Research: Long-Term Objectives

To develop strategies for reducing the incidence and severity of mild traumatic brain injury (mTBI) in the population that can be translated to clinical practice. This includes continued hypothesis-driven research, development of novel protective equipment, diagnostic equipment for field use and other healthcare settings, neuropharmacological strategies, novel strategies for return to activity and educational tools for disseminating information about mTBI, its evaluation and prevention.

Research Aims

Two Football Helmets Impact
The HIT System™
Neuro Imaging Pic
Clinical Research Protocols

We hypothesize that head acceleration due to impact is predictive of the type and severity of brain injury, and correlated to specific clinical measures of brain injury.


Specific Aims

  1. Develop Head Impact Telemetry System for large-scale recording, storage and retrieval of on-field head impact acceleration data.
    We will improve existing HIT System packaging, sensors, algorithms, data acquisition, power, telemetry, and software analysis tools to make large-scale on-field data collection feasible and cost-effective. The current football helmet system will be expanded to hockey helmets to enable our proposed studies of gender differences in MTBI pathomechanics.

  2. Quantify head acceleration injury tolerances for sustaining MTBI.
    We will collect and analyze data using HIT System in 256 football players (male only) at four institutions and 80 hockey players (40 male/40 female) at 2 institutions over a five-year period. This unique and novel database will permit us to test hypotheses regarding the tolerances for sustaining MTBI and whether gender influences these tolerances.

  3. Correlate head acceleration with clinical variables related to MTBI.
    Using the database created during Aim 2, we will test the hypothesis that increased head acceleration increases short-term measures of brain injury in vivo for concussed players relative to matched controls using validated sideline and clinical tools including standardized sideline assessments, neuropsychological testing, and functional magnetic resonance imaging (fMRI).

The HIT System™

X Ray of HIT System Helmet

Sports provide an Ideal Environment for Monitoring Head Impacts

Real-time monitoring and recording of all significant head impacts using the Head Impact Telemetry (HIT) System™. HIT System™ computes head acceleration, impact duration and impact location for multiple athletes simulatiously to alert team physicians and athletic trainers to potentially injurious impacts.

HIT System Components

Impacts are immediately transmitted (via radio frequence) to a Sideline Controller which records, processes and stores the data.

The Head Impact Telemetry (HIT) System™ monitors, records and processes head impacts in real-time during all practices and competitions. The HIT System™ measures impact magnitude, location and duration.

The HIT System™ is the first and only commercially available system that can measure head accelerations (impacts) in real-time during games and practices. The HIT System™ sensor/encoder package contains impact sensors, a processor, and a transmitter. (A commercial version of this product for football use will be available from Riddell this fall.)

The HIT System™ transforms a helmet or headgear into a head-impact monitor. A microprocessor-based data collector receives impact data continuously from encoders that can be hundreds of meters away. The HIT System™ can monitor dozens of athletes or soldiers simultaneously. Our proprietary software analyzes those data and sends a warning via an alert pager if any impact has a potentially injurious profile.

HIT System Software

Multiple athletes can be monitored simultaneously.

The data collector stores all of the key signatures of each impact — peak linear acceleration, rotational acceleration, impact duration and location, etc. — with a time stamp for future analysis. The data can be accessed to compute commonly used head-impact severity measures (HIC, GSI, etc.).

The HIT System™ reflects more than a decade of research (supported in part by the National Center for Medical Rehabilitation Research at the National Institutes of Health).

HITS has been tested in the crucible of NFL, college and high school football stadiums and practice fields since 2004. Using the HIT System, we have recorded over two million impacts and corresponding data on head injuries.

Hit System Outcomes - Football - Over 2 millions hits

Simbex and our research partners are using the analysis of these data to shed new light on the biomechanical causes of mild traumatic brain injuries (mTBI). This research may lead to advancements in protective equipment or other injury reduction strategies.

 

U.S. Patent 6,826,509 & other patents pending

Clinical Research Protocols

MRI Brain Image

Combining current concussion management strategies with emerging technology to diagnose, treat and evaluate concussive impacts in athletes. Clinical assessments include: symptomatology, neurocognitive function, brain imaging (fMRI/DTI) and postural stability.

