Sleep in traumatic brain injury

Persistent CO2 reactivity deficits are associated with neurological dysfunction up to one year after repetitive mild closed head injury in adolescent mice

Cerebrovascular reactivity (CVR) deficits in adolescents with concussion may persist after resolution of neurological symptoms. Whether or not CVR deficits predict long term neurological function is unknown. We used adolescent mice closed head injury (CHI) models (54 g, 107 cm or 117 cm drop height), followed by blood oxygenation level dependent (BOLD)-functional MRI with CO₂ challenge to assess CVR and brain connectivity. At one week, 3HD 107 cm mice showed delayed BOLD responses (p = 0.0074), normal striatal connectivity_, and an impaired respiratory rate response to CO₂ challenge (p = 0.0061 in ΔRmax). The 107 cm group developed rotarod deficits at 6 months (p = 0.02) and altered post-CO₂ brain connectivity (3-fold increase in striatum to motor cortex correlation coefficient) by one year, but resolved their CVR and respiratory rate impairments, and did not develop cognitive or circadian activity deficits. In contrast, the 117 cm group had persistent CVR (delay time: p = 0.016; washout time: p = 0.039) and circadian activity deficits (free-running period: 23.7 hr in sham vs 23.9 hr in 3HD; amplitude: 0.15 in sham vs 0.2 in 3HD; peak activity: 18 in sham vs 21 in 3HD) at one year. Persistent CVR deficits after concussion may portend long-term neurological dysfunction. Further studies are warranted to determine the utility of CVR to predict chronic neurological outcome after mild traumatic brain injury.

Sleep disorders in traumatic brain injury

The purpose of the review is to collect the most relevant current literature on the mechanisms of normal sleep and sleep disorders associated with traumatic brain injury (TBI), to discuss the most frequent conditions and the evidence on their possible treatments and future research. Sleep disorders are extremely prevalent after TBI (30-84%). Insomnia and circadian rhythm disorders are the most frequent disorders among the population that has suffered mild TBI, while hypersomnolence disorders are more frequent in populations that have suffered moderate and severe TBI. The syndrome of obstructive sleep apnea and restless leg syndrome are also very frequent in these patients; and patients exposed to multiple TBIs (war veterans) are especially susceptible to sleep disorders. The treatment of these disorders requires taking into account the particularities of these patients. In conclusion, diagnosis and treatment of sleep disorders should become part of routine clinical practice and cease to be anecdotal (as it is today) in patients with TBI. In addition, it is necessary to continue carrying out research that reveals the best therapeutic approach to these patients.

Sleep disorders in traumatic brain injury

The purpose of the review is to collect the most relevant current literature on the mechanisms of normal sleep and sleep disorders associated with traumatic brain injury (TBI), to discuss the most frequent conditions and the evidence on their possible treatments and future research. Sleep disorders are extremely prevalent after TBI (30-84%). Insomnia and circadian rhythm disorders are the most frequent disorders among the population that has suffered mild TBI, while hypersomnolence disorders are more frequent in populations that have suffered moderate and severe TBI. The syndrome of obstructive sleep apnea and restless leg syndrome are also very frequent in these patients; and patients exposed to multiple TBIs (war veterans) are especially susceptible to sleep disorders. The treatment of these disorders requires taking into account the particularities of these patients. In conclusion, diagnosis and treatment of sleep disorders should become part of routine clinical practice and cease to be anecdotal (as it is today) in patients with TBI. In addition, it is necessary to continue carrying out research that reveals the best therapeutic approach to these patients.

