Late-Life Depression: A Role for Accelerometer Technology in Diagnosis and Management

“Mr. G,” an 81-year-old Caucasian man with a history of mild neurocognitive disorder and unspecified bipolar or related disorder with atypical features (mood reactivity), was referred by his neurologist for a geriatric psychiatry assessment at the Senior Behavioral Health outpatient program at the University of California, San Diego. At the time of his initial presentation, the patient’s primary complaint was “my head feels as if it’s in a fog.” It was noteworthy that this patient was both affluent and very high functioning at baseline and ran a large business. He had concerns about his ability to function at work. The patient presented with a complicated medical history that included carotid stenosis with transient ischemic attacks (treated with stenting) and hypopharyngeal carcinoma, which required radiation treatment, which in turn caused mandibular osteonecrosis. This subsequently led to mandibular reconstruction surgery 2 years before his initial presentation. The patient also had right preauricular basal cell carcinoma (resected), low testosterone requiring supplementation, hypertension, and hypercholesterolemia. He had been diagnosed with severe carotid stenosis 1 year before presentation. He reported that he had experienced an episode of dizziness and transient unconsciousness (secondary to cerebral hypoxia), which led to the diagnosis of stenosis and emergent stenting of his carotid arteries. At initial presentation, Mr. G was taking aripiprazole at an atypical dosage of 2 mg once a week and fluoxetine at 20 mg/day for depression. He was also taking four additional medications at bedtime for insomnia: melatonin, 2.5 mg; temazepam, 15 mg; mirtazapine, 15 mg; and zaleplon, 10 mg. His nonpsychotropic medications included amlodipine, 5 mg/day; aspirin, 81 mg/day; levothyroxine, 150 mcg/day; lisinopril, 10 mg/day; lovastatin, 40 mg/day; tamsulosin, 0.4 mg at bedtime; and testosterone supplementation. The patient scored 20 out of a possible score of 30 on the Montreal Cognitive Assessment, which is consistent with mild neurocognitive disorder. A review of his performance on a previous administration of the assessment indicated that his score had dropped by 6 points over the past 14 months.

Mr. G’s prior psychiatric history was significant for a major depressive episode that began after he underwent the carotid stenting procedure 1 year before presentation. At the time, he was treated with fluoxetine at 40 mg/day and aripiprazole at 5 mg/day. However, this treatment precipitated what was described as a hypomanic episode, the defining features of which included impulsive business decisions, pressured speech, and insomnia. He was taken off fluoxetine and aripiprazole, and his hypomania resolved. Approximately 2 months before presentation, the patient demonstrated some amotivation and low energy, and he was restarted on fluoxetine at 20 mg/day by his primary care physician, but with minimal effect.

The patient’s physical examination revealed orthostatic hypotension, but his vital signs were otherwise within normal range. A comprehensive laboratory investigation, which included a complete blood count with differential analysis, a comprehensive metabolic panel, liver function tests, a cardiac workup, and assessment for hypothyroidism, hypogonadism, and low vitamin levels, was found to be noncontributory. A volumetric MRI of the brain demonstrated stable age-related volume loss and superimposed white matter changes suggesting chronic microvascular ischemia, but was otherwise found to be unremarkable. His hippocampal volume was found to be higher than the 5th percentile, and his lateral ventricular volume was at the 79th percentile, both within normal limits.

Mr. G was relatively nonspecific when describing his clinical complaints, using terms like “my brain is in a fog,” and he reported both hypersomnia and insomnia at different points in the initial assessment. His wife, who was present during the initial session as well as subsequent sessions, provided reliable collateral information, but stated that she was not always around him and not always observing him. He denied depressed mood, episodes of tearfulness, anhedonia, feelings of worthlessness, changes in appetite, thoughts of death, or fatigue. There was no initial reported history of psychomotor retardation.

We discussed referral for a formal sleep study (including polysomnography and multiple sleep latency tests), but polypharmacy was identified as a primary clinical issue initially, and we decided to defer this referral until after his sedative medications had been reduced. Initially, zaleplon and melatonin were discontinued. His mirtazapine dosage was then reduced to 7.5 mg at bedtime, but he reported recurrence of insomnia, and his nightly dose was increased back to 15 mg. Mr. G noted that he had been on temazepam for over 30 years and had relied on it for sleep. He became anxious at the notion of tapering off this medication, so this was deferred to a later time. Despite long-term use of temazepam, the reported confusion and “brain fog” were relatively recent complaints. In consultation with the patient’s primary care provider, Mr. G’s amlodipine was incrementally discontinued to address his hypotension, but this resulted in an exacerbation of hypertension, with his blood pressure reaching a high of 214/112 mmHg. Subsequently, amlodipine was restarted at 2.5 mg/day, which resulted in successful management of his hypertension without hypotension.

Assessment of Mr. G’s level of functioning suggested ongoing confusion and poor decision making over the course of the first month after resuming treatment with fluoxetine. This was the primary complaint of the patient and his wife, both of whom repeatedly said they were concerned about his ability to manage his business in his current mental state.

Because of unclear objective information about the patient’s sleep pattern, at this point, we recommended that the patient use a wrist-worn actigraph to record his daily movement as well as his sleep. Actigraphs are wearable devices designed to measure, map, and record the wearer’s motion. The primary sensor in an actigraph is an accelerometer, which measures changes in its own acceleration and thus can detect and map its own motion in three dimensions. Accelerometer technology is utilized in a broad range of industries (e.g., automobile, structural engineering, machinery development). Actigraphy, which relies on this technology, has become increasingly popular and accessible over the past 5 years, as wrist-worn devices have become more accurate and compact. The patient was receptive to the idea of actigraphy and purchased a device called “UP” (Jawbone, San Francisco). The patient received education on how to use the device to keep track of his daily step count and to record his movements during sleep, as well as to synchronize it with an app on his smartphone for visualization of data.

After monitoring for 1 week, it was noted at the next clinic visit that the patient had slept for an average of 8–9 hours of good quality sleep, ruling out insomnia. However, a review of his daytime motion data indicated that over the preceding 5 days, the patient had taken an average of only 836 steps per day (Figure 1). Moreover, this number was driven by a single day, when he had taken a long walk, at the insistence of his wife. With that day excluded, his average number of steps was 440 per day.

Further inquiry revealed that the patient lived in a very large house, and this step count was achieved simply by going from his bedroom to the bathroom or the dining room and back, and that the patient was spending the majority of his day lying in bed.

This newly identified severe psychomotor retardation, in combination with previously reported evidence of poor energy, low motivation, indecisiveness and confusion, and objective evidence of adequate sleep, led us to reconsider the treatment plan. We increased Mr. G’s dosage of fluoxetine to 40 mg/day and augmented this with aripiprazole at 2 mg/day. Over the course of the next 3 weeks, Mr. G demonstrated improvement in mood as well as energy, and his actigraphy data revealed that his average step count increased to approximately 4,000 steps per day. Moreover, when asked to provide information on his subjective experience using the device, Mr. G noted that he had found it helpful to keep track of his own movements and sleep and that being able to visualize the increase in his step count as his depression improved provided encouragement as well as positive reinforcement for remaining engaged in exercise. His wife supported this, reporting that the patient was meticulous about recording his step counts and that he had mentioned looking forward to sharing the data with his psychiatrist at his weekly follow-up visits.