterious effects of ECT or effects of newer brain stimulation techniques on cognition in LLD.

Neuromodulation therapies for geriatric depression

Depression is frequent in old age and its prognosis is poorer than in younger populations. The use of pharmacological treatments in geriatric depression is limited by specific pharmacodynamic age-related factors that can diminish tolerability and increase the risk of drug interactions. The possibility of modulating cerebral activity using brain stimulation techniques could result in treating geriatric depression more effectively while reducing systemic side effects and medication interactions. This may subsequently improve treatment adherence and overall prognosis in the older patient. Among clinically available neuromodulatory techniques, electroconvulsive therapy (ECT) remains the gold standard for the treatment of severe depression in the elderly. Studies have proven that ECT is more effective and has a faster onset of action than antidepressants in the treatment of severe, unipolar, geriatric depression and that older age is a predictor of rapid ECT response and remission. The application of novel and more tolerable forms of ECT for geriatric depression is currently being examined. Preliminary results suggest that right unilateral ultrabrief ECT (RUL-UB ECT) is a promising intervention, with similar efficacy to brief-pulse ECT and fewer adverse cognitive effects. Overall findings in repetitive transcranial magnetic stimulation (rTMS) suggest that it is a safe intervention in geriatric depression. Higher rTMS stimulation intensity and more treatments may need to be given in the elderly to achieve optimal results. There is no specific data on vagus nerve stimulation in the elderly. Transcranial direct current stimulation, magnetic seizure therapy and deep brain stimulation are currently experimental, and more data from geriatric samples is needed.

Transcranial magnetic stimulation for geriatric depression: Promises and pitfalls

As the global population gets older, depression in the elderly is emerging as an important health issue. A major challenge in treating geriatric depression is the lack of robust efficacy for many treatments that are of significant benefit to depressed working age adults. Repetitive transcranial magnetic stimulation (rTMS) is a novel physical treatment approach used mostly in working age adults with depression. Many TMS trials and clinics continue to exclude the elderly from treatment citing lack of evidence in this age group. In this review, we appraise the evidence regarding the safety and efficacy of rTMS in the elderly. A consistent observation supporting a high degree of tolerability and safety among the elderly patients emerged across the Randomised Controlled Trials and the uncontrolled trials. Further, there is no reliable evidence negating the utility of rTMS in the elderly with depression. We also identified several factors other than age that moderate the observed variations in the efficacy of rTMS in the elderly. These factors include but not limited to: (1) brain atrophy; (2) intensity and number of pulses (dose-response relationship); and (3) clinical profile of patients. On the basis of the current evidence, the practice of excluding elderly patients from TMS clinics and trials cannot be supported.

Applications of transcranial magnetic stimulation and magnetic seizure therapy in the study and treatment of disorders related to cerebral aging

Transcranial magnetic stimulation (TMS) can be used to probe cortical function and treat neuropsychiatric illnesses. TMS has demonstrated neuroplastic effects akin to long-term potentiation and long-term depression, and therapeutic applications are in development for post-stroke recovery, Alzheimer's disease, and depression in seniors. Here, we discuss two new directions of TMS research relevant to cerebral aging and cognition. First, we introduce a paradigm for enhancing cognitive reserve, based on our research in sleep deprivation. Second, we discuss the use of magnetic seizure therapy (MST) to spare cognitive functions relative to conventional electroconvulsive therapy, and as a means of providing a more potent antidepressant treatment when subconvulsive TMS has shown modest efficacy in seniors. Whether in the enhancement of cognition as a treatment goal, or in the reduction of amnesia as a side effect, these approaches to the use of TMS and MST merit further exploration regarding their clinical potential.

rTMS for pharmacoresistant major depression in the clinical setting of a psychiatric hospital: effectiveness and effects of age

BACKGROUND

Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive method of brain stimulation used in the treatment of drug-resistant major depressive disorder (MDD). It has been suggested that the efficacy of rTMS decreases with the age of the patient, but the data are contradictory. Here, we analyze in our clinical setting the efficacy of a 3-week rTMS treatment in drug-resistant MDD during a 3 month period and the potential influence of age on this efficacy.

METHODS

Stimulation consisted of 15 sessions of rTMS over the dorsolateral prefrontal cortex. Clinical evaluations included the Hamilton Depression Rating Scale (HDRS), and the Beck Depression Inventory (BDI) at baseline, after 3 weeks of treatment, and 1 month and 3 months after the last session.