The interaction of the circadian and immune system: Desynchrony as a pathological outcome to traumatic brain injury

Traumatic brain injury (TBI) is a complex and costly worldwide phenomenon that can lead to many negative health outcomes including disrupted circadian function. There is a bidirectional relationship between the immune system and the circadian system, with mammalian coordination of physiological activities being controlled by the primary circadian pacemaker in the suprachiasmatic nucleus (SCN) of the hypothalamus. The SCN receives light information from the external environment and in turn synchronizes rhythms throughout the brain and body. The SCN is capable of endogenous self-sustained oscillatory activity through an intricate clock gene negative feedback loop. Following TBI, the response of the immune system can become prolonged and pathophysiological. This detrimental response not only occurs in the brain, but also within the periphery, where a leaky blood brain barrier can permit further infiltration of immune and inflammatory factors. The prolonged and pathological immune response that follows TBI can have deleterious effects on clock gene cycling and circadian function not only in the SCN, but also in other rhythmic areas throughout the body. This could bring about a state of circadian desynchrony where different rhythmic structures are no longer working together to promote optimal physiological function. There are many parallels between the negative symptomology associated with circadian desynchrony and TBI. This review discusses the significant contributions of an immune-disrupted circadian system on the negative symptomology following TBI. The implications of TBI symptomology as a disorder of circadian desynchrony are discussed.

Injury, Sleep, and Functional Outcome in Hospital Patients With Traumatic Brain Injury

PROBLEM

Uninterrupted nighttime sleep is associated with better cognition and functional outcomes in healthy adults, but the relationship between sleep and functional outcome in individuals hospitalized with severe traumatic brain injury (TBI) remains to be clarified.

OBJECTIVE

The aims of this study were to (1) describe nighttime rest-activity variables-wake bouts (counts), total wake time (minutes), and sleep efficiency (SE) (percentage; time asleep/time in bed)-in people on a neuroscience step-down unit (NSDU) post-TBI and (2) describe the association between injury and nighttime rest-activity on post-TBI functional outcome (using Functional Independence Measure [FIM] at discharge from inpatient care).

METHODS

This study is a cross-sectional, descriptive pilot study. We recruited participants from the NSDU (n = 17 [age: mean (SD), 63.4 (17.9)]; 82% male, 94% white) who wore wrist actigraphy (source of nighttime rest-activity variables) for up to 5 nights. For injury variables, we used Glasgow Coma Scale (GCS) score and Injury Severity Score (ISS). We used Spearman ρ and regression to measure associations.

RESULTS

Glasgow Coma Scale mean (SD) score was 8.8 (4.9), ISS mean (SD) score was 23.6 (6.7), and FIM mean (SD) score was 48 (14.5). Averages of nighttime rest-activity variables (8 PM-7 AM) were as follows: SE, 73% (SD, 16); wake bouts, 41 counts (SD, 18); total wake time, 74 minutes (SD, 47). Correlations showed significance between FIM and GCS (P = .005) and between SE and GCS (P = .015). GCS was the only statistically significant variable associated with FIM (P = .013); we eliminated other variables from the model as nonsignificant (P > .10). Sleep efficiency and FIM association was nonsignificant (P = .40). In a separate model (ISS, GCS, and SE [dependent variable]), GCS was significant (P = .04), but ISS was not (P = .25).

CONCLUSION

Patients with severe TBI on the NSDU have poor actigraphic sleep at night. GCS has a stronger association to functional outcome than nighttime rest-activity variables.

The interplay between neuroendocrine and sleep alterations following traumatic brain injury

BACKGROUND

Sleep and endocrine disruptions are prevalent after traumatic brain injury (TBI) and are likely to contribute to morbidity.

OBJECTIVE

To describe the interaction between sleep and hormonal regulation following TBI and elucidate the impact that alterations of these systems have on cognitive responses during the posttraumatic chronic period.

METHODS

Review of preclinical and clinical literature describing long-lasting endocrine dysregulation and sleep alterations following TBI. The bidirectional relationship between sleep and hormones is described. Literature describing co-occurrence between sleep-wake disturbances and hormonal dysregulation will be presented. Review of literature describing cognitive effects of seep and hormones. The cognitive and functional impact of sleep disturbances and hormonal dysregulation is discussed within the context of TBI.

RESULTS/CONCLUSIONS

Sleep and hormonal alterations impact cognitive and functional outcome after TBI. Diagnosis and treatment of these disturbances will impact recovery following TBI and should be considered in the post-acute rehabilitative setting.