REVIEW URRENT C OPINION
Mild traumatic brain injury: neurosensory effects Michael E. Hoffer
Purpose of review The purpose of this review is to examine recent advances in the diagnosis and treatment of mild traumatic brain injury with attention to the neurosensory sequelae. Recent findings There has been a great deal of work done in this area over the last 18 months. Much of the work focuses on diagnosing the disorder. The neurosensory sequelae can be difficult to diagnose with headache relying on subjective information and cognitive effects and fatigue being very difficult to accurately measure. Dizziness is a very common disorder and probably the easiest effect to measure objectively and evidence is mounting that diagnosing and treating dizziness is very important in this patient group. Advances in treatment have occurred in the last 18 months but there is still a great deal of work necessary in this area. There is one reported pharmaceutical countermeasure and it is vital that this medicine be further tested and developed. Therapies remain the mainstay of treatment and work in this area needs to be supported. Summary It is clear from this review that mild traumatic brain injury is a rapidly growing public health issue and it vital for those who see these patients to be well versed in the neurosensory manifestations so that appropriate diagnosis and treatment are provided and accurate prognostic implications can be provided for patients and their families. Keywords dizziness, mild traumatic brain injury, neurosensory sequelae, vestibular rehabilitation
INTRODUCTION Mild traumatic brain injury (mTBI) is an increasingly common public health concern that has been receiving increased attention in both the lay press and medical literature. This review will highlight recent work on this important medical disorder. Because the goal of this article is to highlight already published work and to serve as a ready resource for the readership, the review will be organized into sections as follows: epidemiology, symptoms, diagnosis, and treatment. This article will confine its focus to mTBI. Although there are many definitions for mTBI in the articles that will be reviewed, in general, this condition is defined as a head impact or blast exposure, followed by a period of alteration or loss of consciousness, and then associated with sequelae that are usually neurosensory in type (dizziness, headache, cognitive disturbances, hearing loss, tinnitus, and/or sleep disorders). mTBI is often associated with other comorbid conditions such as posttraumatic stress disorder. Because the literature on the topics of comorbid conditions is, at times, difficult to interpret, this will not be a main topic of this review. It should be pointed out that the most comprehensive published material on this subject www.co-neurology.com
can be found on the Centers for Disease Control and Prevention website [1 ]. This site examines all aspects of traumatic brain injury (TBI) and mTBIrelated issues. &&
EPIDEMIOLOGY The epidemiology of mTBI is often difficult to interpret. Many cases go unreported and in cases that do present to an emergency room or walk in clinic, classifications differ or other minor injuries get more attention. In an excellent letter to JAMA, Marin et al. [2 ] from Harvard’s School of Public Health examined trends of visits to emergency departments (ED) for TBI. This group examined data from 950 hospitals and found a sharp increase in the weighted rates of ED visits from 2006 to 2010. In 2006, there &&
Department of Otolaryngology, Miller School of Medicine, University of Miami, Miami, Florida, USA Correspondence to Michael E. Hoffer, Department of Otolaryngology, University of Miami, 120 NW 14th St, Miami, FL 33136, USA. Tel: +1 305 243 1484; e-mail: [email protected] Curr Opin Neurol 2015, 28:74–77 DOI:10.1097/WCO.0000000000000164 Volume 28 Number 1 February 2015
Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.
Mild traumatic brain injury: neurosensory effects Hoffer
KEY POINTS The most common acute, subacute, and chronic disabilities seen after mTBI are neurosensory. Dizziness and headaches are the most common disorder seen after mTBI. Specialized balance tests may be the best way to diagnose mTBI. A new pharmaceutical countermeasure has been described and should be tested in additional population. Despite advances in the area of mTBI, more work in the area of diagnosis and treatment continue to be necessary.
