Shahab Haghayegh

• PhD
• Instructor at Harvard Medical School

Introduction Ambulatory blood pressure (BP) monitoring encapsulates 24-h BP patterns across the sleep-wake cycle and provides a comprehensive assessment of BP regulation with certain features, such as sleep-time dipping, that can better predict health outcomes than traditional office BP measurements. However, 24-h BP patterns remain understudied in...

Background Cardiovascular diseases are closely linked to cognitive health. Subclinical cardiovascular functional changes, such as cardiac autonomic dysfunction, precede cardiovascular diseases and improve risk stratification. Continuous monitoring of heart rate or pulse rate is a commonly used approach to evaluate cardiac cycle and autonomic regula...

Growing evidence suggests that abnormal diurnal blood pressure rhythms may be associated with many adverse health outcomes, including increased risk of cognitive impairment and dementia. This study evaluates methodological aspects of research on bidirectional associations between ambulatory blood pressure monitoring (ABPM) patterns and cognitive fu...

Background Early identification of individuals at risk for cognitive impairment is crucial, as the preclinical phase offers an opportunity for interventions to slow disease progression and improve outcomes. Objective While sleep electroencephalography (EEG) has shown significant promise in detecting cognitive impairment, this study aims to 1) deve...

The autonomic nervous system (ANS) regulates physiological changes during pregnancy, supporting fetal development and homeostasis. Heart rate (HR) and heart rate variability (HRV) are non-invasive ANS biomarkers; however, their circadian rhythms during pregnancy remain underexplored due to the lack of continuous data collection, a gap now addressed...

Background Previous studies have linked disrupted circadian rest‐activity rhythms (RARs) with increased risks for Alzheimer’s disease and related dementias. However, these findings may be confounded due to the observational nature and offer limited insights into causality. We aimed to employ target trial emulation to estimate potential causal effec...

Growing evidence suggests that abnormal diurnal blood pressure rhythms may be associated with many adverse health outcomes including increased risk of cognitive impairment and dementia. This study evaluates methodological aspects of research on bidirectional associations between ambulatory blood pressure monitoring (ABPM) patterns and cognitive fun...

Background The relationship between 24-hour rest-activity rhythms (RARs) and risk for dementia or mild cognitive impairment (MCI) remains an area of growing interest. Previous studies were often limited by small sample sizes, short follow-ups, and older participants. More studies are required to fully explore the link between disrupted RARs and dem...

Introduction Prior studies of older adults have demonstrated that the development and progression of Alzheimer’s disease are tightly linked with longer daytime naps in a potentially bidirectional manner. It remains unclear whether daytime sleep behaviors in middle-to-older aged adults are linked to the risk for dementia. Methods We studied 85,037...

Introduction While the inter-relationship between parkinsonism and Parkinson’s disease (PD) in older adults remains unclear, both phenotypes are related to PD pathology. Adults with PD commonly exhibit nonmotor symptoms such as disturbances in sleep-wake cycles or rest-activity rhythm (RAR). In a previous study of older men, RAR disturbances preced...

Introduction Delirium is a sudden, transient, but reversible neurological condition as a result of acute stressors, such as hospitalization for surgery or acute illness, and predisposed by many underlying conditions, including age, cognitive decline, and multiple comorbidities. We recently showed that self-reported sleep disturbances prior to surge...

Introduction Physiological outputs such as motor activity display complex fluctuations with a delicate pattern balanced between randomness and excessive regularity. Altered fractal patterns were observed in patients with Parkinson’s disease (PD). We examined whether perturbed motor activity fluctuation patterns are associated with the risk of devel...

Unlabelled: Over the past few years, artificial intelligence (AI) has emerged as a powerful tool used to efficiently automate several tasks across multiple domains. Sleep medicine is perfectly positioned to leverage this tool due to the wealth of physiological signals obtained through sleep studies or sleep tracking devices and abundance of access...

Background We examined associations between dog ownership, morning dog walking and its timing and duration, and depression risk in female nurses, exploring effect modification by chronotype. We hypothesized that dog ownership and morning walking with the dog are associated with lower odds of depression, and that the latter is particularly beneficia...

Background Alzheimer’s disease (AD) causes disruption in the collective dynamics of the brain activities which can be captured by analyzing the functional interactions between electroencephalographic (EEG) signals in different regions of the brain. To better assess the AD‐related changes in the interactions, one possible approach is to increase the...

