Thomas C. Neylan

Sleep disturbances are frequently observed in patients with neurodegenerative diseases, but in vivo evidence linking subcortical sleep–wake structures to sleep phenotypes is limited. We aim to examine associations between MRI-derived measures of subcortical sleep–wake regulating regions and polysomnographic sleep parameters in individuals with Alzheimer’s disease and cognitively healthy controls. Fifty-seven adults (45 with biomarker-confirmed Alzheimer’s disease and 12 cognitively healthy controls with normal pTau217 plasma levels) were recruited at the Hospital Clínic de Barcelona. All participants completed overnight polysomnography and 3T brain MRI, including a neuromelanin-sensitive sequence. MRI-derived measures of wake-promoting structures [locus coeruleus (LC), posterior hypothalamus and basal forebrain] and sleep-promoting regions (anterior hypothalamus) were obtained. We estimated the association between nocturnal polysomnographic variables [including total sleep time, sleep efficiency, time in rapid eye movement (REM) and non-REM sleep stages, REM sleep latency, wake after sleep onset and arousals] and MRI-derived measures. Then, a principal component analysis (PCA) was used to obtain derived patterns of sleep–wake regulation. Among sleep-promoting regions, higher anterior hypothalamic volumes correlated with greater time in bed (ρ = 0.19, P < 0.05), increased sleep period time (SPT) (ρ = 0.25, P < 0.01), and decreased REM over SPT (ρ = −0.22, P < 0.05). Within wake-promoting structures, higher posterior hypothalamic volume and LC integrity were associated with higher arousals (ρ = 0.32, P < 0.05 and ρ = 0.18, P < 0.05, respectively), and higher basal forebrain volume was associated with less REM over SPT (ρ = −0.25, P < 0.05). Control anatomic regions showed no associations with sleep parameters. The first two principal components of the PCA explain 47.7% of the variance. Anterior hypothalamic volumes clustered with longer, more efficient sleep, whereas LC integrity aligned with increased wakefulness and REM sleep latency. Alzheimer’s disease participants showed a shift towards the latter pattern, indicating disrupted sleep–wake regulation. MRI-derived measures of subcortical sleep–wake regions were associated with clinical sleep phenotypes in Alzheimer’s disease and ageing. These in vivo findings align with prior post-mortem research, reinforcing the role of subcortical structures in sleep disturbances and highlighting these circuits as potential targets to alleviate sleep symptoms and modify disease progression.

Objective: Polygenic risk scores (PRS) for posttraumatic stress disorder (PTSD) often account for a low amount of variance. Ancestry-related differences in PRS scale and variance limit cross-group comparisons. This methodological challenge further complicates gene-by-environment (GxE) analyses, given that socioenvironmental exposures are inequitably distributed across ethnoracial groups. We constructed an ancestry-calibrated polygenic risk score (AC-PRS) for PTSD in the largest longitudinal study of trauma survivors to date and investigated GxE interactions. Method: Recent trauma survivors (N=1,801) provided a blood specimen for genotyping. Six PTSD trajectories were previously identified from PTSD Checklist for DSM-5 (PCL-5) scores at 2-weeks, 8-weeks, 3-months, and 6-months post-trauma. Greenspace (normalized difference vegetation index [NDVI) and socioeconomic disadvantage (area deprivation index [ADI]) were derived from residential addresses. Logistic regressions examined interactions between newly developed AC-PRS and neighborhood factors on trajectories after adjusting for sociodemographic and trauma-related covariates. Secondary linear models considered GxE interactions on 6-month PCL-5 scores. Results: AC-PRS performed well across ethnoracial groups, explaining significant variability in PTSD trajectories (R ² =.053). ADI moderated the association between AC-PRS and the likelihood of assignment in a high nonremitting trajectory of PTSD symptoms and severity of symptoms at 6-months ( ps < .05). There were no NDVI x AC-PRS interactions in any models. Conclusions: AC-PRS captures genetic risk for PTSD in admixed trauma survivors, demonstrating good discrimination between nonremitting and resilient courses of PTSD. However, neighborhood disadvantage may modify utility of PRS for PTSD, warranting careful consideration when applying these scores across contexts.

