Transcranial direct current stimulation for depression in a 92-year-old patient: a case study

Dear Editor, The prevalence of clinically significant depressive syndromes in people 60 years and older (i.e. late-life depression (LLD)) ranges from 9% to 18%, with incidence rates of 19.3 per 1000 person years. LLD has been linked to increased rates of suicide and premature mortality and more frequent use of health care with significantly higher health-care costs. There is considerable heterogeneity in the clinical presentation of major depression across the life cycle. Younger patients may have clinical profiles characterized by high trait anxiety and variable patterns of circadian, sleep, energy, and appetite disturbance. Those in midlife present the more stereotypic picture of anhedonia in combination with sleep disturbance, weight loss, and cognitive and motor impairments. In later life, clinical phenotypes are again more variable. This may well reflect different neuropathological pathways to illness and largely differentiate those with earlier onset who have grown older from those experiencing clinical depression for the first time. The prognosis of LLD is typically poor and is characterized by chronicity, mortality, and increased risk for cognitive impairment and progression to dementia. We aim to evaluate the clinical effects of using a transcranial direct current stimulation (tDCS) protocol – a non-invasive therapeutic strategy in terms of safety and clinical impact – on depressive symptoms. The rationale for using tDCS for depression is based on its properties of increasing (anodal) and decreasing (cathodal) cortical excitability. A larger study on depression and tDCS was recently published by Brunoni et al. The authors performed a controlled trial involving 120 patients with major depression. The results of this factorial study, in which subjects were randomized to receive active or sham tDCS and verum or placebo sertraline, showed a significant improvement in depressive symptoms for tDCS alone or combined with sertraline. Favourable results have also been found by other groups studying major depressive disorder. To the best of our knowledge, this has not yet been evaluated specifically for the old-old population. Mr J is a 92-year-old patient who has had major depression for the last 3 years. The patient presented no significant changes in complementary tests. Neuroimaging evaluation (magnetic resonance imaging) showed no volumetric or structural modifications other than age-related changes. At presentation, the patient was using escitalopram 10 mg/day without clinical response. Given the availability of tDCS device in our centre, it was decided the patient should undergo a tDCS protocol for major depression. The patient provided written informed consent in accordance with the requirements of Santa Casa Medical School’s institutional review board. Intervention protocol was as follows: 10 sessions with 2 mA for 30 min (only on weekdays). The anode was placed over the left dorsolateral prefrontal cortex (F3 according to the 10/20 electroencephalogram system) and the cathode was placed extracephalic at the contralateral deltoid. Depressive symptoms were assessed using the 17-item Hamilton Depression Rating Scale; we evaluated anxiety symptoms with bs_bs_banner