BACKGROUND The relationship between 24-h rest-activity rhythms (RAR) and risk for dementia or mild cognitive impairment (MCI) remains an area of growing interest. Previous studies, often limited by small sample sizes, short follow-ups, and older participants, has yet to fully explore the link between disrupted RAR and dementia/MCI in middle-aged an...

Simple Summary This study investigated the potential connection between working night shifts, sleep patterns, and the risk of thyroid cancer among nurses. The researchers followed over 114,000 women for 26 years and identified 588 cases of thyroid cancer. The study found that there was no link between working night shifts and thyroid cancer risk. H...

To review methods for analyzing circadian rest-activity patterns using actigraphy and to discuss their applications in large cohort and population-based studies. We reviewed several widely used approaches, including parametric analysis (i.e., cosinor model and wavelet analysis), nonparametric analysis, data adaptive approach (i.e., empirical mode d...

BACKGROUND Rates of poor sleep and hypertension are alarming worldwide. In this study, we investigate the association between sleeping difficulties and sleep duration with hypertension risk in women. METHODS Sixty-six thousand one hundred twenty-two participants of the NHS2 (Nurses’ Health Study 2), who were free of hypertension at baseline (2001)...

Introduction Alzheimer’s disease (AD) causes disruptions in brain functions, which can be tracked by proper analysis of electroencephalography (EEG). Current efforts to understand the impact of AD on brain activity have leveraged the development of high-density EEG. Alternatively, we propose that AD can be discriminated from healthy controls (HC) b...

Introduction Depression is an increasingly prevalent mental health condition. Patients with depression have disrupted rapid eye movement (REM) sleep as characterized by shortened REM latency, increased REM sleep duration, and increased REM density. However, it is unknown whether the dynamic patterns of EEG within REM episodes are altered in these p...

Breast cancer is highly prevalent yet a more complete understanding of the interplay between genes and probable environmental risk factors, such as night work, remains lagging. Using a discordant twin pair design, we examined the association between night shift work and breast cancer risk, controlling for familial confounding. Shift work pattern wa...

Background: Most existing automated sleep staging methods rely on multimodal data, and scoring a specific epoch requires not only the current epoch but also a sequence of consecutive epochs that precede and follow the epoch. Objective: We proposed and tested a convolutional neural network called SleepInceptionNet, which allows sleep classificati...

Bladder cancer is the sixth most common cancer in the United States. Night shift work has previously been linked with cancer risk. Whether there is an association between rotating night shift work and bladder cancer in women has not been studied previously. Eligible participants in the Nurses’ Health Study (NHS, n = 82,147, 1988–2016) and Nurses’ H...

Background Only few longitudinal studies with high risk of bias have examined relationship between pets and adolescents' mental health. Methods Our prospective cohort study followed depression-free US adolescents aged 12–18, enrolled in the Growing Up Today Study from pet ownership assessment in 1999 to possible occurrence of high depressive sympt...

An appreciable number of medicines have a recommended unique single time-of-day or asymmetrical or unequal-interval multiple-daily administration schedule. Many prescription and over-the-counter (OTC) products, according to administration time, can exert positive or negative impact on nighttime sleep and daytime wakefulness. Intuitively, medicines...

The sleep–wake cycle is regulated by circadian Process C and homeostatic Process S. Selective thermal stimulation (STS) of the cervical spine region enhances glabrous skin blood flow (GSBF) and augments body heat dissipation to increase distal‐to‐proximal skin gradient (DPG) causing decrease of core body temperature (CBT), which can shorten sleep o...

Introduction Most of the current automatic polysomnography sleep staging methods use multi-signal data and require a sequence of preceding and following epochs to score the stage of a specific epoch, which may not be desirable for analysis in real-time and/or in free-living conditions. We developed a deep learning-based sleep staging algorithm, nam...

Thermoregulation is a process that is essential to the maintenance of life for all warm-blooded mammalian and avian species. It sustains a constant core body temperature in the face of a wide array of environmental thermal conditions and intensity of physical activities that generate internal heat. A primary component of thermoregulatory function i...

Borbély proposed an interacting two-component model of sleep regulation comprising a homeostatic Process S and a circadian Process C. The model has provided understanding of the association between core body temperature (CBT) as a key element of Process C that is deterministic of sleep onset and offset. However, it additionally provides a new persp...