Background: Adverse posttraumatic neuropsychiatric sequelae are common after trauma. Early identification of individuals at risk for these outcomes could enable the deployment of preventive interventions to survivors at greatest risk. Smartphone keystroke biomarkers show promise in identifying individuals with neuropsychiatric symptoms; however, to our knowledge, no research has examined whether they can be used to identify symptoms in the aftermath of trauma. Objective: This study evaluates whether passively collected keystroke data from smartphone use in daily life could identify individuals with high symptom levels, as well as worsening or recovery of symptoms, after trauma exposure. Methods: Data from a diverse cohort of individuals presenting to 27 emergency departments after trauma were analyzed. Inclusion criteria were presenting to the emergency department within 72 hours of trauma, age 18-75, and the ability to speak and read English. Exclusion criteria were solid organ injury, significant hemorrhage, operative intervention, or likely admission for over 72 hours. Participants installed an app that passively collected keystroke data during use of any app on their smartphone, beginning in the emergency department. Participants also completed serial symptom assessments over 8 weeks after trauma exposure. Results: A total of 3445 patients met study criteria, provided informed consent, and completed assessments in the emergency department. Of these, 1072 (mean age 40, SD 13; 616/1072, 57.46%, women; 565/1072, 52.71% non–Hispanic Black) installed the app on their Android smartphone and completed the 8-week assessment and were therefore included in analyses. Keystroke biomarkers related to typing speed, identified using bivariate linear mixed models controlling for false discovery rates, were associated with elevated pain, reexperiencing, and mental fatigue (absolute values of rs=0.22-0.25, Ps=.02). Separate change-of-operation and scrolling keystroke biomarkers were associated with increased reexperiencing symptoms (r=0.18, P=.047) and mental fatigue (rs=0.18-0.19, Ps=.031-.047). Further, changes in specific keystroke biomarkers were associated with worsening or recovery of pain (rs=0.07-0.10, Ps=.02), somatic symptoms (rs=0.02, Ps=.02), mental fatigue (rs=0.02-0.04, Ps=.02), sleep disturbance (absolute rs=0.07-0.09, Ps=.02), reexperiencing (rs=0.02-0.04, Ps=.02), and hyperarousal (rs=0.02-0.04, Ps=.02). Conclusions: In general, slower typing and scrolling speeds were associated with higher symptom levels, with small to medium effect sizes. Keystroke data passively collected via smartphone use may help identify individuals with significant or changing posttraumatic symptoms. Future research should continue to explore these keystroke biomarkers and whether they can be leveraged to connect vulnerable trauma survivors to appropriate services. Overall, these results add to the literature, indicating that passively collected keystroke data may help identify individuals with neuropsychiatric symptoms or changes and are, to our knowledge, the first to test whether keystroke biomarkers are useful in the aftermath of trauma. This represents a critical period during which preventive interventions could be deployed to reduce the long-term burden of trauma-related sequelae.

Residential segregation is associated with differential exposure to air pollution. Hippocampus structure and function are highly susceptible to pollutants and associated with posttraumatic stress disorder (PTSD) development. Therefore, we investigated associations between residential segregation, air pollutants, hippocampal neurobiology, and PTSD in recent trauma survivors. Participants (N = 278; 34% non-Hispanic white, 46% Non-Hispanic Black, 16% Hispanic) completed multimodal neuroimaging two weeks after trauma. Yearly averages of air pollutants (PM_2.5 and NO₂) and racial/economic segregation (Index of Concentration at the Extremes) were derived from each participant's address. Linear models assessed if air pollutants mediated associations between segregation and hippocampal volume, threat reactivity, or parahippocampal cingulum fractional anisotropy (FA) after covarying for age, sex, income, and 2-week PTSD symptoms. Further models evaluated if pollutants or segregation prospectively predicted PTSD symptoms six months post-trauma. We found that non-Hispanic Black participants lived in neighborhoods with significantly greater segregation and air pollution compared to Hispanic and non-Hispanic white participants (ps < 0.001). PM_2.5 concentration was positively correlated with threat reactivity (r(276) = 0.16, p < 0.006), while NO₂ concentration was positively correlated with hippocampus volume (r(276) = 0.17, p < 0.005) and negatively correlated with white matter tract FA (r(276) = -0.18, p < 0.003). There was a significant indirect effect of NO₂ between segregation and FA values (β = 0.08, 95% CI[0.01, 0.15]), and an indirect effect of PM_2.5 between segregation and threat reactivity (β = -0.08, 95% CI[-0.14, -0.01]). There was no direct effect of segregation on hippocampal features. Pollutants and segregation were not associated with PTSD symptoms. In conclusion, residential segregation is associated with greater air pollution exposure, which is in turn associated with variability in hippocampal features among recent trauma survivors. Further research is needed to assess relationships between other environmental factors and trauma and stress-related disorders.

