Proven Expertise / Client Projetcs
Melatonin and circadian rhythms in autism: Case report
Abstract: Among the most co-occurring conditions in autism spectrum disorders (ASD), there are sleep disorders which may exacerbate associated behavioral disorders and lead to intensification of existing autistic symptoms. Several studies investigating the use of melatonin in the treatment of sleep disorders in ASD have shown comparative efficiency in sleep with little or no side effects. Here we report a case of ASD with non-24-hour rhythm and the effect of melatonin in circadian parameters by actigraphy. Visual analysis of the first 10 days recorded and the periodogram suggest that this patient showed a non-24-hour rhythm. This ASD subject showed before melatonin administration an activity/rest rhythm lower than 24 hours.
Modification of a personal dosimetry device for logging melanopic irradiance
Abstract: Performance characterisations were carried out before and after a modification to the optics of the Condor Instruments’ ActTrust light and activity data loggers to improve the spectral performance for measuring melanopic-weighted irradiance in non-visual studies. The results confirm the intended improvement, so that the device provides the best-known single-sensor match to the melanopic response. In addition, the device includes a separate sensor which remained well-matched for illuminance logging.
Nocturnal motor activity and light exposure: Objective actigraphy-based marks of melancholic and non-melancholic depressive disorder. Brief report
Abstract: Differentiation of melancholic (MEL) and non-melancholic (N-MEL) depression results from subjective assessment of psychomotor disturbance, which obscures their accurate diagnosis. CORE instrument assigned participants with severe or refractory depression to MEL or N-MEL group. Participants underwent 7 days of actigraphy. Data was fitted to a cosinusoidal curve corresponding to a 24-h rhythm. Nocturnal activity was significantly higher in N-MEL. ROC curve shows that average night activity discriminate participants with 71% sensitivity and 100% specificity (area under the curve = 0.84). Actigraphy contribute to the objective differentiation of depression subtypes, and have implications for research on their neurobiology and clinical management.
Non-visual effects of light: How to use light to promote circadian entrainment and elicit alertness
Abstract: In addition to stimulating the visual system, light incident on the retina stimulates other biological functions, also referred to as non-visual responses. Among the most notable biological functions are human circadian rhythms, which are bodily rhythms that, in constant darkness, oscillate with a period close to, but typically slightly longer than 24 hours. Twenty-four-hour light–dark patterns incident on the retina are the major synchroniser of circadian rhythms to the local time on Earth. Entrainment of circadian rhythms has been implicated in health and well-being. Light can also elicit an acute alerting effect on people, similar to a ‘cup of coffee.’ This review summarises the literature on how light affects entrainment and alertness and how it can be used to achieve these aims.
Optical performance characterization of light-logging actigraphy dosimeters
Abstract: There are several wearable products specially developed or marketed for studying sleep, circadian rhythms, and light levels. However, new recommendations relating to human physiological responses to light have changed what measurements researchers may demand. The performances of 11 light-logging dosimeters from eight manufacturers were compared. The directional and spectral sensitivities, linearity, dynamic range, and resolution were tested for seven models, and compared along with other published data. The sample mainly comprised light-logging actigraphy dosimeters wearable as badges, in accordance with measurement protocols for larger-scale field studies. A proposed standard for optical performance assessments is set out.
Project and Construction of a Device to Measure Illuminance Levels and Temperature for the Study of Human Biological Rhythms
Abstract: This paper presents the conception, project and construction of a device capable of measuring different parameters for a study regarding changes in human biological rhythms for people in prolonged exposure to artificial illumination. The collected date includes luminosity and temperature of hospital rooms, following the criteria established by the research project of the Hospital de Clínicas de Porto Alegre. These parameters’ sensors are connected to two types of microcontrollers, both capable of storing and transmitting the collected data for further analysis.
Relationship between the level of knowledge about sleep and the habits and quality of sleep, and the components of attention in university students
Abstract: The delayed sleep phase, characterized by later sleeping and waking hours, seen in adolescence, may persist after the youths’ entry into university. This delay is associated to a reduction on sleep duration in students of morning shift, since they must wake-up earlier on school days. This behavior can modify the habits and quality of sleep and thus, cause damage in the attention of those of the morning shift. Knowing that attention is a basic process capable of interfering in other cognitive processes and that knowledge acts in decision making, we investigate the relationship between the level of knowledge about sleep and habits and the quality of sleep, and the components of attention in young people from an RN public university.
Relationship between exposure to light in the classroom, sleep-wake cycle and attention in adolescents from different cities in RN
Abstract: In adolescents, sleep phase delay is associated with reduced sleep duration, causing increased daytime sleepiness and poor academic performance. Low performance may be related to reduced attention, cognitive process, whose components present circadian variation, and as well as the sleep-wake cycle (SCA) may be modulated by dark light cycles. Therefore, this study aims to verify the existence of relationships between the luminous intensity in the classroom and the CSV, quality of sleep, daytime sleepiness and attention in adolescents in the morning shift of private schools in the capital (C) (Natal: Latitude: 05º 47′ 42″ South, Longitude: 35º 12′ 34″ West) and the interior (I) (Santa Cruz: Latitude: 6° 13′ 46” South, Longitude: 36° 1′ 24” West) of the State of RN. A total of 115 adolescents (C: 56 and I: 59), of both sexes (41 boys), enrolled in the 1st and 2nd years of high school participated in the study.