Borbély proposed an interacting two‐component model of sleep regulation comprising a homeostatic Process S and a circadian Process C. The model has provided understanding of the association between core body temperature (CBT) as a key element of Process C that is deterministic of sleep onset and offset. However, it additionally provides a new persp...

Background The emerging novel coronavirus disease 2019 (COVID-19) has become one of the leading cause of deaths worldwide in 2020. The present systematic review and meta-analysis estimated the magnitude of sleep problems during the COVID-19 pandemic and its relationship with psychological distress. Methods Five academic databases (Scopus, PubMed C...

Background: Performance of wrist actigraphy in assessing sleep not only depends on the sensor technology of the actigraph hardware but also on the attributes of the interpretative algorithm (IA). The objective of our research was to improve assessment of sleep quality, relative to existing IAs, through development of a novel IA using deep learning...

Introduction Several different interpretive algorithms (IAs) are available for scoring actigraphy-obtained body movement data for sleep and wake epochs. Although most have high sensitivity in detecting sleep epochs, they identify wake epochs poorly. We derived a machine learning (ML) based IA that improves differentiation of sleep and wake epoch to...

Background Estimation of sleep parameters by wrist actigraphy is highly dependent on performance of the interpretative algorithm (IA) that converts movement data into sleep/wake scores. Research Questions (1) Does actigraphy mode of operation -- Proportional Integrating Measure (PIM) or Zero Crossing Mode (ZCM), responsive respectively to intensit...

The rapid emergence of new measurement instruments and methods requires personnel and researchers of different disciplines to know the correct statistical methods to utilize to compare their performance with reference ones and properly interpret findings. We discuss the often-made mistake of applying the inappropriate correlation and regression sta...

We compared performance in deriving sleep variables by both Fitbit Charge 2™, which couples body movement (accelerometry) and heart rate variability (HRV) in combination with its proprietary interpretative algorithm (IA), and standard actigraphy (Motionlogger® Micro Watch Actigraph: MMWA), which relies solely on accelerometry in combination with it...

We compared performance of four popular interpretative algorithms (IAs), i.e., Cole–Kripke, Rescored Cole–Kripke, Sadeh, and UCSD, utilized to derive sleep parameters from wrist actigraphy data. We conducted in-home sleep study of 40 healthy adults (17 female/23 male; age 26.7 ± 12.1 years), assessing sleep variables both by Motionlogger® Micro Wat...

BACKGROUND Wearable sleep monitors are of high interest to consumers and researchers because of their ability to provide estimation of sleep patterns in free-living condition in a cost-efficient way. OBJECTIVE We conducted a systematic review of publications reporting performance of wristband Fitbit models in assessing sleep parameters and stages....

Background Wearable sleep monitors are of high interest to consumers and researchers because of their ability to provide estimation of sleep patterns in free-living conditions in a cost-efficient way. Objective We conducted a systematic review of publications reporting on the performance of wristband Fitbit models in assessing sleep parameters and...

Elevated asleep heart rate (HR) is a risk factor for cardiovascular disease and other-cause morbidity and mortality. We assessed the accuracy of Fitbit Inc. PurePulse® photoplethysmography with reference to three-lead electrocardiography (ECG) in determining HR during sleep. HR of 35 (17 female) healthy adults 25.1 ± 10.6 years of age (mean ± SD) w...

Water-based passive body heating (PBHWB) as a warm shower or bath before bedtime is often recommended as a simple means of improving sleep. We searched PubMed, CINAHL, Cochran, Medline, PsycInfo, and Web of Science databases and extracted pertinent information from publications meeting predefined inclusion and exclusion criteria to explore the effe...

The present research proposes an effective method to enhance the heat transport capability of conventional electronic coolers and improve their thermal management. Pulsating heat pipes (PHPs) are outstanding heat transfer devices in the field of electronic cooling. In the present study, two sets of open-loop pulsating heat pipes (OLPHPs) for two di...

The increasing need for small-scale devices for use in areas of chemical, biological and environmental viewing systems has caused a large amount of researches in this area. Part of these researches is devoted to the micro-pumps. Mercury electromagnetically stimulated micro-pump is a new type of micro-pumps. These are based on a reciprocating motion...

The benefits of using electromagnetic force in micro-pumps led to produce Magneto Hydro Dynamic micro-pumps. The function of these micro-pumps is based on the magnetic force which is applied to the mass of mercury existent in micro cavities connected to the micro-channel. This research experiments on the role of outlet micro cavity angle in the amo...