The impact of APOE-ε polymorphism on the interaction between sleep, circadian rhythmicity and cognition in healthy elderly people.


PhD student: Adriana Michalak

Supervisors: A/Prof Alpar Lazar and Professor Michael Hornberger

Affiliations: Sleep and Brain Research Unit, Faculty of Medicine and Health Sciences, University of East Anglia 



Alzheimer's disease (AD) is the most common type of dementia manifesting mainly over the age of 65 with no curative treatment available. Sleep abnormalities are common in AD and can emerge early in the disease process. As such the APOE-ε4 allele, a genetic risk factor for AD has been recently associated with impaired sleep and cognitive deficits such as episodic memory, executive functions and spatial navigation in healthy adults. Given the important role of sleep in brain function, early sleep deficits could play a mechanistic role in the development of AD. Nevertheless, the cause of early sleep disturbances and their impact on cognition in healthy people at increased genetic risk of developing AD is unknown. Importantly, sleep alterations are modifiable what allows development of potential treatments aiming to slow-down and even prevent development of AD.

Objectives of the study: To investigate the effect of sleep-wake homeostasis and circadian rhythms on brain activity and cognitive performance in healthy elderly at low and high genetic risk of developing AD. 

Data collection methods: We have been recruiting elderly participants between 40 and 90 years of age. Following an extensive screening session including 1-hour-long face-to-face cognitive assessment and one hour of questionnaire session, 40 participants carrying either the low (APOE-ε3) or the high-risk (APOE-ε4) alleles undergo a two-week-long home-based session wearing motion sensor to assess habitual sleep-wake rhythmicity (an actigraphy session). This is followed by a 2.5 day-long laboratory session consisting of either a sleep deprivation or a multi-nap protocol, which experimentally increase or minimize homeostatic sleep pressure, respectively. We called also measures of sleep and wake-dependent brain electric activity, cognitive performance and circadian rhythmicity (i.e. saliva melatonin).



e-mail: | 

Effects of Sleep loss and time of day on postural control: A randomized controlled sleep deprivation vs multinap study in healthy older men and women.


PhD student: Z. Shabana

Supervisors:  A/Prof Alpar Lazar and Prof Michael Grey

Affiliations: Sleep and Brain Research Unit, Faculty of Medicine and Health Sciences, University of East Anglia 


Falls represent a major public health problem leading to injuries, hospitalization and reduced quality of life. The risk of falls increases with age and frailty level. Studies suggest that sleep deprivation increases postural instability and this effect is greater in older individuals. While reliance on vision for postural control increases with age, the benefit of sensory augmentation by light fingertip haptic feedback does too. The contribution of sleep-wake homeostasis and circadian rhythmicity on postural control with effects on the sensorimotor system and their interaction with sex and sensory feedback in older adults is unknown. The study aim to investigate these effects.




Investigation into the genetic bases of evening chronotype and its effect on mental health and intelligence.


MSc by Research: Monika Wojtachnio

Supervisors:  A/Prof Alpar Lazar and Prof Tamas Dalmay

Affiliations: Sleep and Brain Research Unit, Faculty of Medicine and Health Sciences, University of East Anglia 



Being an evening or morning person represents an individual’s underlying circadian rhythm. This rhythm manifests itself through a range of behavioural and biological functions, from socialization and productivity, through sleep-wake patterns, hormone secretion, and body temperature to gene expression. It varies from person to person, creating a continuum of the diurnal (time-of-day) preferences, called chronotype. There are three main chronotypes: morning, intermediate, and evening, with some extreme cases at each end of the spectrum. Furthermore, it is now known that circadian preference is related to both physical and mental health. Eveningness has been found to be associated with lower sleep quality, higher BMI, increased risk of depression, bipolar disorder, anxiety and addictive disorders. This study is looking at the genetic bases of chronotype and will be investigating polymorphisms in the well-known circadian genes PER3 and CRY1 to possibly uncover new links between genetics and chronotype. We will also be investigating the associations with mental health and cognitive ability to see if there is any relationship between those, genetics and chronotype, especially in evening type individuals. 


Do you think you’re an evening type person and would be happy to contribute to a research study?

Volunteers are needed for a short study on sleep, clock genes, chronotype and psychological function (i.e. mental health and intelligence).

The study involves filling in a few questionnaires, taking a short non-verbal intelligence test and providing a buccal swab. It’s as simple as that! If you complete this study you will also be entered into a raffle to win up to 100£.

Interested? For further details contact Monika Wojtachnio at



Feasibility of Paradoxical Intention Therapy among adults with insomnia and high sleep effort.


Doctorate in Clinical Psychology: Glenneze Ong

Supervisors:  A/Prof Alpar Lazar and Prof Niall Broomfield

Affiliations: Sleep and Brain Research Unit, Faculty of Medicine and Health Sciences, University of East Anglia 



Having poor sleep quality is an increasingly common experience among adults. Just in the UK, insomnia is a highly prevalent sleep disorder that affects at least a third of the population. One reason why adults may struggle with poor sleep or insomnia is due to having high sleep effort, which is when one actively tries to control their sleep. For example, adults who have high sleep effort may try forcing themselves to fall asleep or worry about the consequences of not sleeping whilst they are in bed. As sleep should be a naturally occurring process, the active control of sleep paradoxically makes it difficult for one to fall asleep. Unsurprisingly, consistently having poor sleep can negatively impact various aspects of life, particularly one’s mental health.


This study aims to test the feasibility of a sleep intervention known as Paradoxical Intention Therapy that specifically targets high sleep effort in adults who struggle with falling or staying asleep at night. There are two parts to this study: survey and intervention. The first part of the study requires you to fill in a set of online questionnaires asking about your demographic information, sleep quality and mental health. Later on, those who meet the criteria for sleep difficulties (insomnia) and high sleep effort will have the opportunity to receive Paradoxical Intention Therapy to improve their sleep quality.



For more information or if you are interested to take part, please get in touch with Glenneze Ong at


Would you like to get engaged?

We are continuously recruiting participants! If you are interested in volunteering in any of our projects please send an email to so we can contact you.