Traumatic Brain Injury: Sport Concussion Research Lab Traumatic Brain Injury: Basic Mechanisms and Implications for Survivors of Intimate Partner Violence Dr. Paul van Donkelaar School of Health and Exercise Sciences University of British Columbia - Okanagan

Definition of Concussion Sport Concussion Research Lab Definition of Concussion A type of mild traumatic brain injury (mTBI) induced by biomechanical forces that result in complex pathophysiological processes within the brain.

Symptoms of Concussion Sport Concussion Research Lab Symptoms of Concussion Confusion - not sure of time/place Cognitive deficits - difficulty making decisions Attentional deficits - difficulty filtering out irrelevant stimuli Sensorimotor deficits - dizziness, balance and gait problems

Anatomical Evidence of Concussion – Structural Imaging Sport Concussion Research Lab Anatomical Evidence of Concussion – Structural Imaging Stroke Multiple Sclerosis Concussion

Brain Activation in Concussion – Working Memory Sport Concussion Research Lab Brain Activation in Concussion – Working Memory

Objective Assessment of Concussion Sport Concussion Research Lab Objective Assessment of Concussion Need to develop objective tools to assess deficits post-concussion. If these assessment tools can be translated into clinical use, then initial diagnosis, management, and return-to-play decisions can be improved. Focus on behavioural, structural, and physiological biomarkers in humans.

Balance/Gait Deficits in Concussion Sport Concussion Research Lab Balance/Gait Deficits in Concussion

Neurocognitive Deficits in Concussion – Task Switching Sport Concussion Research Lab Neurocognitive Deficits in Concussion – Task Switching

Structural effects of concussion Sport Concussion Research Lab Structural effects of concussion Myelin water imaging (UBCV) – uses T2 decay signal to probe integrity of myelin.

Cerebral Blood Flow and Concussion Symptoms Sport Concussion Research Lab Cerebral Blood Flow and Concussion Symptoms

Cerebral Blood Pressure-Flow Relationship and Concussion History Sport Concussion Research Lab Cerebral Blood Pressure-Flow Relationship and Concussion History Ability of the local cerebrovasculature to buffer slow changes in arterial blood pressure in order to maintain the delivery of cerebral blood flow = cerebral autoregulation

Cerebral Blood Pressure-Flow Relationship and Concussion History Sport Concussion Research Lab Cerebral Blood Pressure-Flow Relationship and Concussion History Blood Pressure Cerebral Blood Velocity

Cerebral Blood Pressure-Flow Relationship and Concussion History Sport Concussion Research Lab Cerebral Blood Pressure-Flow Relationship and Concussion History The FAST changes in arterial blood pressure associated with the cardiac cycle are passed through to the cerebrovasculature relatively unimpeded Blood Pressure Cerebral Blood Velocity Spontaneous Data

Cerebral Blood Pressure-Flow Relationship and Concussion History Sport Concussion Research Lab Cerebral Blood Pressure-Flow Relationship and Concussion History The SLOWER changes in arterial blood pressure associated with sympathetic activity (10 second cycles) are buffered by the cerebrovasculature Blood Pressure Cerebral Blood Velocity Spontaneous Data 0.10 Hz

Cerebral Blood Pressure-Flow Relationship and Concussion History Sport Concussion Research Lab Cerebral Blood Pressure-Flow Relationship and Concussion History The EVEN SLOWER changes in arterial blood pressure associated with myogenic tone (20 second cycles) are buffered to an even greater extent Blood Pressure Cerebral Blood Velocity Spontaneous Data 0.10 Hz 0.05 Hz

Cerebral Blood Pressure-Flow Relationship and Concussion History Sport Concussion Research Lab Cerebral Blood Pressure-Flow Relationship and Concussion History 28 elite football players (aged 18-22) 17 had no previous history of diagnosed concussions 11 had 3+ previous diagnosed concussions Squat-stand maneuvers at two frequencies (0.05 and 0.10 Hz) Phase (Timing Buffer) and Gain (Amplitude Buffer) of the cerebral pressure-flow relationship were assessed at: 0.05 Hz (indicative of the influence of myogenic tone) 0.10 Hz (indicative of the influence of sympathetic tone)