Background: Systemic inflammation is hypothesized to contribute to post-traumatic stress disorder (PTSD) vulnerability. Few studies have examined inflammation shortly after trauma as a predictor of later PTSD symptoms. We examined whether inflammation from the emergency department (ED) post-trauma is associated with PTSD symptom severity over the following 6 months. Methods: Our sample included 742 AURORA participants, a longitudinal cohort of patients in 29 EDs across the United States after a traumatic stressor, followed up to 6 months. Plasma cytokines were assessed from a study blood draw in the ED: an inflammatory index (standardized sum of generally pro-inflammatory markers interleukin [IL]-6, IL-8, tumor necrosis factor alpha [TNF-α], interferon gamma [IFN-γ]), and generally anti-inflammatory IL-10. PTSD symptoms were self-reported at 2 weeks, 8 weeks, 3 months, and 6 months post-ED. Covariate-adjusted repeated-measures regressions estimated associations between inflammation and PTSD symptoms, overall and sex-stratified. Results: Among 742 participants (age m = 40.0 [13.7]; 479 [64.6%] female), PTSD symptoms were elevated then modestly decreased over follow-up. Higher ED inflammation was associated with higher PTSD symptoms across follow-up (standardized symptoms β = 0.05, 95% CI: 0.01–0.09), adjusted for potential confounders. Higher pro-inflammatory index levels and IL-6, IL-8, and TNF-α were associated with higher PTSD symptoms in males only, while higher IL-10 was associated with higher PTSD symptoms in females only. Conclusions: Pro-inflammatory levels shortly after traumatic stress are associated with heightened PTSD symptoms, particularly among males. Inflammatory markers may prove useful additions to prediction models for PTSD following trauma, with attention to sex differences.

Experiential avoidance is the unwillingness to come into contact with aversive internal experiences. Trauma exposure is associated with greater experiential avoidance and insomnia symptoms. Experiential avoidance may perpetuate insomnia symptoms in patients with posttraumatic stress disorder (PTSD). We examined the relationship between experiential avoidance and insomnia symptoms among veterans with PTSD (based on the Clinician-Administered PTSD Scale for DSM-5). The sample included 93 veterans (M = 54.7 years; 86.0% male) who attributed their sleep disturbance onset to experiences of trauma on the CAPS-5. Experiential avoidance, insomnia, sleep disturbance, daytime sleepiness, and daytime consequences were measured with the Brief Experiential Avoidance Questionnaire (BEAQ), Insomnia Severity Index (ISI), Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Scale (ESS), and International Classification of Sleep Disorders (ICSD) items. We conducted multiple linear regressions with age, sex, and BEAQ as the independent variables and sleep variables as the dependent variables. There were significant positive associations between the BEAQ and the ISI, PSQI daily disturbance factor, ESS, and ICSD daytime consequences. Greater experiential avoidance was associated with worse insomnia symptoms and consequences, particularly daytime dysfunction. Experiential avoidance may be an overlooked, but relevant treatment target for patients with comorbid insomnia and PTSD.

Background: Prior research identified profound sleep disruption in progressive supranuclear palsy (PSP). The hypothalamus and brainstem, areas that help regulate sleep/wake patterns, are among the earliest affected brain regions in PSP disease progression. Comparing polysomnography and quantitative-neuropathology metrics, we identified relative sparing of wake-promoting nuclei in PSP compared to Alzheimer’s disease, though PSP had more disrupted sleep. It led to the hypothesis that PSP patients have hyperinsomnia (or hyposomnia, little sleep) due to degeneration of sleep nuclei with a preservation of sleep neurons, causing a system unbalance. A higher neuronal count of wake-promoting nuclei was associated with greater nocturnal wake, regardless of disease. Specifically, orexinergic wake-promoting neurons in the lateral hypothalamus, previously described as the sleep-on/off switch, are relatively spared in PSP. Thus, we hypothesized that an orexinergic antagonist may be more effective in treating sleep/wake issues in PSP than other hypnotic medications. This study protocol was established to test the safety and efficacy of an orexinergic antagonist (suvorexant) targeting the wake-promoting system and contrasts it with a GABAergic receptor agonist (zolpidem) targeting sleep-promoting systems and placebo. Methods: This is a remote clinical trial, designed as a double-blind, cross-over, within-subject 6-week trial, with 3 one-week-long conditions, separated by 1-week washout periods. The order of the 3 regimens is randomized and counterbalanced: placebo (microcrystalline cellulose), 15 mg/day suvorexant, 5 mg/day zolpidem. Participants are recruited from doctor and study referrals, registries, and support groups. Once onboarded, the trial coordinator maintains communication with the participant/caregiver throughout the 6 weeks. Assessments include neurological interviews, cognitive testing, and subjective questionnaire packets. Sleep and circadian rhythms are assessed through ambulatory EEG and actigraphy monitoring devices worn by the participant throughout the trial. Discussion: The study design aims to reduce participant and caregiver burden, while improving accessibility to such a study. Administering a remote clinical trial for a rare disease, however, creates unique issues that would otherwise be absent from in-person studies. Particularly, a symptom rather than disease-modifying trial is challenging to recruit for when potential disease-modifying therapeutics are available. Needing to coordinate with non-associated medical offices to attain medical records or prescriptions can cause frustrations for the potential participant, medical office, and study team. In recruitment, onboarding, and trial maintenance, this study design relies on consistent communication to support participant enrollment and satisfaction. Trial registration: Treatment of Disturbed Sleep in Progressive Supranuclear Palsy (PSP); NCT04014389. Registered on June 2, 2019.

