Discordant Biological and Chronological Age: Implications for Cognitive Decline and Frailty.

BACKGROUND: Older adults with discordant biological and chronological ages (BA and CA) may vary in cognitive and physical function from those with concordant BA and CA. METHODS: To make our approach clinically accessible, we created easy-to-interpret participant groups in the Health, Aging, and Body Composition Study (N = 2 458, 52% female participants, 65% White participants, age: 73.5 ±â€…2.8) based on medians of CA, and a previously validated BA index comprised of readily available clinical tests. Joint models estimated associations of BA-CA group with cognition (Modified Mini-Mental State Examination [3MS] and Digit Symbol Substitution Test [DSST]) and frailty over 10 years. RESULTS: The sample included the following: 32%, Young group (BA and CA < median); 21%, Prematurely Aging group (BA ≥ median, CA < median), 27%, Old group (BA and CA ≥ median), and 20%, Resilient group (BA < median, CA ≥ median). In education-adjusted models of cognition, among those with CA < median, the Prematurely Aging group performed worse than the Young at baseline (3MS and DSST p < .0001), but among those with CA ≥ median, the Resilient group did not outperform the Old group (3MS p = .31; DSST p = .25). For frailty, the Prematurely Aging group performed worse than the Young group at baseline (p = .0001), and the Resilient group outperformed the Old group (p = .003). For all outcomes, groups did not differ on change over time based on the same pairwise comparisons (p ≥ .40). CONCLUSIONS: Discordant BA and CA identify groups who have greater cognitive and physical functional decline or are more protected than their CA would suggest. This information can be used for risk stratification.

Considering hearing loss as a modifiable risk factor for dementia.

INTRODUCTION: Accumulating evidence links hearing loss to impaired cognitive performance and increased risk for dementia. Hearing loss can lead to deafferentation-induced atrophy of frontotemporal brain regions and dysregulation of cognitive control networks from increased listening effort. Hearing loss is also associated with reduced social engagement, loneliness, and depression, which are independently associated with poor cognitive function. AREAS COVERED: We summarize the evidence and postulated mechanisms linking hearing loss to dementia in older adults and synthesize the available literature demonstrating beneficial effects of hearing remediation on brain structure and function. EXPERT OPINION: : Further research is needed to evaluate whether treatment of hearing loss may reduce risk of cognitive decline and improve neural consequences of hearing loss. Studies may investigate the pathologic mechanisms linking these late-life disorders and identify individuals vulnerable to dementia, and future clinical trials may evaluate whether hearing treatment may reduce the risk for dementia.

Evidence suggests that hearing loss is associated with impaired cognitive performance, increased risk for dementia, and poor brain health in older adults. Fortunately, preliminary studies have shown positive effects of hearing treatment on cognitive outcomes and reversal of adverse neural effects of hearing loss. In the following, we review the available evidence providing support for hearing loss as a modifiable risk factor for dementia. However, there are important limitations to such findings, and further research is needed to definitively evaluate whether hearing treatment may protect cognitive and brain health in older adults. If future studies demonstrate that hearing treatment has beneficial effects on cognitive and neural outcomes, such results may take advantage of the recent widespread efforts to improve access to hearing treatment in the United States.

Proof of Concept of the Contribution of the Interaction between Trait-like and State-like Effects in Identifying Individual-Specific Mechanisms of Action in Biological Psychiatry.

Background: Identifying individual-specific mechanisms of action may facilitate progress toward precision medicine. Most studies seeking to identify mechanisms of action collapse together two distinct components: pre-treatment trait-like characteristics differentiating between individuals and state-like characteristics changing within each individual over the course of treatment. We suggest a conceptual framework highlighting the importance of studying interactions between trait-like and state-like components in the development of moderated mediation models that can guide personalized targeted interventions. Methods: To facilitate implementation of this framework, two empirical demonstrations are presented from a recent clinical trial and neuroimaging study. The first examines limbic reactivity during an emotional face task; the second concerns striatal activation in a monetary reward task. Results: In both tasks, considering the interaction between trait-like and state-like components predicted treatment outcome more robustly than did the trait-like or state-like components examined individually. Conclusions: These findings suggest that the extent to which state-like modulation of neural activations can serve as a potential treatment target depends on the pre-treatment, trait-like levels of activation in these regions. Thus, the interaction between trait-like and state-like components can serve as a promising path to the development of personalized interventions within a precision medicine framework in which mechanisms of action are individual-specific.

