Circadian rhythm of temperature in head injury

Abstract

It has been shown in a previous study that head injured patients appear to have a circadian rhythm of their body functions. This needed to be confirmed using additional data, better collection methods and analysis. Additional goals were to develop a method of detrending of physiological time series in order to improve rhythm detection when it may be hidden behind a low frequency trend and the creation of a computer system for data acquisition and analysis. The temperature data of 10 head injured patients was studied using the Iterative Cosinor method. In one case, prior to the Cosinor method, detrending of the data was used using a specially designed polynomial fitting technique. The Iterative Cosinor method showed circadian rhythms in nine out of 10 patients. After detrending, a rhythm was found in the data of the 10th patient as well. The periods of the rhythm were around, but were not equal to, 24 hours. The results show that comatose head injured patients have a circadian rhythm of their core temperature. The detection of a circadian rhythm may, in some cases, be improved by using a detrending technique. The deviation of the rhythm period from 24 hours suggests that the rhythms found in these patients are free-running, meaning that head injured patients are not synchronized with their surroundings.

Study of Brain Circadian Rhythms in Patients with Chronic Disorders of Consciousness and Healthy Individuals Using Microwave Radiometry

“…Brain damage can lead to disturbances in cerebral circadian rhythms, which was demonstrated using temperature sensors implanted in the brain parenchyma. A better outcome was shown in patients with preserved circadian rhythm and higher mesor (mean level) values, [ 6 , 7 ] which coincides with another study with similar results in half of the patients after severe traumatic brain injury (TBI) with maintained circadian rhythm of cerebral and body temperature [ 8 , 9 ]. These studies emphasize the importance of circadian rhythms, the presence of which reflects the higher potential of one’s own reparative responses.…”

Prognostic Value of Circadian Brain Temperature Rhythm in Basal Ganglia Hemorrhage After Surgery

“…Cosinor analysis was strictly performed a 24-h intervals in this study, which is the most commonly used model for describing rhythmic temperature patterns. Studies involving brain injury patients support a period OR Odds ratio, CI confidence interval *p \ 0.05, **p \ 0.01 a Functional outcome, defined as unfavorable/favorable ratio, with favorable outcome defined as mRS score 0-2 at 12 months after surgery, and unfavorable outcome as mRS score 3-6 at 12 months after surgery b Survival outcome, defined as the alive/dead ratio, was followed up at 12 months after surgery c Intact rhythm of BT was defined as fitting the p value of the cosinor analysis (p \ 0.05) for brain temperature of approximately 24 h for body temperature and BP assessment [38][39][40]. Our study identified a mesor [ 37.5 °C in 66.6% of patients.…”

“…Cosinor analysis was strictly performed a 24-h intervals in this study, which is the most commonly used model for describing rhythmic temperature patterns. Studies involving brain injury patients support a period of approximately 24 h for body temperature and BP assessment [ 38 – 40 ]. Our study identified a mesor > 37.5 °C in 66.6% of patients.…”

Temperature Rhythm in Aneurysmal Subarachnoid Hemorrhage

“…The 24-h fixed period cosinor is the most commonly used and interpretable model to describe diurnal temperature patterns in adults and is well established as an effective model for this purpose. Studies of mixed brain injury and intensive care patients support that a period of approximately 24 h is present in this group of patients [21][22][23][24][25][26]. The 24-h fixed model should thus be useful to identify overt 24-h temperature pattern disruptions that might occur as a result of brain insult and the impact of medical care, nursing care, and the intensive care clinical environment.…”