Regulatory and autoregulatory physiological dysfunction as a primary characteristic of post concussion syndrome: Implications for treatment

Transcranial low-level laser therapy improves neurological performance in traumatic brain injury in mice: effect of treatment repetition regimen

Low-level laser (light) therapy (LLLT) has been clinically applied around the world for a spectrum of disorders requiring healing, regeneration and prevention of tissue death. One area that is attracting growing interest in this scope is the use of transcranial LLLT to treat stroke and traumatic brain injury (TBI). We developed a mouse model of severe TBI induced by controlled cortical impact and explored the effect of different treatment schedules. Adult male BALB/c mice were divided into 3 broad groups (a) sham-TBI sham-treatment, (b) real-TBI sham-treatment, and (c) real-TBI active-treatment. Mice received active-treatment (transcranial LLLT by continuous wave 810 nm laser, 25 mW/cm², 18 J/cm², spot diameter 1 cm) while sham-treatment was immobilization only, delivered either as a single treatment at 4 hours post TBI, as 3 daily treatments commencing at 4 hours post TBI or as 14 daily treatments. Mice were sacrificed at 0, 4, 7, 14 and 28 days post-TBI for histology or histomorphometry, and injected with bromodeoxyuridine (BrdU) at days 21–27 to allow identification of proliferating cells. Mice with severe TBI treated with 1-laser Tx (and to a greater extent 3-laser Tx) had significant improvements in neurological severity score (NSS), and wire-grip and motion test (WGMT). However 14-laser Tx provided no benefit over TBI-sham control. Mice receiving 1- and 3-laser Tx had smaller lesion size at 28-days (although the size increased over 4 weeks in all TBI-groups) and less Fluoro-Jade staining for degenerating neurons (at 14 days) than in TBI control and 14-laser Tx groups. There were more BrdU-positive cells in the lesion in 1- and 3-laser groups suggesting LLLT may increase neurogenesis. Transcranial NIR laser may provide benefit in cases of acute TBI provided the optimum treatment regimen is employed.

Heart Rate Variability Biofeedback for Postconcussion Syndrome: Implications for Treatment

Heart Rate Variability (HRV) Biofeedback is used to restore balance in the activity of the sympathetic and parasympathetic branches of the autonomic nervous system by increasing or reducing the activity of either. Researchers have postulated that a fundamental cause of refractory postconcussion syndrome (PCS) is physiologic dysfunction that fails to return to normal after concussion. The primary physiologic issues identified have been altered autonomic function and impaired cerebral autoregulation. Evidence has shown that aerobic exercise training increases parasympathetic activity, reduces sympathetic activation, and improves cerebral blood flow so it may, therefore, help to reduce concussion-related physiological dysfunction. The authors hypothesize that HRV biofeedback training will ameliorate PCS by improving autonomic balance as well as cerebral autoregulation, and that there will be a relationship between increased interval variability and postconcussion symptom reduction.

Early postinjury exercise reverses memory deficits and retards the progression of closed-head injury in mice

Closed-head injury (CHI) usually involves both physical damage of neurons and neuroinflammation. Although exercise promotes neuronal repair and suppresses neuroinflammation, CHI patients currently often remain resting during the post-traumatic period. This study aimed to investigate whether and how postinjury exercise benefited the brain structure and function in mice after CHI. Closed-head injury immediately caused an elevated neurological severity score, with rapid loss of object recognition memory, followed by progressive location-dependent brain damage (neuronal loss and activation of microglia in the cortex and hippocampus). An early exercise protocol at moderate intensity (starting 2 days postimpact and lasting for 7 or 14 days) effectively restored the object recognition memory and prevented the progressive neuronal loss and activation of microglia. However, if the exercise started 9 days postimpact, it was unable to recover recognition memory deficits. In parallel, early exercise intervention drastically promoted neurite regeneration, while late exercise intervention was much less effective. We also tested the possible involvement of brain-derived neurotrophic factor (BDNF) and mitogen-activated protein kinase phosphatase-1 (MKP-1) in the exercise-induced beneficial effects. Exercise gradually restored the impact-abolished hippocampal expression of BDNF and MPK-1, while oral administration of triptolide (a synthesis inhibitor of MKP-1 and an antagonist of nuclear factor-B) before each bout of exercise blocked the restorative effects of exercise on MKP-1 and recognition memory, as well as the exercise-induced retardation of neuronal loss. Although triptolide treatment alone inhibited activation of microglia and maintained neuronal numbers, it did not recover the injury-hampered recognition memory. Overall, moderate exercise shortly after CHI reversed the deficits in recognition memory and prevented the progression of brain injury.