Structural brain features signaling trauma, PTSD, or resilience? A systematic exploration.

BACKGROUND: Studies have searched for neurobiological markers of trauma exposure, posttraumatic stress disorder (PTSD) diagnosis, and resilience to trauma to identify therapeutic targets for PTSD. Despite some promising results, findings are inconsistent. AIMS: The present study adopted a data-driven approach to systematically explore whether structural brain markers of trauma, PTSD, or resilience emerge when all are explored. MATERIALS & METHODS: Differences between clusters in the proportion of PTSD, healthy controls (HC), and trauma-exposed healthy controls (TEHC) served to indicate the presence of PTSD, trauma, and resilience markers, respectively. A total of 129 individuals, including 46 with PTSD, 49 TEHCs, and 34 HCs not exposed to trauma were scanned. Volumes, cortical thickness, and surface areas of interest were obtained from T1 structural MRI and used to identify data-driven clusters. RESULTS: Two clusters were identified, differing in the proportion of TEHCs but not of PTSDs or HCs. The cluster with the higher proportion of TEHCs, referred to as the resilience cluster, was characterized by higher volume in brain regions implicated in trauma exposure, especially the thalamus and rostral middle frontal gyrus. Cross-validation established the robustness and consistency of the identified clusters. DISCUSSION & CONCLUSION: Findings support the existence of structural brain markers of resilience.

A precision medicine tool to understand who responds best to hearing aids in late-life depression.

OBJECTIVES: Accumulating evidence suggests that hearing loss (HL) treatment may benefit depressive symptoms among older adults with Major Depressive Disorder (MDD), but the specific individual characteristics of those who stand to improve most are unknown. METHODS: N = 37 patients ≥60 years with HL and MDD received either active or sham hearing aids in this 12-week double-blind randomized controlled trial. A combined moderator approach was utilized in the analysis in order to examine multiple different pretreatment individual characteristics to determine the specific qualities that predicted the best depressive symptom response to hearing aids. Pretreatment characteristics included: Hearing Handicap Inventory for the Elderly (HHIE-S), pure tone average (PTA), speech reception threshold (SRT), Short Physical Performance Battery (SPPB), cognition (Repeatable Battery for the Assessment of Neuropsychological Status). RESULTS: The analysis revealed a combined moderator, predicting greater improvement with active versus sham hearing aids, that had a larger effect size than any individual moderator (combined effect size [ES] = 0.49 [95% CI: 0.36, 0.76]). Individuals with worse hearing-related disability (HHIE-S: individual ES = -0.16), speech recognition (SRT: individual ES = -0.14), physical performance (SPPB: individual ES = 0.41), and language functioning (individual ES = 0.19) but with relatively less severe audiometric thresholds (PTA: individual ES = 0.17) experienced greater depressive symptom improvement with active hearing aids. CONCLUSIONS: Older adults with relatively worse HL-related, physical, and cognitive functioning may stand to benefit most from hearing aids. Given the large number of older adults experiencing HL and MDD, a non-invasive and scalable means of targeting those most likely to respond to interventions would be valuable.

Blood-Based Biomarkers for Alzheimer's Disease in Older Adults with Posttraumatic Stress Disorder.