were 637 TBI visits per 100 000 ED visits and by 2010 this figure was up to 822 per 100 000. The majority of this increase was due to an increase in the number of mTBI or concussions. The CDC agreed with these numbers and found that almost 75% of all TBI visits were in individuals in the 0–4 or over 65-year-old population [1 ]. This is likely a slight overestimate of these age group incidences with respect to mTBI because mTBI is common in sports and often does not result in ED visits. So there may be more individuals between the ages 4 and 65 who do not report their injury. In examining trends in TBI, Lagbas et al. [3] found that older (>75-year old) men were at the highest risk with falls being the primary mode of injury. Falls were also the most frequent cause of TBI in those under 4. Motor vehicle accidents were most common in the 15–24-year old population but in many cases this mechanism of injury causes more moderate and severe head trauma. A great deal of epidemiologic work has been focused on special groups. In particular, the lay press has focused on football injuries [4]. Perhaps the best incidence data on mTBI alone comes from the military. Many of the seminal articles in this area pre-date the time period for this review; however, a number of recent articles discuss the fact that nearly 20% of all individuals who deployed had some symptoms of mTBI [5 ,6 ,7]. &&
&
&
SYMPTOMS The primary symptoms of mTBI are neurosensory in origin [5 ,6 ]. Dizziness has been reported to be the most common symptom of mTBI in a number of articles published earlier than this review. Headache closely follows dizziness in frequency. Cognitive disorders, sleep disorders, and hearing disorders &
&
(hearing loss, tinnitus, and central auditory process¨ ller et al. [8] ing disorders) complete the list. Mo characterized the cognitive disorders as a cognitive fatigability that can be seen in other neurological disorders. This cognitive disorder could be determined by a standard series of cognitive tests. Losoi et al. [9] demonstrated that this fatigue extended beyond just cognitive issues when he examined 87 mTBI patients against a control population of orthopedic patients. This laboratory found that insomnia, pain, and depressive symptoms were correlated with fatigue. In a French study of over 500 mTBI patients, Laborey et al. [10 ] confirmed that the neurosensory symptoms could persist for several months and added blurred vision and personality changes to the list. This same group was one of many groups to argue that these neurosensory mTBI symptoms are not specific to mTBI and can be found in other neurological disorders or in posttraumatic stress disorders [11,12]. As mentioned earlier, focusing on all the elements of this debate is well beyond the scope of this review. Lastly, it is important to note that there is mounting evidence that long-term neurodegenerative changes that resemble other neurodegenerative diseases may be associated with mTBI [13]. Again, specific evidence for this contention goes beyond the scope of this review. &&
DIAGNOSIS Diagnosis of mTBI has always presented challenges. This is true because many of the symptoms are selfreported and can vary in intensity over time. Much of the seminal work for infield diagnostics was done before the period of this review and even those tools continue to be of questionable validity. One of the most promising areas is in examining eye movements. Cifu et al. [14 ] utilized a head-mounted tracker attached to binocular cameras to track eye movement in response to visual or motion stimuli. In 60 individuals with chronic mTBI, this group found position and velocity error as well as saccadic intrusions. These findings are promising and are in keeping with findings from an ongoing study in our laboratory. Magnetoencephalography (MEG) is a technique that has been studied for TBI diagnosis. In 2014, Lee et al. [15 ] examined a large series of patients and found an 87% specificity for using MEG for mTBI. One of the most interesting studies in this time period involved the use of a Delphi method for surveying eye specialists. A Delphi process involves iterative expert surveys. Utilizing this method, a group of Veteran’s Administration investigators was able to develop a 17-question vision tool that was designed to work in concert with seven specific eye tests [16 ]. There has been an advance in imaging
1350-7540 Copyright ß 2015 Wolters Kluwer Health, Inc. All rights reserved.
&&
&&
&
www.co-neurology.com
Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.
75
Neuro-ophthalmology and neuro-otology
technology. Eierud et al. [17] performed a metaanalysis of functional MRI (fMRI) techniques. This analysis showed a frontal and prefrontal vulnerability in fMRI studies of mTBI. This analysis does a superb job summarizing a great number of fMRI studies but detailed analysis of these studies goes beyond the scope of this review. There also has been an increased emphasis on ED and even point of injury diagnostic test. One very recent publication compared the King Devicktest with the Sports Concussion Assessment Tool 2 in a group of 26 individuals with concussion with 33 controls. The Sports Concussion Assessment Tool 2 and symptoms scale were highly significant but the King Devicktest test failed to show a difference between the two groups in this patient subset [18]. In a similar ED experiment, Zuckerbraun et al. [19] describe the Acute Concussion Evaluation tool for use in the pediatric ED population after mTBI. They found that the Acute Concussion Evaluation tool implementation improved follow-up and adherence to instructions in comparing over 150 patients preimplementation to postimplementation.