Neurocognitive Assessment:

ImPACT© Website
ImPACT Website

ImPACT© - Computerized Neuropsychological Exam:

ImPACT© (Immediate Post-concussion Assessment and Cognitive Test) is a computerized neuropsychological test battery specifically designed and validated for use as a tool for sports-related concussion that takes approximately 20 minutes to complete[1]. ImPACT consists of six cognitive test modules, including tests for verbal memory, visual working memory, attention, visual attention span, processing speed, and choice reaction time. Composite scores are computed for memory, reaction time, and processing speed, and postconcussion symptom data selected from 22 commonly described symptoms (based on the consensus from the 1st International Conference on Concussion in Sports, Vienna 2001 - used by NFL and NHL). ImPACT is administered at one preseason baseline time point and serially at three post-concussion time points: within 24-48 hours post-injury, and 7 days or symptom resolution.

MRI Brain Image

Neuropsychological Test Battery

Participants undergo approximately 2.5 hours of neuropsychological (NP) testing. The tests were chosen to probe cognitive domains showing particular deficits in mTBI. Tests with alternate forms were chosen where available, to allow for repeat measures with minimal practice effect contamination, although this should be minimized given the 12 month interval between assessments. The battery assesses levels of estimated general intellectual function (Wide Range Achievement Test - 3rd Edition (WRAT-3 Green)), verbal learning and memory (California Verbal Learning Test II, CVLT II versions Standard, Alternate, and Research and Word Memory Test), visual memory (Brief Visiospatial Memory Test- Revised (BVMT-R)), reaction time and distractibility (Continuous Performance Task (CPT)), motor function and coordination,and psychomotor speed (Wechsler Adult Intelligence Scale, Digit Symbol Coding subtests and D-KEFS Trail Making subtests). In addition, a group of tests assessing working memory, executive function (Stroop, Controlled Oral Word Fluency Test (D-KEFS CFL/FAS) and Controlled Oral Word Categories (D-KEFS Animal/Boys and Clothing/Girls)) and attentional function (Paced Auditory Serial Additional Test, WAIS-III Letter Number Sequencing, ) are given.

Functional Magnetic Resonance Imaging (fMRI)

Subjects undergo a structural scan sequence and 4 fMRI memory tasks: visual and verbal continuous recognition memory tasks (encoding and retrieval, with long and short delay memory), verbal and visual-spatial 3-back (Working Memory, vigilance, reaction time). The Dartmouth Advanced Neuroimaging Research Center, opened in December 2005, runs a research-dedicated Philips Acheiva 3.0T MR scanner, allowing us to run the proposed protocol at high field on this latest generation scanner.

Diffusion Tensor Imaging (DTI)Brain Imaging

Diffusion Tensor Imaging (DTI) measures the diffusivity of water in a number of orientations. Its usefulness is based on the observation that water diffusivity is high along an axon's body and very low perpendicular to it -- axons function like long tubes, in other words — and that the observed values will vary with structural changes, such as axonal tearing or swelling. In practice, DTI measurements reflect the combined diffusions of tens of thousands of axons (and other tissues too) at each "voxel", or three dimensional sample region. The "diffusion tensor", a mathematical model of the diffusion, gives the best estimate of overall voxel diffusion behavior under the assumption that it can be modeled with a single diffusion ellipsoid. From diffusion tensors, images can be created of average or maximal diffusivity measurements, or of more complicated values such as the "fractional anisotropy" (FA), which is the degree to which diffusion ellipsoids exhibit isotropy (uniform diffusion in all directions) or anisotropy (diffusion limited to a particular direction).

BESS ProtocolBESS Protocol

Postural Stability and Balance Assessment
Balance Error Scoring System (BESS)

The Balance Error Scoring System (BESS) provides a portable, cost-effective and objective method of assessing static postural stability. The BESS test can be used to assess the effects of mild head injury on static postural stability both on- and off-field. Information obtained from this clinical balance tool can be used to assist clinicians in making return to play decisions following a mild head injury.

Force Plate

Force plate testing is conducted using an AccuSway Force Platform from AMTI. This test utilizes the same test protocol as the BESS test, running 3 trials on "firm ground" on the flat force plate, and the 3 "foam pad" trials with the Airex balance pad centered on the Force Plate. Testing is run using the AMTI Balance Clinic software program. Additional Force Plate testing with a military ISOBalance Force Plate is also being conducted for comparison.

On-Field Concussion Assessment
Sport Concussion Assessment Tool 2 (SCAT2)

The Sport Concussion Assessment Tool, Version 2 (SCAT2) was developed by the 2008 International Conference on Concussion in Sport. This tool was developed to assist medical and field personnel in evaluating an athlete for a concussion or head injury. The SCAT2 combines symptom evaluation, cognitive assessment techniques (Maddocks Score and Standard Assessment of Concussion (SAC)) and balance and coordination examinations. It provides a useful tool for initial assessment, advice and return-to-play decisions for coaches, athletic trainers and team physicians.