Background: Posttraumatic stress disorder (PTSD) is associated with cognitive decline and risk for dementia, but the neuropathology involved is unclear. Objective: The aim of this study was to determine whether PTSD is associated with increased levels of Alzheimer's disease (AD) blood-based biomarkers. Methods: Individuals aged 50 years and older with PTSD were compared to trauma-exposed healthy controls (TEHCs) at baseline on serum measures of amyloid-ß (Aß) 42 and 40 levels, the Aß 42/Aß 40 ratio, and total tau. Serum was analyzed using ultrasensitive Simoa Human Neurology 3-Plex A assay (N3PA). Linear regressions modeling each AD biomarker as a function of group were used to investigate between-group differences, controlling for age, sex, and educational attainment (years). Results: TEHC participants (N = 26) were 53.8% male with mean age 66.8±10.7, whereas PTSD participants (N = 44) were 47.7% male and aged 62.5±9.1 years. No between-group differences were noted on demographic characteristics or cognitive performance measured with the NIH Toolbox Cognition Battery. There were no significant between-group differences in serum Aß 40 (TEHC 105.8±51.6 versus PTSD 93.2±56.1, p = 0.46), Aß 42 (TEHC 8.1±4.6 versus PTSD 7.8±4.6, p = 0.63), Aß 42/Aß 40 (TEHC 0.08±0.03 versus PTSD 0.09±0.03, p = 0.27), or total tau (TEHC 0.5±0.3 versus PTSD 0.5±0.4, p = 0.77). Likewise, there were no significant interaction effects of amyloid or tau serum concentrations and PTSD group status on cognitive functioning. Conclusion: Findings from cognitive assessments and serum analyses do not support PTSD-induced neurodegeneration of the Alzheimer's type as a pathway linking PTSD to increased incidence of dementia in older adults.

Hearing Rehabilitative Treatment for Older Adults With Comorbid Hearing Loss and Depression: Effects on Depressive Symptoms and Executive Function.

OBJECTIVES: Recent research has revealed important neural and psychiatric consequences of hearing loss (HL) in older adults. This pilot study examined the neural effects of HL and the impact of hearing aids on neuropsychiatric outcomes in major depressive disorder (MDD). DESIGN: Twelve-week, double-blind, randomized controlled trial. PARTICIPANTS/INTERVENTION: N = 25 (≥60 years) with MDD and moderate-profound HL were randomized to receive hearing aids (100% gain targets) or sham hearing aids (flat 30 dB HL) in addition to psychiatric treatment-as-usual. MEASUREMENTS: Depressive symptoms (Hamilton Rating Scale for Depression [HRSD]), executive functioning (NIH Toolbox Flanker), integrity of auditory brain areas (structural MRI, diffusion tensor imaging). RESULTS: At baseline, worse speech discrimination was associated with auditory cortical thinning (Left anterior transverse temporal gyrus: r = 0.755, p = 0.012) and lower integrity of the superior longitudinal fasciculus (FA: Left r = 0.772, p = 0.025, Right r = 0.782, p = 0.022). After 12-weeks, hearing aids were effective at improving hearing functioning (Hearing Handicap for the Elderly: active -12.47 versus sham -4.19, t = -2.64, df = 18, p = 0.016) and immediate memory (active +14.9 versus sham +5.7, t = 2.28, df = 16, p = 0.037). Moderate improvement was observed for hearing aids on executive functioning but did not reach statistical significance (Flanker: active +4.8 versus sham -2.4, t = 1.95, df = 15, p = 0.071). No significant effect on depression was found (HRSD: active -5.50 versus sham -7.32, t = 0.75, df = 19, p = 0.46). CONCLUSIONS: HL can affect brain regions important for auditory and cognitive processing, and hearing remediation may have beneficial effects on executive functioning in MDD. Future studies may evaluate whether impairment in cognitive control consequent to HL may be an important risk mechanism for MDD.

Influences of dopaminergic system dysfunction on late-life depression.

Deficits in cognition, reward processing, and motor function are clinical features relevant to both aging and depression. Individuals with late-life depression often show impairment across these domains, all of which are moderated by the functioning of dopaminergic circuits. As dopaminergic function declines with normal aging and increased inflammatory burden, the role of dopamine may be particularly salient for late-life depression. We review the literature examining the role of dopamine in the pathogenesis of depression, as well as how dopamine function changes with aging and is influenced by inflammation. Applying a Research Domain Criteria (RDoC) Initiative perspective, we then review work examining how dopaminergic signaling affects these domains, specifically focusing on Cognitive, Positive Valence, and Sensorimotor Systems. We propose a unified model incorporating the effects of aging and low-grade inflammation on dopaminergic functioning, with a resulting negative effect on cognition, reward processing, and motor function. Interplay between these systems may influence development of a depressive phenotype, with an initial deficit in one domain reinforcing decline in others. This model extends RDoC concepts into late-life depression while also providing opportunities for novel and personalized interventions.

