The Centers for Disease Control and Prevention (CDC) estimated that about 2.87 million TBI-related emergency department (ED) visits, hospitalizations, and deaths occurred in 2014.47 The current estimates of the sports-related concussions and brain injuries in the US are 1.6–3.8 million every year.48 The annual percent change was reported by Rao et al as 9.6 (95% CI 8.2– 11.0) for all ages, 10.3 (95% CI 2.5–18.1) for youth and 9.7 (95% CI 9.4–10.0) for adults between 2005 and 2014, which showed an increased incidence of TBIs in Canada. According to the same study, the proportion of Canadians who reported having a TBI in 2014 more than doubled to 3.2%, compared to 1.4% in 2005. There were approximately 155,000 TBI cases in 2014 in Canada.49
Patients with a mTBI do not show any evidence of intracranial pathologies such as bleeding, subdural or epidural hematoma and/or cranial fracture on standard imaging.50 Recent studies have shown that mTBI can cause functional neuronal disruption and structural damage in humans and animals. Due to a cerebral energy imbalance, these disruptions have the potential to manifest a wide clinical spectrum, ranging from subtle cognitive deficits only detectable on neuropsychological testing to overt neurological and behavioral symptoms.14,51
Although full recovery is expected within three months after concussion/mTBI, there has been a small group of concussion sufferers that have experienced persistent symptoms. A number of factors can influence the rate of recovery, including the mechanism and setting for the initial injury, age, and recurrent concussion incidents in the past. A typical mTBI patient at the Meditech Rehabilitation Centre would have had a concussion three or more months prior to initial presentation, and had already consulted a barrage of healthcare practitioners, including their family physicians, a neurologist, a physiotherapist and others, with no relief in their symptoms. All 35 patients noted improvement in their cognitive functions after PBMT.
PBMT has often been used ‘off label’ as a treatment modality for post-concussion symptoms secondary to TBI. Although most PBMT devices are generally classified and licensed as general wellness devices without public health oversight, Meditech Rehabilitation Centre uses the BIOFLEX® DUO+ system, which has Health Canada and FDA cleared treatment indications for soft tissue injuries, minor pains and to increase local blood flow. Meditech Rehabilitation Centre has been treating patients for specific post-concussive symptoms like neck pain and stiffness for several years as a supporting regimen to traditional therapies. At Meditech Rehabilitation Centre, a number of patients have reported improvement in concussion symptoms using our BIOFLEX® DUO+ devices after traditional treatment methods proved less successful.
The Biphasic Dose Response
A major concern in the acceptance of PBMT for the treatment of neurological conditions is the use of appropriate and effective dosage. In many cases, especially in our own clinical observations, it has been found in PBMT that more light is not necessarily therapeutically better than less light in terms of energy delivery. This “biphasic dose responses (also called Arndt-Schulz law or hormesis)” shows that PBMT can simultaneously inhibit and stimulate, and the techniques and settings for consistently achieving these effects have not always been clearly stated.52 Because of this, certain studies that utilize a static dosing mechanism in PBMT for the treatment of neurological conditions either mention no effect, or on occasion, certain uncomfortable side effects such as headaches. Being cognizant of the biphasic dose response so typical in PBMT, treatment in Meditech Rehabilitation Centre is provided in a gradually increasing dosing fashion, first starting with a relatively mild dose with continuous light application before gradually increasing the energy density application (in Joules/cm2) and adding pulse modulation in weekly intervals. Despite the parameters used in this study, in clinical practice the patient’s response and their capacity to follow-up were taken into consideration. This gradual dosing pattern allows tissues to adjust to the treatment and absorb more photons of light as treatment progresses while maintaining depth penetration.53
Of note, in this study, was the dual treatment modality, in which both the cervical area and parts of the cranium were treated. Most studies that have used PBMT for the treatment of neurological conditions tended to focus treatment only in the cranial area.26,27,31,32,35,54-56 The inclusion of the cervical area treatment has demonstrated that PBMT can cause vasodilation and increased local circulation and can have a potential effect on certain neurotransmitters like serotonin (5-HT) and cholinesterase levels.57 Although most studies show that at most cranial penetration of most PBMT devices are minimal (up to 4 cm at most, based on cadaver studies),58 including cervical treatments has been instrumental in cognitive improvement due to the effect of increased cerebral circulation.59
The ImPACT® test with PBMT
The ImPACT® test included six tests/modules (i.e., word discrimination, design memory, x’s and o’s, symbol match, color match, three letters) that yielded five composite/domain scores (i.e., verbal memory, visual memory, visual motor skills, reaction time, and impulse control). For the verbal memory, visual memory, visual-motor skills, and reaction time composite scores, demographically adjusted percentile scores (i.e., age and sex) were provided on the standard clinical report printout. Demographically adjusted percentile scores for the impulse control composite score were computed from the normative data tables available from the test publisher.46The BIOFLEX® DUO+ PBMT intervention was effective in improving patients’ scores for several of the ImPACT® test categories including: Color Match, Verbal Composite Score, Visual Composite Score and Visual Motor Speed and Reaction Time.
The Cognitive Efficiency Index (CEI) is a measure tabulated from the Symbol Match section of the ImPACT® test. It was calculated based on the speed and accuracy of items clicked correctly. This was just one metric; however, it should not be considered an overall concussion severity index nor has it been validated for that purpose. The ImPACT® test has removed the CEI in its newest streamlined version 4 format released in 2021 and has replaced it with the Two Factor score46. However, given the significance of this measure at the 95% confidence level, we have decided to still include the CEI in the results as a report of its utility.
The CDC divides mTBI symptoms into 4 categories: Thinking/Remembering, Sleep, Emotional/Mood, and Physical.60 Aside from the objective and rapid measurement of cognitive abilities, ImPACT® included a subjective symptom reporting scale. The ImPACT post-concussion symptom rating scale contained 22 somatic, affective, and cognitive symptoms, with each symptom being rated from 0 (none) to 6 (severe). Two values can be computed for the symptom questionnaire: total symptom score (sum of all ratings for all symptoms) and the number of symptoms endorsed as being present (regardless of the severity). Both of these values were examined for this study. The patients’ symptoms decreased significantly at the 95% confidence level, for patients after receiving PBMT with the BIOFLEX® DUO+ system. The Wilcoxon Signed Rank tests detailed the decrease in the total symptom score. Thus, patients were experiencing less symptoms after the intervention than without it.
Improvement in the objective and subjective scores of the ImPACT® test after treatment with PBMT showed that computer-based neurocognitive assessments can be considered a valuable aid in diagnosis and assessment of treatment response for mTBI patients with persistent post-concussive symptoms.
LIMITATIONS:
There were limitations to this study. Specifically, the sample size was small, and the treatment time was limited to one month. In clinical practice, further improvement was noted beyond the one month period, and some patients had decided to continue treatment at home utilizing portable devices. Given that the consistency of use of portable devices cannot be controlled for, we decided not to include these in our study. Increasing sample sizes, extending the treatment period, and including cerebral blood flow measurement could potentially provide additional evidence of cognitive improvement utilizing PBMT.
RECOMMENDATIONS:
Our group did not initiate an ImPACT® baseline examination for this population given that they have already suffered an injury prior to their first presentation. Doing a baseline ImPACT® test measurement under controlled conditions may have provided a better assessment of a person’s cognitive state pre-concussion and a better comparison of improvement with the Post Injury 1 and 2 tests. Initiating a study with the baseline measurements for certain concussion-prone population groups, i.e., hockey players, members of the armed forces, construction workers, may prove to be a valid option for a future study.