TREATMENT Advances in treatment for mTBI have always been slow. In previous reporting periods, there were a host of treatments reported and none of these methods had universal success. The most significant change in this stalemate was the work by Hoffer et al. [20 ] that for the first time showed that a pharmacologic treatment, N-acetyl-cysteine, was an effective countermeasure for blast-induced mTBI. Working in a combat environment, this group conducted a double-blind, placebo-controlled experiment and demonstrated that NAC was far more effective than control medicine at 7-day symptom reduction. Other pharmacologic methods are in development but none have gone to clinical studies as of yet. The mainstay of treatment remains therapy. Nelson Sheese and Hammeke [21] recently published a review of successful therapies for treatment of mTBI. Whereas this study advocated the benefits of therapy, a large systematic review of the literature revealed that more studies need to be done to demonstrate positive effects of therapy [22]. To that end, there has been some recent work looking at specific training types. Oculomotor training is designed to reduce the ocular errors seen in mTBI patients. Thiagarajan et al. [23] employed oculomotor therapy on 12 individuals with mTBI and significantly corrected ocular errors in the whole group. Cervical physical therapy was examined by Schneider et al. [24] who showed an 8-week symptoms resolution rate in 73% of 15 mTBI patients &&
76
www.co-neurology.com
versus 7% in the controls. There is a significant volume of literature examining traditional vestibular rehabilitation, but most of it pre-dates the period of this review. One more recent study conducted by Alsalaheen et al. [25 ] examined the most prescribed and effective exercises. This group examined 104 patients and found that head and eye exercises as well as postural exercises were the most effective for treatment. &&
CONCLUSION mTBI is an increasingly common public health issue. Many of the subacute and chronic symptoms are neurosensory in nature. In this review, we have cast a slightly broader net and examined a variety of the most recent work looking at mTBI including its epidemiology, diagnosis, and treatment. As the goal of the review was to focus on neurosensory issues, we have emphasized high-value publications that focus on those areas. As there have been hundreds of articles published in this field over the last 18–24 months, we have had to confine our review. There are certainly many valuable contributions that have not been reviewed here or that fall just before the prescribed evaluation time points. Acknowledgements None. Financial support and sponsorship None. Conflicts of interest There are no conflicts of interest.
REFERENCES AND RECOMMENDED READING Papers of particular interest, published within the annual period of review, have been highlighted as: & of special interest && of outstanding interest 1. http://www.cdc.gov/TraumaticBrainInjury/index.html. &&
The Centers for Disease Control and Prevention’s definitive TBI resource. 2. Marin JR, Weaver MD, Yealy DM, Mannix RC. Trends in visits for traumatic && brain injury to emergency departments in the United States. JAMA 2014; 311:1917–1919. This is one of the best epidemiologic articles available. 3. Lagbas C, Bazargan-Hejazi S, Shaheen M, et al. Traumatic brain injury related hospitalization and mortality in California. Biomed Res Int 2013; 2013:143092. 4. Olson D, Sikka RS, Labounty A, Christensen T. Injuries in professional football: current concepts. Curr Sports Med Rep 2013; 12:381–390. 5. Shah A, Ayala M, Capra G, et al. Otologic assessment of blast and nonblast & injury in returning middle east-deployed service members. Laryngoscope 2014; 124:272–277. This is an excellent review of the neurosensory sequela of mTBI. 6. Johnson CM, Perez CF, Hoffer ME. The implications of physical injury on & otovestibular and cognitive symptomatology following blast exposure. Otolaryngol Head Neck Surg 2014; 150:437–440. This is an examination of the impact of other injuries with mTBI. 7. Bryan CJ. Multiple traumatic brain injury and concussive symptoms among deployed military personnel. Brain Inj 2013; 27:1333–1337.
Volume 28 Number 1 February 2015
Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.