RESULTS

Data from 93 patients issued from the 178 patients active file were analyzed. The antidepressant effect observed in the two age groups (<65 and ≥65) did not differ at the end of the treatment and 3 months later, with a comparable number of responders (50% decrease in HDRS score from baseline) (53.3% for age <65 versus 46.7% for age ≥65, p=0.51). The treatment had a significant effect over time. We found no evidence of the age affecting outcome at 3 months after the last session.

LIMITATIONS

Previous antidepressant treatments, and therapeutic drug use modifications after rTMS treatment, degree of pharmaco-resistance or duration of current episode are not reported.

CONCLUSION

RTMS of the DFPLC is effective as an add-on treatment for cases of pharmacologically refractory major depression, independent of the patient age.

Neuromodulation for treatment-resistant depression

Treatment-resistant depression affects at least 1-3% of the US population. This article reviews the current state of focal neuromodulation therapies for treatment-resistant depression, focusing on those treatments published clinical data. These include transcranial magnetic stimulation, transcranial direct current stimulation, magnetic seizure therapy, vagus nerve stimulation, direct cortical stimulation, and deep brain stimulation among others. Of these, only two (transcranial magnetic stimulation and vagus nerve stimulation) currently have US Food and Drug Administration approval for the treatment of depression.

Canadian Network for Mood and Anxiety Treatments (CANMAT) Clinical guidelines for the management of major depressive disorder in adults. IV. Neurostimulation therapies

BACKGROUND

In 2001, the Canadian Psychiatric Association and the Canadian Network for Mood and Anxiety Treatments (CANMAT) partnered to produce evidence-based clinical guidelines for the treatment of depressive disorders. A revision of these guidelines was undertaken by CANMAT in 2008-2009 to reflect advances in the field. There is renewed interest in refined approaches to brain stimulation, particularly for treatment resistant major depressive disorder (MDD).

METHODS

The CANMAT guidelines are based on a question-answer format to enhance accessibility to clinicians. An evidence-based format was used with updated systematic reviews of the literature and recommendations were graded according to Level of Evidence using pre-defined criteria. Lines of Treatment were identified based on criteria that included evidence and expert clinical support. This section on "Neurostimulation Therapies" is one of 5 guidelines articles.

RESULTS

Among the four forms of neurostimulation reviewed in this section, electroconvulsive therapy (ECT) has the most extensive evidence, spanning seven decades. Repetitive transcranial magnetic (rTMS) and vagus nerve stimulation (VNS) have been approved to treat depressed adults in both Canada and the United States with a much smaller evidence base. There is also emerging evidence that deep brain stimulation (DBS) is effective for otherwise treatment resistant depression, but this is an investigational approach in 2009.

LIMITATIONS

Compared to other modalities for the treatment of MDD, the data based is limited by the relatively small numbers of randomized controlled trials (RCTs) and small sample sizes.

CONCLUSIONS

There is most evidence to support ECT as a first-line treatment under specific circumstances and rTMS as a second-line treatment. Evidence to support VNS is less robust and DBS remains an investigational treatment.

Emerging targets for antidepressant therapies

Despite adequate antidepressant monotherapy, the majority of depressed patients do not achieve remission. Even optimal and aggressive therapy leads to a substantial number of patients who show minimal and often only transient improvement. In order to address this substantial problem of treatment-resistant depression, a number of novel targets for antidepressant therapy have emerged as a consequence of major advances in the neurobiology of depression. Three major approaches to uncover novel therapeutic interventions are: first, optimizing the modulation of monoaminergic neurotransmission; second, developing medications that act upon neurotransmitter systems other than monoaminergic circuits; and third, using focal brain stimulation to directly modulate neuronal activity. We review the most recent data on novel therapeutic compounds and their antidepressant potential. These include triple monoamine reuptake inhibitors, atypical antipsychotic augmentation, and dopamine receptor agonists. Compounds affecting extra-monoamine neurotransmitter systems include CRF(1) receptor antagonists, glucocorticoid receptor antagonists, substance P receptor antagonists, NMDA receptor antagonists, nemifitide, omega-3 fatty acids, and melatonin receptor agonists. Focal brain stimulation therapies include vagus nerve stimulation (VNS), transcranial magnetic stimulation (TMS), magnetic seizure therapy (MST), transcranial direct current stimulation (tDCS), and deep brain stimulation (DBS).