Frailty and Depression in Late Life: A High-Risk Comorbidity With Distinctive Clinical Presentation and Poor Antidepressant Response.

BACKGROUND: To investigate the longitudinal relationship between physical frailty, the clinical representation of accelerated biological aging, and antidepressant medication response in older adults with depressive illness. METHODS: An 8-week randomized placebo-controlled trial (escitalopram or duloxetine) followed by 10 months of open antidepressant medication treatment (augmentation, switch strategies) was conducted in an outpatient research clinic. 121 adults aged 60 years or older with major depressive disorder (MDD) or persistent depressive disorder and a 24-item Hamilton Rating Scale for Depression (HRSD) ≥16 were enrolled. Primary measures assessed serially over 12 months include response (50% reduction from baseline HRSD score), remission (HRSD score <10), and frailty (non/intermediate frail [0-2 deficits] vs frail [≥3 deficits]); latent class analysis was used to classify longitudinal frailty trajectories. RESULTS: A 2-class model best fit the data, identifying a consistently low frailty risk (63% of the sample) and consistently high frailty risk (37% of the sample) trajectory. Response and remission rates (ps ≤ .002) for adults in the high-risk frailty class were at least 21 percentage points worse than those in the low-risk class over 12 months. Furthermore, subsequent frailty was associated with previous frailty (ps ≤ .01) but not previous response or remission (ps ≥ .10). CONCLUSIONS: Antidepressant medication is poorly effective for MDD occurring in the context of frailty in older adults. Furthermore, even when an antidepressant response is achieved, this response does little to improve their frailty. These data suggest that standard psychiatric assessment of depressed older adults should include frailty measures and that novel therapeutic strategies to address comorbid frailty and depression are needed.

Who benefits most from expectancy effects? A combined neuroimaging and antidepressant trial in depressed older adults.

Depressed patients' expectations of improvement drive placebo effects in antidepressant clinical trials, yet there is considerable heterogeneity in the magnitude of expectancy effects. The present study seeks to identify those individuals who benefit most from expectancy effects using baseline neuroimaging and cognitive measures. Older adult outpatients diagnosed with major depressive disorder (MDD) participated in a prospective, 8-week clinical trial in which expectancy was experimentally manipulated and its effects on depression outcome measured. Based on the literature, we selected a priori 12 cognitive and brain-based variables linked to depression and expectancy, together with demographic variables, and incorporated them into a combined moderator. The combined moderator was developed as a weighted combination of the individual moderators, and was used to identify individuals who benefited most from expectancy effects. The combined moderator was found to predict differential change in depression severity scores between the high- vs. low-expectancy groups with a medium-size effect (Spearman effect size: 0.28). While at the sample level no expectancy effect was found, the combined moderator divided older adults with MDD into those who did and those who did not improve as the result of expectancy manipulation, with those benefiting from the manipulation showing greater processing speed, executive function, and frontostriatal white matter tract integrity. The findings suggest that it is possible to identify a subgroup of older adult individuals with MDD for whom expectancy manipulation results in greater antidepressant treatment response, supporting a precision medicine approach. This subgroup is characterized by distinct cognitive dysfunction and neuroimaging impairments profiles.

Cortical Thickness and Hippocampal Volume in Vascular and Non-vascular Depressed Patients.