Mild traumatic brain injury: neurosensory effects Hoffer 8. Mo¨ller MC, Nygren de Boussard C, Oldenburg C, Bartfai A. An investigation of attention, executive, and psychomotor aspects of cognitive fatigability. J Clin Exp Neuropsychol 2014; 36:1–14. 9. Losoi H, Wa¨ljas M, Turunen S, et al. Resilience is associated with fatigue after mild traumatic brain injury. J Head Trauma Rehabil 2014. [Epub ahead of print] 10. Laborey M, Masson F, Ribe´reau-Gayon R, et al. Specificity of postconcussion && symptoms at 3 months after mild traumatic brain injury: results from a comparative cohort study. J Head Trauma Rehabil 2014; 29:E28–E36. This is an excellent larger study of post TBI outcomes. 11. Lagarde E, Salmi LR, Holm LW, et al. Association of symptoms following mild traumatic brain injury with posttraumatic stress disorder vs postconcussion syndrome. JAMA Psychiatry 2014; 71:1032–1040. 12. Waldron-Perrine B, Hennrick H, Spencer RJ, et al. Postconcussive symptom report in polytrauma: influence of mild traumatic brain injury and psychiatric distress. Mil Med 2014; 179:856–864. 13. Fakhran S, Alhilali L. Neurodegenerative changes after mild traumatic brain injury. Prog Neurol Surg 2014; 28:234–242. 14. Cifu DX, Wares JR, Hoke KW, et al. Differential eye movements in mild traumatic && brain injury versus normal controls. J Head Trauma Rehabil 2014. [Epub ahead of print] Superb analysis of eye movement issues from specialized VA group focusing on TBI. 15. Lee RR, Huang M. Magnetoencephalography in the diagnosis of concussion. && Prog Neurol Surg 2014; 28:94–111. This is an excellent review of MEG. 16. Goodrich GL, Martinsen GL, Flyg HM, et al., US Department of Veterans Affairs. & Development of a mild traumatic brain injury-specific vision screening protocol: a Delphi study. J Rehabil Res Dev 2013; 50:757–768. 17. Eierud C, Craddock RC, Fletcher S, et al. Neuroimaging after mild traumatic brain injury: review and meta-analysis. Neuroimage Clin 2014; 4:283–294. doi:10.1016/j.nicl.2013.12.009.
18. Silverberg ND, Luoto TM, Ohman J, Iverson GL. Assessment of mild traumatic brain injury with the King-Devick Test1 in an emergency department sample. Brain Inj 2014; 28:1590–1593. doi: 10.3109/02699052.943287. 19. Zuckerbraun NS, Atabaki S, Collins MW, et al. Use of modified acute concussion evaluation tools in the emergency department. Pediatrics 2014; 133:635–642. 20. Hoffer ME, Balaban C, Slade MD, et al. Amelioration of acute sequelae of blast && induced mild traumatic brain injury by N-acetyl cysteine: a double-blind placebo controlled study. PLoS One 2013; 8:e54163. This is the first and only known pharmaceutical countermeasure available to reduce the sequel of mTBI that can be given after the injury. 21. Nelson Sheese AL, Hammeke TA. Rehabilitation from postconcussion syndrome: nonpharmacological treatment. Prog Neurol Surg 2014; 28:149– 160. 22. Nygren-de Boussard C, Holm LW, Cancelliere C, et al. Nonsurgical interventions after mild traumatic brain injury: a systematic review. Results of the International Collaboration on Mild Traumatic Brain Injury Prognosis. Arch Phys Med Rehabil 2014; 95 (Suppl 3):S257–S264. 23. Thiagarajan P, Ciuffreda KJ. Versional eye tracking in mild traumatic brain injury (mTBI): effects of oculomotor training (OMT). Brain Inj 2014; 28:930– 943. 24. Schneider KJ, Meeuwisse WH, Nettel-Aguirre A, et al. Cervicovestibular rehabilitation in sport-related concussion: a randomised controlled trial. Br J Sports Med 2014; 48:1294–1298. 25. Alsalaheen BA1, Whitney SL, Mucha A, et al. Exercise prescription patterns in && patients treated with vestibular rehabilitation after concussion. Physiother Res Int 2013; 18:100–108. doi: 10.1002/pri.1532. This is an excellent examination of rehabilitation.