Examining Emotional Sequelae of Sport Concussion

Depression, fatigue, irritability, confusion, and general mood disturbance are frequently reported after cerebral concussion in sport. Recent trends in research point to the importance of examining postconcussive emotional disturbances more thoroughly, empirically, and clinically. An overview of the complexity of human emotion and its study is provided herein, followed by a review of emotional correlates identified in the existing sparse literature. The significance and clinical implications of identifying emotional correlates of concussion in sport and athletics are discussed.

Physical exercise ameliorates deficits induced by traumatic brain injury

The extent and depth of traumatic brain injury (TBI) remains a major determining factor together with the type of structural insult and its location, whether mild, moderate or severe, as well as the distribution and magnitude of inflammation and loss of cerebrovascular integrity, and the eventual efficacy of intervention. The influence of exercise intervention in TBI is multiple, ranging from anti-apoptotic effects to the augmentation of neuroplasticity. Physical exercise diminishes cerebral inflammation by elevating factors and agents involved in immunomodulatory function, and buttresses glial cell, cerebrovascular, and blood-brain barrier intactness. It provides unique non-pharmacologic intervention that incorporate different physical activity regimes, whether dynamic or static, endurance or resistance. Physical training regimes ought necessarily to be adapted to the specific demands of diagnosis, type and degree of injury and prognosis for individuals who have suffered TBI.

Rehabilitation of Concussion and Post-concussion Syndrome

CONTEXT

Prolonged symptoms after concussion are called post-concussion syndrome (PCS), which is a controversial disorder with a wide differential diagnosis.

EVIDENCE ACQUISITION

MEDLINE and PubMed searches were conducted for the years 1966 to 2011 using the search terms brain concussion/complications OR brain concussion/diagnosis OR brain concussion/therapy AND sports OR athletic injuries. Secondary search terms included post-concussion syndrome, trauma, symptoms, metabolic, sports medicine, cognitive behavioral therapy, treatment and rehabilitation. Additional articles were identified from the bibliographies of recent reviews.

RESULTS

Of 564 studies that fulfilled preliminary search criteria, 119 focused on the diagnosis, pathophysiology, and treatment/rehabilitation of concussion and PCS and formed the basis of this review. Rest is the primary treatment for the acute symptoms of concussion. Ongoing symptoms are either a prolonged version of the concussion pathophysiology or a manifestation of other processes, such as cervical injury, migraine headaches, depression, chronic pain, vestibular dysfunction, visual dysfunction, or some combination of conditions. The pathophysiology of ongoing symptoms from the original concussion injury may reflect multiple causes: anatomic, neurometabolic, and physiologic.

CONCLUSIONS

Treatment approaches depend on the clinician's ability to differentiate among the various conditions associated with PCS. Early education, cognitive behavioral therapy, and aerobic exercise therapy have shown efficacy in certain patients but have limitations of study design. An algorithm is presented to aid clinicians in the evaluation and treatment of concussion and PCS and in the return-to-activity decision.