Background: Reduced cortical thickness and hippocampal volume are prevalent markers of late life depression as well as mild cognitive impairment (MCI) but are conspicuously absent in the vascular depression (VD) literature. The present study aimed to determine differences in cortical thickness and hippocampal volume between VD and non-VD patients. Methods: Participants were enrolled in an 8-week open treatment antidepressant trial. Forty-one depressed individuals aged 50 and older underwent brain magnetic resonance imaging at baseline and were classified as VD or non-VD. Cortical thickness values for the left and right entorhinal, parahippocampal, and precuneal cortices, as well as left and right hippocampal volume, were linearly regressed on VD status to determine mean differences between VD and non-VD. Covariates included site, age, sex, and mean thickness or intracranial volume. Results: No statistical differences were found between VD and non-VD patients in cortical thickness of the bilateral precuneal, entorhinal, or parahippocampal cortices, or hippocampal volume (p > 0.001). Conclusions: The absence of statistical differences in gray matter between VD and non-VD patients raises several diagnostic, etiological, and developmental possibilities, namely that VD may not be connected with other late-life psychiatric illnesses such as MCI or dementia and that vascular disease may not be a common etiological risk factor for depression and dementia. Larger datasets, prospective longitudinal studies, and cognitively intact controls are needed to further address these types of questions.

Trajectories of Function and Symptom Change in Desvenlafaxine Clinical Trials: Toward Personalized Treatment for Depression.

PURPOSE/BACKGROUND: Heterogeneity has been documented in trajectories of symptom change during antidepressant treatment for major depressive disorder (MDD). It is unclear whether distinct trajectories of change exist for functioning during antidepressant treatment. METHODS/PROCEDURES: This analysis explored distinct trajectories of functioning in MDD and tested whether they corresponded to trajectories of symptom change. Data were from 4317 patients and were pooled from 9 randomized placebo-controlled trials. Growth mixture modeling was used to identify trajectories of Hamilton Rating Scale for Depression (HRSD) and Sheehan Disability Scale (SDS) for placebo- and desvenlafaxine-treated patients. FINDINGS/RESULTS: Three trajectories were identified for symptoms (HRSD) in patients receiving placebo (mean reduction baseline to week 8, -18.4 [most favorable] to -2.6 points [least favorable]). Four HRSD trajectories were identified for patients receiving desvenlafaxine (mean reduction from baseline to week 8, -17.2 [most favorable] to -2.6 points [least favorable]). Four trajectories were identified for functioning (SDS) in patients receiving placebo (mean reduction baseline to week 8, -13.6 [most favorable] to -0.8 points [least favorable]), and 3 for desvenlafaxine (-12.8 to -1.4 points, respectively). Percentages of agreement between most favorable HRSD and SDS trajectories were 75% (placebo) and 85% (desvenlafaxine), and for least favorable trajectories were 88% (placebo) and 80% (desvenlafaxine). IMPLICATIONS/CONCLUSIONS: Distinct trajectories of change based on symptoms and functioning were identified among patients with MDD receiving desvenlafaxine and among patients with MDD receiving placebo. Differentiating subpopulations of patients has the potential to provide a more personalized treatment of patients with MDD.ClinicalTrials.govIdentifiers: NCT00072774; NCT00277823; NCT00300378; NCT00384033; NCT00798707; NCT00863798; NCT01121484; NCT00824291; NCT01432457.

Right parahippocampal volume deficit in an older population with posttraumatic stress disorder.

BACKGROUND: Posttraumatic Stress Disorder (PTSD) is an increasingly prevalent condition among older adults and may escalate further as the general population including veterans from recent conflicts grow older. Despite growing evidence of higher medical comorbidity, cognitive impairment and dementia, and disability in older individuals with PTSD, there are very few studies examining brain cortical structure in this population. Hence, we examined cortical volumes in a cross-sectional study of veterans and civilians aged ≥50 years, of both sexes and exposed to trauma (interpersonal, combat, non-interpersonal). METHODS: Cortical volumes were obtained from T1-weighted structural MRI and compared between individuals with PTSD and Trauma Exposed Healthy Controls (TEHC) adjusting for age, sex, estimated intracranial volume, depression severity, and time elapsed since trauma exposure. RESULTS: The PTSD group (N = 55) had smaller right parahippocampal gyrus compared to TEHC (N = 36), corrected p(pFWER) = 0.034, with an effect size of 0.75 (Cohen's d), with no significant group differences in other cortical areas. CONCLUSIONS: These findings are different from the structural brain findings reported in studies in younger age groups (larger parahippocampal volume in PTSD patients), suggesting a possible significant change in brain structure as PTSD patients age. These results need replication in longitudinal studies across the age-span to test whether they are neuroanatomical markers representing disease vulnerability, trauma resilience or pathological neurodegeneration associated with cognitive impairment and dementia.