1350-7540 Copyright ß 2015 Wolters Kluwer Health, Inc. All rights reserved.
www.co-neurology.com
Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.
77
Mild traumatic brain injury: neurosensory effects Michael E. Hoffer
Purpose of review The purpose of this review is to examine recent advances in the diagnosis and treatment of mild traumatic brain injury with attention to the neurosensory sequelae. Recent findings There has been a great deal of work done in this area over the last 18 months. Much of the work focuses on diagnosing the disorder. The neurosensory sequelae can be difficult to diagnose with headache relying on subjective information and cognitive effects and fatigue being very difficult to accurately measure. Dizziness is a very common disorder and probably the easiest effect to measure objectively and evidence is mounting that diagnosing and treating dizziness is very important in this patient group. Advances in treatment have occurred in the last 18 months but there is still a great deal of work necessary in this area. There is one reported pharmaceutical countermeasure and it is vital that this medicine be further tested and developed. Therapies remain the mainstay of treatment and work in this area needs to be supported. Summary It is clear from this review that mild traumatic brain injury is a rapidly growing public health issue and it vital for those who see these patients to be well versed in the neurosensory manifestations so that appropriate diagnosis and treatment are provided and accurate prognostic implications can be provided for patients and their families. Keywords dizziness, mild traumatic brain injury, neurosensory sequelae, vestibular rehabilitation
INTRODUCTION Mild traumatic brain injury (mTBI) is an increasingly common public health concern that has been receiving increased attention in both the lay press and medical literature. This review will highlight recent work on this important medical disorder. Because the goal of this article is to highlight already published work and to serve as a ready resource for the readership, the review will be organized into sections as follows: epidemiology, symptoms, diagnosis, and treatment. This article will confine its focus to mTBI. Although there are many definitions for mTBI in the articles that will be reviewed, in general, this condition is defined as a head impact or blast exposure, followed by a period of alteration or loss of consciousness, and then associated with sequelae that are usually neurosensory in type (dizziness, headache, cognitive disturbances, hearing loss, tinnitus, and/or sleep disorders). mTBI is often associated with other comorbid conditions such as posttraumatic stress disorder. Because the literature on the topics of comorbid conditions is, at times, difficult to interpret, this will not be a main topic of this review. It should be pointed out that the most comprehensive published material on this subject www.co-neurology.com
can be found on the Centers for Disease Control and Prevention website [1 ]. This site examines all aspects of traumatic brain injury (TBI) and mTBIrelated issues. &&
EPIDEMIOLOGY The epidemiology of mTBI is often difficult to interpret. Many cases go unreported and in cases that do present to an emergency room or walk in clinic, classifications differ or other minor injuries get more attention. In an excellent letter to JAMA, Marin et al. [2 ] from Harvard’s School of Public Health examined trends of visits to emergency departments (ED) for TBI. This group examined data from 950 hospitals and found a sharp increase in the weighted rates of ED visits from 2006 to 2010. In 2006, there &&
Department of Otolaryngology, Miller School of Medicine, University of Miami, Miami, Florida, USA Correspondence to Michael E. Hoffer, Department of Otolaryngology, University of Miami, 120 NW 14th St, Miami, FL 33136, USA. Tel: +1 305 243 1484; e-mail: [email protected] Curr Opin Neurol 2015, 28:74–77 DOI:10.1097/WCO.0000000000000164 Volume 28 Number 1 February 2015
Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.
Mild traumatic brain injury: neurosensory effects Hoffer
KEY POINTS The most common acute, subacute, and chronic disabilities seen after mTBI are neurosensory. Dizziness and headaches are the most common disorder seen after mTBI. Specialized balance tests may be the best way to diagnose mTBI. A new pharmaceutical countermeasure has been described and should be tested in additional population. Despite advances in the area of mTBI, more work in the area of diagnosis and treatment continue to be necessary.