Cerebral Blood Pressure-Flow Relationship and Concussion History Sport Concussion Research Lab Cerebral Blood Pressure-Flow Relationship and Concussion History MCA Phase (radians) Pressure-flow dynamics are more pressure-passive during very low frequency oscillations Repeated head impacts affect the intrinsic myogenic tone of the cerebrovasculature MCA

Compare contact and non-contact sport athletes pre- vs. post-season Sport Concussion Research Lab Cerebral Blood Pressure-Flow Relationship across a season of contact sport Wright et al.,, JAMA Neurol., under 1st revision Squat-stand protocol; measure cerebral blood flow and blood pressure; head impacts Compare contact and non-contact sport athletes pre- vs. post-season Repetitive subconcussive head trauma from a season of contact sport induces exposure-dependent impairments in sympathetically-mediated cerebrovascular autoregulation

Blood Biomarkers of Concussion Sport Concussion Research Lab Blood Biomarkers of Concussion

Blood biomarkers across a season of contact sport Sport Concussion Research Lab Blood biomarkers across a season of contact sport Neurofilament light concentration measured Compare contact and non-contact sport athletes pre- vs. post-season Repetitive subconcussive head trauma from a season of contact sport induces increases in biomarker for CNS axonal damage

Chronic Traumatic Encephalopathy Sport Concussion Research Lab Chronic Traumatic Encephalopathy Progressive neurodegenerative disease. Develops as a result of repetitive mild traumatic brain injury. Clinical characteristics: chronic cognitive, behavioural, mood, and motor symptoms. Neuropathological characteristics: accumulation of hyperphosphorylated tau in neurons and astrocytes.

Chronic Traumatic Encephalopathy - Neuropathology Sport Concussion Research Lab Chronic Traumatic Encephalopathy - Neuropathology Alzhiemer’s CTE Diffuse distribution Depths of sulci No perivascular clustering Perivascular clustering Present at layers III-VI Present at layers II-III

Chronic Traumatic Encephalopathy – Athletes vs. Military Sport Concussion Research Lab Chronic Traumatic Encephalopathy – Athletes vs. Military 18 yo athlete: football player; repetitive concussive injuries 21 yo athlete: football player; repetitive subconcussive injuries 34yo veteran: 2 blast exposures 1 and 6 years before 45yo veteran: 1 blast 2 years before

Characterizing concussion in intimate partner violence Sport Concussion Research Lab Characterizing concussion in intimate partner violence Intimate partner violence (IPV) leads to a variety of negative mental health outcomes. Quite often IPV involves physical assault targeting the head/brain. Thus, it is possible the mental health challenges associated with IPV are due in part to TBI. Unfortunately, the potential interaction between TBI and IPV has rarely been studied.

Sport Concussion Research Lab The current evidence Brain injury severity due to IPV negatively associated with measures of memory, learning, and cognitive flexibility.

Sport Concussion Research Lab The current evidence Brain injury severity due to IPV negatively associated with intrinsic functional connectivity in network implicated in cognitive deficits in TBI populations.

Potential Significance Sport Concussion Research Lab Potential Significance Uncommon for staff at women’s shelters to screen for TBI. Suggests that TBI is not taken into account in services provided to clients at women’s shelters. This may contribute to challenges facing survivors of IPV. Clearly and objectively characterizing the impact of TBI in IPV could serve to change policies and funding for community organizations providing support for this population.

The long-term consequences of concussion are currently not well known. Sport Concussion Research Lab Summary/Conclusions Concussion is much more prevalent than most people suspect in both contact sport and intimate partner violence settings. Newer objective measures/techniques may lead to better diagnosis and management of concussion. The long-term consequences of concussion are currently not well known. In IPV settings, the development of better screening procedures may lead to provision of better support services for survivors.

Collaborators Funding Sport Concussion Research Lab Cheryl Wellington Henrik Zetterberg Li-Shan Chou Phil Ainslie Peter Cripton Karen Mason University of Oregon UBCO UBCV UBCV University of Gothenburg Kelowna Women’s Shelter Funding