Return to full functioning after graded exercise assessment and progressive exercise treatment of postconcussion syndrome

Exercise assessment and aerobic exercise training for postconcussion syndrome (PCS) may reduce concussion-related physiological dysfunction and symptoms by restoring autonomic balance and improving cerebral blood flow autoregulation. In a descriptive pilot study of 91 patients referred to a university clinic for treatment of PCS, a subset of 63 patients were contacted by telephone for assessment of symptoms and return to full daily functioning. Those who experienced symptoms during a graded exercise treadmill test (physiologic PCS, n = 40) were compared to those who could exercise to capacity (PCS, n = 23). Both groups had been offered progressive exercise rehabilitation. Overall 41 of 57 (72%) who participated in the exercise rehabilitation program returned to full daily functioning. This included 27 of 35 (77%) from the physiologic PCS group, and 14 of 22 (64%) from the PCS group. Only 1 of the 6 patients who declined exercise rehabilitation returned to full functioning. Interpretation of these results is limited by the descriptive nature of the study, the small sample size, and the relatively few patients who declined exercise treatment. Nonetheless, exercise assessment indicates that approximately one third of those examined did not have physiologic PCS.

Return-to-play decisions

Concussions occur as a result of forces directed to the head or neck, or from impulsive forces transmitted from the body to the head. They result in the rapid onset and spontaneous recovery of short-lived impairment of neurologic function. Concussions represent a functional, rather than structural, disturbance, and do not result in abnormalities on standard structural imaging. This article discusses a comprehensive approach to return to play in sports concussion, including managing athletes returning after prolonged postconcussion syndrome, multiple concussions, and intracranial hematomas and craniotomy.

Return-to-play guidelines in concussion: a closer look at the literature

Traumatic brain injuries that occur during sports have gained significant attention in the literature. Despite improved education and research on proper identification, risk management, and treatment, standardized methods for returning an athlete to play after a concussion are lacking in universal applicability. Current return-to-play guidelines are considered appropriate for the majority of athletes who recover within a few weeks. However, applicability of such guidelines becomes difficult when treating those athletes who experience prolonged symptoms or do not have the resources available to adequately manage complex presentations of concussions. Understanding the guidelines with consideration to special populations will assist the treating physician in providing an appropriate and individualized evaluation and treatment plan to safely return an athlete with a concussion back to play without compromising his or her health.

Reliability of a graded exercise test for assessing recovery from concussion

OBJECTIVE

To evaluate a graded treadmill test for retest reliability (RTR) and interrater reliability (IRR) in the evaluation of the physiologic effects of symptom exacerbation from concussion.

DESIGN

Prospective case series (RTR) and blinded rater assessment of 10 actors portraying patients with and without symptom exacerbation (IRR).

SETTING

University Sports Medicine Concussion Clinic.

PARTICIPANTS

For RTR, 21 refractory concussed patients (11 athletes and 10 nonathletes) and 10 healthy subjects; for IRR, 32 raters representing a variety of health care disciplines.

INTERVENTION

For RTR, a Balke protocol treadmill test to symptom exacerbation before and after 2 to 3 weeks. For IRR, video recordings of actors during the treadmill test viewed by raters blinded to condition.

MAIN OUTCOME MEASURES

For RTR, agreement of the tests for maximal heart rate (HR), systolic blood pressure, diastolic blood pressure, and rating of perceived exertion. For IRR, presence or absence of symptom exacerbation and the symptom exacerbation HR.

RESULTS

Raters achieved a sensitivity of 99% for identifying actors with symptom exacerbation and a specificity of 89% for ruling out concussion symptoms and agreed on 304 of 320 observations (accuracy of 95%). The intraclass correlation coefficient for the symptom exacerbation HR was large at 0.90 (95% confidence interval, 0.78-0.98). The treadmill test had good RTR for maximum HR (intraclass correlation coefficient, 0.79) but not for systolic blood pressure, diastolic blood pressure, or rating of perceived exertion.

CONCLUSIONS

The Balke exercise treadmill protocol has very good IRR and sufficient RTR for identifying patients with symptom exacerbation from concussion.