were 637 TBI visits per 100 000 ED visits and by 2010 this figure was up to 822 per 100 000. The majority of this increase was due to an increase in the number of mTBI or concussions. The CDC agreed with these numbers and found that almost 75% of all TBI visits were in individuals in the 0–4 or over 65-year-old population [1 ]. This is likely a slight overestimate of these age group incidences with respect to mTBI because mTBI is common in sports and often does not result in ED visits. So there may be more individuals between the ages 4 and 65 who do not report their injury. In examining trends in TBI, Lagbas et al. [3] found that older (>75-year old) men were at the highest risk with falls being the primary mode of injury. Falls were also the most frequent cause of TBI in those under 4. Motor vehicle accidents were most common in the 15–24-year old population but in many cases this mechanism of injury causes more moderate and severe head trauma. A great deal of epidemiologic work has been focused on special groups. In particular, the lay press has focused on football injuries [4]. Perhaps the best incidence data on mTBI alone comes from the military. Many of the seminal articles in this area pre-date the time period for this review; however, a number of recent articles discuss the fact that nearly 20% of all individuals who deployed had some symptoms of mTBI [5 ,6 ,7]. &&
&
&
SYMPTOMS The primary symptoms of mTBI are neurosensory in origin [5 ,6 ]. Dizziness has been reported to be the most common symptom of mTBI in a number of articles published earlier than this review. Headache closely follows dizziness in frequency. Cognitive disorders, sleep disorders, and hearing disorders &
&
(hearing loss, tinnitus, and central auditory process¨ ller et al. [8] ing disorders) complete the list. Mo characterized the cognitive disorders as a cognitive fatigability that can be seen in other neurological disorders. This cognitive disorder could be determined by a standard series of cognitive tests. Losoi et al. [9] demonstrated that this fatigue extended beyond just cognitive issues when he examined 87 mTBI patients against a control population of orthopedic patients. This laboratory found that insomnia, pain, and depressive symptoms were correlated with fatigue. In a French study of over 500 mTBI patients, Laborey et al. [10 ] confirmed that the neurosensory symptoms could persist for several months and added blurred vision and personality changes to the list. This same group was one of many groups to argue that these neurosensory mTBI symptoms are not specific to mTBI and can be found in other neurological disorders or in posttraumatic stress disorders [11,12]. As mentioned earlier, focusing on all the elements of this debate is well beyond the scope of this review. Lastly, it is important to note that there is mounting evidence that long-term neurodegenerative changes that resemble other neurodegenerative diseases may be associated with mTBI [13]. Again, specific evidence for this contention goes beyond the scope of this review. &&
DIAGNOSIS Diagnosis of mTBI has always presented challenges. This is true because many of the symptoms are selfreported and can vary in intensity over time. Much of the seminal work for infield diagnostics was done before the period of this review and even those tools continue to be of questionable validity. One of the most promising areas is in examining eye movements. Cifu et al. [14 ] utilized a head-mounted tracker attached to binocular cameras to track eye movement in response to visual or motion stimuli. In 60 individuals with chronic mTBI, this group found position and velocity error as well as saccadic intrusions. These findings are promising and are in keeping with findings from an ongoing study in our laboratory. Magnetoencephalography (MEG) is a technique that has been studied for TBI diagnosis. In 2014, Lee et al. [15 ] examined a large series of patients and found an 87% specificity for using MEG for mTBI. One of the most interesting studies in this time period involved the use of a Delphi method for surveying eye specialists. A Delphi process involves iterative expert surveys. Utilizing this method, a group of Veteran’s Administration investigators was able to develop a 17-question vision tool that was designed to work in concert with seven specific eye tests [16 ]. There has been an advance in imaging
1350-7540 Copyright ß 2015 Wolters Kluwer Health, Inc. All rights reserved.
&&
&&
&
www.co-neurology.com
Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.
75
Neuro-ophthalmology and neuro-otology
technology. Eierud et al. [17] performed a metaanalysis of functional MRI (fMRI) techniques. This analysis showed a frontal and prefrontal vulnerability in fMRI studies of mTBI. This analysis does a superb job summarizing a great number of fMRI studies but detailed analysis of these studies goes beyond the scope of this review. There also has been an increased emphasis on ED and even point of injury diagnostic test. One very recent publication compared the King Devicktest with the Sports Concussion Assessment Tool 2 in a group of 26 individuals with concussion with 33 controls. The Sports Concussion Assessment Tool 2 and symptoms scale were highly significant but the King Devicktest test failed to show a difference between the two groups in this patient subset [18]. In a similar ED experiment, Zuckerbraun et al. [19] describe the Acute Concussion Evaluation tool for use in the pediatric ED population after mTBI. They found that the Acute Concussion Evaluation tool implementation improved follow-up and adherence to instructions in comparing over 150 patients preimplementation to postimplementation.