Tobacco smoking and drinking alcohol are common substance use behaviors influenced by both genetic risk and environmental exposures. Traumatic events are highly prevalent, affecting about 70% of people in their lifetime. After trauma, it is unclear what role post-traumatic stress disorder (PTSD) symptoms play in substance use behaviors when accounting for this genetic risk. We used data from the Advancing Understanding of RecOvery afteR traumA (AURORA), which included 2973 participants recruited at emergency departments (EDs) within 72 h of a traumatic event and followed over time. We measured PTSD symptoms via PTSD Checklist for the DSM-5. Tobacco and alcohol consumption as frequency, quantity, and quantity-frequency in the past 30 days. We generated polygenic risk scores with continuous shrinkage for cross-ancestry estimation (PRS-CSx). We tested for main effects between PRS-CSx scores and interactions with PTSD using quasipoisson regression, with week 8 PTSD symptoms and month 6 substance use behaviors after the traumatic event. Tobacco PRS-CSx score increased the risk of tobacco use by 14% (95% CI: 1.01, 1.29, p = 0.03), and alcohol PRS-CSx score did not demonstrate consistent associations in the whole cohort (IRR: 1.08, 95% CI: 0.97, 1.19, p = 0.16). When stratified by ancestry group, both tobacco (IRR: 1.36, 95% CI: 1.14, 1.61, p < 0.001) and alcohol (IRR: 1.24, 95% CI: 1.07, 1.44, p = 0.005) PRS-CSx scores were associated with their respective outcomes in the European ancestry subcohort. Participants with lower genetic risk had stronger associations between re-experiencing symptoms and tobacco use, while participants with higher genetic risk demonstrated weaker association between re-experiencing symptoms and tobacco use. A similar pattern was observed for negative alterations in cognition/mood (NACM) symptoms—participants with lower PRS-CSx scores had stronger associations between NACM symptoms with tobacco use, compared to participants with higher PRS-CSx scores. These interactions were both statistically significant, suggesting an antagonistic effect between PRS-CSx scores and PTSD symptoms on tobacco use.

Stress-related conditions disrupt cognition and emotion regulation and can result in psychiatric illness, but the neural circuit-level changes that can explain these broad effects remain unclear. To address this issue, we paired population-grounded discovery with out-of-sample testing. Using resting-state fMRI from > 14,000 healthy adults in the UK Biobank, we derived connectivity profiles tied to cognition (reaction time, numeric memory), and proxies of emotion dysregulation (neuroticism, anhedonia). We then applied the profiles to a trauma-exposed cohort (N = 306) to assess symptom relevance. Associations with stress, anxiety, and depression concentrated in a subset of circuit motifs, two of which recurred: (1) hyperintegration between the default mode and control/limbic interfaces, as well as (2) hypointegration between the default mode and visual interfaces, both tracked higher symptom burden. Static and dynamic analyses converged on the precuneus as a critical hub: stronger precuneus–visual coupling and greater occupancy of a precuneus-engaged dynamic state were related to lower symptoms, whereas the opposing state was related to higher burden. This novel hybrid approach—discover-then-project—thus yielded interpretable markers of circuit dysfunction that generalized to post-trauma psychopathology. Furthermore, the approach identified the precuneus as a potential target for mechanistically informed interventions.