Cerebrovascular pathophysiology following mild traumatic brain injury

Mild traumatic brain injury (mTBI) or sport-induced concussion has recently become a prominent concern not only in the athletic setting (i.e. sports venue) but also in the general population. The majority of research to date has aimed at understanding the neurological and neuropsychological outcomes of injury as well as return-to-play guidelines. Remaining relatively unexamined has been the pathophysiological aspect of mTBI. Recent technological advances including transcranial Doppler ultrasound and near infrared spectroscopy have allowed researchers to examine the systemic effects of mTBI from rest to exercise, and during both asymptomatic and symptomatic conditions. In this review, we focus on the current research available from both human and experimental (animal) studies surrounding the pathophysiology of mTBI. First, the quest for a unified definition of mTBI, its historical development and implications for future research is discussed. Finally, the impact of mTBI on the control and regulation of cerebral blood flow, cerebrovascular reactivity, cerebral oxygenation and neuroautonomic cardiovascular regulation, all of which may be compromised with mTBI, is discussed.

Physical therapy recommendations for service members with mild traumatic brain injury

Mild traumatic brain injuries (MTBIs) are of increasing concern in both the military and civilian populations as the potential long-term effects and costs of such injuries are being further recognized. Injuries from conflicts in Afghanistan and Iraq have increased public awareness and concern for TBI. The Proponency Office for Rehabilitation and Reintegration, Office of the Surgeon General, US Army tasked a team of physical and occupational therapists to assemble evidence-informed guidelines for assessment and intervention specific to MTBI. Given the paucity of specific guidelines for physical therapy related to MTBI, we focused on literature that dealt with the specific problem area or complaint of the Service member following MTBI. Recommendations, characterized as practice standards or practice options based on strength of evidence, are provided relative to patient/client education, activity intolerance, vestibular dysfunction, high-level balance dysfunction, posttraumatic headache, temporomandibular disorder, attention and dual-task performance deficits, and participation in exercise. While highlighting the need for additional research, this work can be considered a starting point and impetus for the development of evidence-based practice in physical therapy for our deserving Service members.

A preliminary study of subsymptom threshold exercise training for refractory post-concussion syndrome

OBJECTIVE

To evaluate the safety and effectiveness of subsymptom threshold exercise training for the treatment of post-concussion syndrome (PCS).

DESIGN

Prospective case series.

SETTING

University Sports Medicine Concussion Clinic.

PARTICIPANTS

Twelve refractory patients with PCS (6 athletes and 6 nonathletes).

INTERVENTION

Treadmill test to symptom exacerbation threshold (ST) before and after 2 to 3 weeks of baseline. Subjects then exercised 5 to 6 days per week at 80% ST heart rate (HR) until voluntary peak exertion without symptom exacerbation. Treadmill testing was repeated every 3 weeks.

MAIN OUTCOME MEASURES

Adverse reactions to exercise, PCS symptoms, HR, systolic blood pressure (SBP), achievement of maximal exertion, and return to work/sport.

RESULTS

Pretreatment, ST occurred at low exercise HR (147 + or - 27 bpm) and SBP (142 + or - 6 mm Hg). After treatment, subjects exercised longer (9.75 + or - 6.38 minutes to 18.67 + or - 2.53 minutes, P = .001) and achieved peak HR (179 + or - 17 bpm) and SBP (156 + or - 13 mm Hg), both P < .001 versus pretreatment, without symptom exacerbation. Time series analysis showed significant change in rate of symptom reduction for all subjects and reduced mean symptom number in 8/11. Rate of PCS symptom improvement was related to peak exercise HR (r = -0.55, P = .04). Athletes recovered faster than nonathletes (25 + or - 8.7 vs 74.8 + or - 27.2 days, P = .01). No adverse events were reported. Athletes returned to sport and nonathletes to work.

CONCLUSIONS

Treatment with controlled exercise is a safe program that appears to improve PCS symptoms when compared with a no-treatment baseline. A randomized controlled study is warranted.