TREATMENT Advances in treatment for mTBI have always been slow. In previous reporting periods, there were a host of treatments reported and none of these methods had universal success. The most significant change in this stalemate was the work by Hoffer et al. [20 ] that for the first time showed that a pharmacologic treatment, N-acetyl-cysteine, was an effective countermeasure for blast-induced mTBI. Working in a combat environment, this group conducted a double-blind, placebo-controlled experiment and demonstrated that NAC was far more effective than control medicine at 7-day symptom reduction. Other pharmacologic methods are in development but none have gone to clinical studies as of yet. The mainstay of treatment remains therapy. Nelson Sheese and Hammeke [21] recently published a review of successful therapies for treatment of mTBI. Whereas this study advocated the benefits of therapy, a large systematic review of the literature revealed that more studies need to be done to demonstrate positive effects of therapy [22]. To that end, there has been some recent work looking at specific training types. Oculomotor training is designed to reduce the ocular errors seen in mTBI patients. Thiagarajan et al. [23] employed oculomotor therapy on 12 individuals with mTBI and significantly corrected ocular errors in the whole group. Cervical physical therapy was examined by Schneider et al. [24] who showed an 8-week symptoms resolution rate in 73% of 15 mTBI patients &&
76
www.co-neurology.com
versus 7% in the controls. There is a significant volume of literature examining traditional vestibular rehabilitation, but most of it pre-dates the period of this review. One more recent study conducted by Alsalaheen et al. [25 ] examined the most prescribed and effective exercises. This group examined 104 patients and found that head and eye exercises as well as postural exercises were the most effective for treatment. &&
CONCLUSION mTBI is an increasingly common public health issue. Many of the subacute and chronic symptoms are neurosensory in nature. In this review, we have cast a slightly broader net and examined a variety of the most recent work looking at mTBI including its epidemiology, diagnosis, and treatment. As the goal of the review was to focus on neurosensory issues, we have emphasized high-value publications that focus on those areas. As there have been hundreds of articles published in this field over the last 18–24 months, we have had to confine our review. There are certainly many valuable contributions that have not been reviewed here or that fall just before the prescribed evaluation time points. Acknowledgements None. Financial support and sponsorship None. Conflicts of interest There are no conflicts of interest.
REFERENCES AND RECOMMENDED READING Papers of particular interest, published within the annual period of review, have been highlighted as: & of special interest && of outstanding interest 1. http://www.cdc.gov/TraumaticBrainInjury/index.html. &&
The Centers for Disease Control and Prevention’s definitive TBI resource. 2. Marin JR, Weaver MD, Yealy DM, Mannix RC. Trends in visits for traumatic && brain injury to emergency departments in the United States. JAMA 2014; 311:1917–1919. This is one of the best epidemiologic articles available. 3. Lagbas C, Bazargan-Hejazi S, Shaheen M, et al. Traumatic brain injury related hospitalization and mortality in California. Biomed Res Int 2013; 2013:143092. 4. Olson D, Sikka RS, Labounty A, Christensen T. Injuries in professional football: current concepts. Curr Sports Med Rep 2013; 12:381–390. 5. Shah A, Ayala M, Capra G, et al. Otologic assessment of blast and nonblast & injury in returning middle east-deployed service members. Laryngoscope 2014; 124:272–277. This is an excellent review of the neurosensory sequela of mTBI. 6. Johnson CM, Perez CF, Hoffer ME. The implications of physical injury on & otovestibular and cognitive symptomatology following blast exposure. Otolaryngol Head Neck Surg 2014; 150:437–440. This is an examination of the impact of other injuries with mTBI. 7. Bryan CJ. Multiple traumatic brain injury and concussive symptoms among deployed military personnel. Brain Inj 2013; 27:1333–1337.
Volume 28 Number 1 February 2015
Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.