Rhythmic changes in Fabry disease: Inversion and non-oscillatory pattern in 6-sulfatoxymelatonin daily profile
Abstract: Fabry disease is a progressive disease characterized by an enzymatic deficiency of acid alpha-galactosidase and glycosphingolipids storage within the lysosomes. The disease has two phenotypes: classic and nonclassic. Excessive daytime sleepiness is a common sign reported by patients and can be caused by a circadian rhythm sleep disorder. Activity and rest cycle, variation of body temperature and melatonin biosynthesis are known rhythmicity markers. In the face of these evidences, our goal was to evaluate the rhythmic profile in Fabry’s disease patients using rhythmicity markers.
Sleep and light exposure across different levels of urbanisation in Brazilian communities
Abstract: Quilombos are settlements originally founded by Africans and African descendants (Quilombolas) in remote parts of Brazil to escape slavery. Due to individual histories, Quilombos nowadays exhibit different states of industrialisation, making them ideal for studying the influence of electrification on daily behaviour. In a comparative approach, we aimed to understand whether and how human sleep changes with the introduction of artificial light. We investigated daily rest-activity-rhythms and sleep-patterns in the Quilombolas’ by both wrist actimetry and the Munich ChronoType Questionnaire (MCTQ; the results of these two instruments correlated highly).
SleepData – Sleep Disorders Clinical Platform
Abstract: This dissertation presents the design and development of SleepData, a new information platform for managing clinical information on sleep disorders. The platform can integrate data from multiple sources produced by a diversity of monitoring devices and lab tests. SleepData provides tools for statistical analysis and diagnostic support tools specially designed to study patients with delayed sleep phase disorder (DSPD) and insomnia.
Social jetlag impairs balance control
Abstract: We assessed the impact of a common sleep disturbance, the social jetlag, on postural control during a period involving workdays and free days. The sleep habits of 30 healthy subjects were registered with a wrist actimeter for nine days (starting on Friday) and they participated in a set of four postural control tests carried out on Friday and on Monday. In addition, the subjects filled questionnaires about their sleep conditions and preferences. Actimetry measurements were used to calculate the Mid Sleep Phase (MSP). The difference between the MSP values on the workdays and free days measures the social jetlag. There were significant differences in sleep variables between workdays and free days. Postural control performance improved on Monday, after free sleep over the weekend, when compared with the tests performed on Friday. It seems that social jetlag affects brain areas involved in the control of posture, such as thalamus and the prefrontal cortex as well as the cerebellum, resulting in a worse performance in postural control. The performance improvement in the posture tests after the free days could be attributed to a lower sleep debt.
The Psychological and Physiological Part of Emotions: Multimodal Approximation for Valence Classification
Abstract: In order to develop more precise and functional affective applications, it is necessary to achieve a balance between the psychology and the engineering applied to emotions. Signals from the central and peripheral nervous systems have been used for emotion recognition purposes, however, their operation and the relationship between them remains unknown. In this context, in the present work we have tried to approach the study of the psychobiology of both systems in order to generate a computational model for the recognition of emotions in the dimension of valence. To this end, the electroencephalography (EEG) signal, electrocardiography (ECG) signal and skin temperature of 24 subjects have been studied.
The Use of Actigraphy for Risk Stratification in Pediatric Obstructive Sleep Apnea
Abstract: Sleep disordered breathing (SDB) in children is a spectrum of abnormal breathing patterns, characterized by a limitation of airflow during sleep. Upper airway resistance and collapse of the pharynx can cause varying degrees of obstruction, which can be exacerbated by the presence of adenotonsillar hypertrophy, obesity, and craniofacial or neuromuscular disorders. The spectrum of SDB ranges from primary snoring (PS), to upper airway resistance syndrome (UARS), to the most severe diagnosis of obstructive sleep apnea (OSA).1 Obstructive sleep apnea can be further stratified into mild, moderate, and severe categories. This spectrum is based on the frequency and severity of airflow obstructions, arousals, and gas exchange abnormalities during sleep.
Validation of a national actigraphy
Abstract: The actor consists of a pulse device equipped with an accelerometer, a microprocessor and an internal memory, which are capable of detecting and storing motion recording. Actigraphy is used in the evaluation of sleep disorders such as circadian rhythm disorders, insomnia and excessive daytime sleepiness. This method has some advantages over polysomnography, such as a longer evaluation period, simplicity of use and interpretation, and low cost. This study aims to validate the ActTrust actigrapher in the evaluation of sleep and wakefulness, comparing him with polysomnography.