Association of White Matter Integrity With Executive Function and Antidepressant Treatment Outcome in Patients With Late-Life Depression.

OBJECTIVE: While patients with late-life depression (LLD) often exhibit microstructural white matter alterations that can be identified with diffusion tensor imaging (DTI), there is a dearth of information concerning the links between DTI findings and specific cognitive performance, as well as between DTI measures and antidepressant treatment outcomes. DESIGN: Neuroimaging and cognitive tests were conducted at baseline in 71 older adults participating in a larger, 8-week duration antidepressant randomized controlled trial. Correlations between DTI measures of white matter integrity evaluated with tract-based spatial statistics, baseline neurocognitive performance, and prospective antidepressant treatment outcome were evaluated. RESULTS: Fractional anisotropy (FA), an index of white matter integrity, was significantly positively associated with better cognitive function as measured by the Initiation/Perseveration subscale of the Dementia Rating Scale in the bilateral superior longitudinal fasciculus (SLF), bilateral SLF-temporal, and right corticospinal tract (CST). An exploratory analysis limited to these tracts revealed that increased FA in the right CST, right SLF, and right SLF-temporal tracts was correlated with a greater decrease in depressive symptoms. Increased FA in the right CST predicted a greater chance of remission, while increased FA in the right CST and the right SLF predicted a greater chance of treatment response. CONCLUSION: In late-life depression LLD subjects, white matter integrity was positively associated with executive function in white matter tracts which act as key connecting structures underlying the cognitive control network. These tracts may play a role as a positive prognostic factor in antidepressant treatment outcome.

Age-Related Hearing Loss, Neuropsychological Performance, and Incident Dementia in Older Adults.

BACKGROUND: Age-related hearing loss (HL) has been associated with dementia, though the neurocognitive profile of individuals with HL is poorly understood. OBJECTIVE: To characterize the neurocognitive profile of HL. METHODS: N = 8,529 participants from the National Alzheimer's Coordinating Center ≥60 years and free of cognitive impairment who were characterized as Untreated-, Treated-, or No HL. Outcomes included executive function (Trail Making Test [TMT] Part B), episodic memory (Immediate/Delayed Recall), language fluency (Vegetables, Boston Naming Test), and conversion to dementia. Regression models were fit to examine associations between HL and neurocognitive performance at baseline. Cox proportional hazards models examined the links between HL, neurocognitive scores, and development of dementia over follow-up. RESULTS: At baseline, those with Untreated HL (versus No HL) had worse neurocognitive performance per standardized difference on executive function (TMT Part B [mean difference = 0.05 (95% CI 0.00, 0.10)]) and language fluency (Vegetables [mean difference = -0.07 (95% CI -0.14, -0.01)], Boston Naming Test [mean difference = -0.07 (95% CI -0.13, -0.01)]). No differences in these neurocognitive performance scores were demonstrated between Treated HL and No HL groups other than MMSE [mean difference = -0.06 (95% CI -0.12, 0.00)]. Through follow-up, executive dysfunction differed by hearing group (χ2(2) = 46.08, p < 0.0001) and was present among 39.12% in No HL, 44.85% in Untreated HL, and 49.40% in Treated HL. Worse performance across all cognitive domains predicted incident dementia. CONCLUSION: The observed association between Untreated HL and lower cognitive ability that improved when hearing aids were worn may reflect an inability to hear the test instructions. Future studies using cognitive assessments validated for use in HL are needed to evaluate the neuropsychological profile of HL and identify individuals at risk for dementia.