Mild traumatic brain injury: neurosensory effects Hoffer 8. Mo¨ller MC, Nygren de Boussard C, Oldenburg C, Bartfai A. An investigation of attention, executive, and psychomotor aspects of cognitive fatigability. J Clin Exp Neuropsychol 2014; 36:1–14. 9. Losoi H, Wa¨ljas M, Turunen S, et al. Resilience is associated with fatigue after mild traumatic brain injury. J Head Trauma Rehabil 2014. [Epub ahead of print] 10. Laborey M, Masson F, Ribe´reau-Gayon R, et al. Specificity of postconcussion && symptoms at 3 months after mild traumatic brain injury: results from a comparative cohort study. J Head Trauma Rehabil 2014; 29:E28–E36. This is an excellent larger study of post TBI outcomes. 11. Lagarde E, Salmi LR, Holm LW, et al. Association of symptoms following mild traumatic brain injury with posttraumatic stress disorder vs postconcussion syndrome. JAMA Psychiatry 2014; 71:1032–1040. 12. Waldron-Perrine B, Hennrick H, Spencer RJ, et al. Postconcussive symptom report in polytrauma: influence of mild traumatic brain injury and psychiatric distress. Mil Med 2014; 179:856–864. 13. Fakhran S, Alhilali L. Neurodegenerative changes after mild traumatic brain injury. Prog Neurol Surg 2014; 28:234–242. 14. Cifu DX, Wares JR, Hoke KW, et al. Differential eye movements in mild traumatic && brain injury versus normal controls. J Head Trauma Rehabil 2014. [Epub ahead of print] Superb analysis of eye movement issues from specialized VA group focusing on TBI. 15. Lee RR, Huang M. Magnetoencephalography in the diagnosis of concussion. && Prog Neurol Surg 2014; 28:94–111. This is an excellent review of MEG. 16. Goodrich GL, Martinsen GL, Flyg HM, et al., US Department of Veterans Affairs. & Development of a mild traumatic brain injury-specific vision screening protocol: a Delphi study. J Rehabil Res Dev 2013; 50:757–768. 17. Eierud C, Craddock RC, Fletcher S, et al. Neuroimaging after mild traumatic brain injury: review and meta-analysis. Neuroimage Clin 2014; 4:283–294. doi:10.1016/j.nicl.2013.12.009.
18. Silverberg ND, Luoto TM, Ohman J, Iverson GL. Assessment of mild traumatic brain injury with the King-Devick Test1 in an emergency department sample. Brain Inj 2014; 28:1590–1593. doi: 10.3109/02699052.943287. 19. Zuckerbraun NS, Atabaki S, Collins MW, et al. Use of modified acute concussion evaluation tools in the emergency department. Pediatrics 2014; 133:635–642. 20. Hoffer ME, Balaban C, Slade MD, et al. Amelioration of acute sequelae of blast && induced mild traumatic brain injury by N-acetyl cysteine: a double-blind placebo controlled study. PLoS One 2013; 8:e54163. This is the first and only known pharmaceutical countermeasure available to reduce the sequel of mTBI that can be given after the injury. 21. Nelson Sheese AL, Hammeke TA. Rehabilitation from postconcussion syndrome: nonpharmacological treatment. Prog Neurol Surg 2014; 28:149– 160. 22. Nygren-de Boussard C, Holm LW, Cancelliere C, et al. Nonsurgical interventions after mild traumatic brain injury: a systematic review. Results of the International Collaboration on Mild Traumatic Brain Injury Prognosis. Arch Phys Med Rehabil 2014; 95 (Suppl 3):S257–S264. 23. Thiagarajan P, Ciuffreda KJ. Versional eye tracking in mild traumatic brain injury (mTBI): effects of oculomotor training (OMT). Brain Inj 2014; 28:930– 943. 24. Schneider KJ, Meeuwisse WH, Nettel-Aguirre A, et al. Cervicovestibular rehabilitation in sport-related concussion: a randomised controlled trial. Br J Sports Med 2014; 48:1294–1298. 25. Alsalaheen BA1, Whitney SL, Mucha A, et al. Exercise prescription patterns in && patients treated with vestibular rehabilitation after concussion. Physiother Res Int 2013; 18:100–108. doi: 10.1002/pri.1532. This is an excellent examination of rehabilitation.
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