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Sleep Memory Cues Do Not Boost Parkinson’s Motor Learning

Photoreal illustration of an older adult sleeping with overlay of memory and brain oscillation imagery, conveying sleep-based learning intervention.

Auditory targeted memory reactivation during a 2-hour nap did not improve motor retention in 20 Parkinson’s disease patients or 20 healthy older adults, even though the same cues changed sleep physiology by reducing spindle density and increasing slow-wave density.1 Research Highlights First Parkinson’s TMR test: Micca et al. studied 20 Parkinson’s disease patients and 20 …

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Dexamethasone Disrupts Mouse Sleep Through Orexin Hyperarousal

Photoreal illustration of a steroid pill bottle with overlay of disrupted sleep architecture, conveying glucocorticoid-induced insomnia mechanism.

A 2026 male-mouse study found that 30 mg/kg dexamethasone for 5 days increased light-phase wakefulness (t13 = 4.122, p = 0.0012), decreased NREM sleep (t13 = 4.412, p = 0.0007), and amplified orexin-neuron activity during NREM-to-wake transitions (F1,9 = 6.941, p = 0.0272). The result points to orexin-linked hyperarousal as a testable explanation for steroid-induced …

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EEG Alpha Density Decreased in Children, Increased in Adults

Photoreal illustration of children and adults with overlay of EEG brain rhythms, conveying developmental differences in sleep effects on brain activity.

A 2026 eNeuro analysis of 163 people ages 3.5–24.7 found that wake EEG amplitude behaved like a sleep-pressure marker, but wake alpha-density changed in opposite directions across development: it decreased overnight in children and increased overnight in adolescents and adults.1 Research Highlights Alpha density flipped by age: In 163 participants ages 3.5–24.7, oscillation density showed …

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Parkinson’s Disease Prevention: Prodromal Symptoms, RBD, Early Intervention Trials

Photoreal illustration of a brain with prodromal pathology and a clock indicating early-window intervention opportunity for Parkinson's prevention.

Parkinson’s disease has a years-to-decades prodromal stage where motor symptoms haven’t yet emerged but pathology is accumulating. A 2026 review by Schaeffer et al. synthesizes the case for (and limits of) intervening during this window — with implications for high-risk individuals weighing whether to enter preventive trials.1 Research Highlights Prodromal Parkinson’s disease is the period …

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Iceland Psychiatric Data: 21% Diagnosed, 34% on Psychotropics (2026)

MHD featured image for Iceland Psychiatric Health: 21% Diagnosed, 34% on Psychotropics.

Iceland is a registry-rich country with a small enough population that genuinely nationwide health data is feasible — not the survey-based approximations that anchor most psychiatric epidemiology elsewhere. A 2026 PLOS One study used the Iceland Screens, Treats, or Prevents Multiple Myeloma (iStopMM) cohort — 80,759 adults aged 40+, representing 54% of all eligible Icelanders …

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Lewy Body Dementia Cognitive Fluctuations Affect 75-90% of Patients

Photoreal illustration of fluctuating brain activity overlay on an older adult, conveying alertness variability characteristic of DLB.

Cognitive fluctuations are a defining feature of dementia with Lewy bodies (DLB), helping distinguish it from Alzheimer’s disease — but they remain notoriously difficult to characterize and measure. A 2026 review by Mahajan and colleagues maps the neurobiology, measurement, and clinical implications of fluctuations across the Lewy body spectrum.1 Research Highlights Cognitive fluctuations are episodes …

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