Duclos et al. (2014) “Rest-activity cycle disturbances in the acute phase of a moderate to severe traumatic brain injury”


Sleep-wake disturbances are among the most persistent sequelae after traumatic brain injury (TBI) and probably arise during the hospital stay following TBI. These disturbances are characterized by difficulties sleeping at night and staying awake during the day.


The aim of the present study was to document rest-activity cycle consolidation in acute moderate/severe TBI using actigraphy and to assess its association with injury severity and outcome.


In all, 16 hospitalized patients (27.1 ± 11.3 years) with moderate/severe TBI wore actigraphs for 10 days, starting in the intensive care unit (ICU) when continuous sedation was discontinued and patients had reached medical stability. Activity counts were summed for daytime (7:00-21:59 hours) and nighttime periods (22:00-6:59 hours). The ratio of daytime period activity to total 24-hour activity was used to quantify rest-activity cycle consolidation. An analysis of variance was carried out to characterize the evolution of the daytime activity ratio over the recording period.


Rest-activity cycle was consolidated only 46.6% of all days; however, a significant linear trend of improvement was observed over time. Greater TBI severity and longer ICU and hospital lengths of stay were associated with poorer rest-activity cycle consolidation and evolution. Patients with more rapid return to consolidated rest-activity cycle were more likely to have cleared posttraumatic amnesia and have lower disability at hospital discharge.


Patients with acute moderate/severe TBI had an altered rest-activity cycle, probably reflecting severe fragmentation of sleep and wake episodes, which globally improved over time. A faster return to rest-activity cycle consolidation may predict enhanced brain recovery.

PDF: Duclos2014_TBI_Rest-activity

CITATION: Duclos C, Dumont M, Blais H, Paquet J, Laflamme E, De Beaumont L, Wiseman-Hakes C, Menon DK, Bernard F, Gosselin N. Rest-activity cycle disturbances in the acute phase of a moderate to severe traumatic brain injury, Neurorehabilitation and Neural Repair, DOI: 10.1177/1545968313517756

Disrupted Sleep Could Spur Cancer Growth Through Immune System Effects

Disrupted Sleep Could Spur Cancer Growth Through Immune System Effects, Animal Study Shows.


Disrupted sleep could accelerate cancer growth due to its negative effects on the immune system, according to new research in mice. In the study, published in the journal Cancer Research, researchers split mice into two groups. One group of mice was allowed to sleep peacefully during the day (mice are nocturnal and typically sleep in the daytime), while the other mice had their sleep disturbed every two minutes with a motorized brush that swept through their cages; these mice were forced to wake up and go back to sleep. 

The mice experienced these settings for seven days before being injected with cells from one of two different kinds of tumors. After being injected, all the mice went on to develop tumors within nine to 12 days; the researchers examined the tumors four weeks later. The tumors that came from the mice whose sleep was disturbed were twice as big as the ones from the mice who were not disturbed, researchers found.

‘Placebo Sleep’ Can Improve Cognitive Skills | Popular Science


‘Placebo Sleep’ Can Improve Cognitive Skills | Popular Science.

Kiwi: Superfood for Sleep?

Kiwi: Superfood for Sleep?


Bluetooth Headset Vigo Knows When You Are Tired Before You Do | TechCrunch

Bluetooth Headset Vigo Knows When You Are Tired Before You Do | TechCrunch.

BBC News – Are you a lark or an owl? Genetic link found

yawning cartoon

BBC News – Are you a lark or an owl?.

What fat mice tell us: Link between body clock and gaining weight

What fat mice tell us: Link between body clock and gaining weight.

Gene research: Tests will focus on the Y6 gene and the extent that it determines the amount of fat stored in the body.


The body clock may be more influential than previously thought, with researchers finding that it could also play a role in how fat we become and contribute to the risk of diseases such as diabetes.

Researchers from the Garvan Institute of Medical Research in Sydney have found a specific gene which regulates the body clock also plays a role in growth hormone production. The Y6 gene is highly expressed in the only part of the brain known to control the body’s circadian rhythm. However, molecular biologist Herbert Herzog said little was known about the Y6 gene.

Read more: http://www.smh.com.au/lifestyle/diet-and-fitness/what-fat-mice-tell-us-link-between-body-clock-and-gaining-weight-20140108-30hnp.html#ixzz2pqYpuZA5