Neurosensory Disorders in Mild Traumatic Brain Injury

Michael E. Hoffer, Carey D. Balaban

• Publisher: Academic Press
• Year: 2018
• Print ISBN: 9780128123447
• eBook ISBN: 9780128125489
• Topic: Biological Sciences
• Subtopic: Neurology
• Index: Biological Sciences

Mild traumatic Brain Injury (mTBI or Concussion) is an increasingly common public health issue in sports, military environments, and life in today's active world. Despite a great deal of study and public attention to this disorder, knowledge about optimal diagnostic, prognostic, and treatment information remains lacking. Neurosensory symptoms have been shown to be the most frequent complications of mTBI in both the acute and chronic setting. Neurosensory Disorders in Mild Traumatic Brain Injury brings together both the basic science work as well as the clinical work in mTBI into one volume to provide a comprehensive examination of the neurosensory issues associated with this disorder. Coverage includes chapters on defining mild Traumatic Brain Injury, neurosensory consequences, neurosensory disorders in clinical practice, and diagnosis and treatment for neurosensory disorders in mTBI. This book is written for clinicians, researchers, residents and students in neurology and neuroscience.- Provides a comprehensive examination of the neurosensory issues associated with mild Traumatic Brain Injury and concussion- Brings together both the basic science work and the clinical work in mTBI into a single volume- Helps clinicians understand the best diagnosis and treatment paths and puts current research into perspective for researchers

Section IV

Diagnosis and Treatment

Outline

• Chapter 16 Diagnostic Approaches Techniques in Concussion/Mild Traumatic Brain Injury
• Chapter 17 Neurosensory Diagnostic Techniques for Mild Traumatic Brain Injury
• Chapter 18 Perfusion and Susceptibility Weighted Imaging in Traumatic Brain Injury
• Chapter 19 Current Treatment Modalities for mTBI
• Chapter 20 Vestibular Rehabilitation for Mild Traumatic Brain Injury (mTBI)
• Chapter 21 Cognitive Rehabilitation for Mild Traumatic Brain Injury (mTBI)
• Chapter 22 Emerging Technologies for Diagnosing Mild Traumatic Brain Injury
• Chapter 23 Emerging Treatment Modalities
• Chapter 24 mTBI/Concussion

Chapter 16

Diagnostic Approaches Techniques in Concussion/Mild Traumatic Brain Injury

Where are we?

Rebecca Smith, Mariya Chepisheva, Thomas Cronin, PhD and Barry M. Seemungal, Department of Medicine, Imperial College, London, United Kingdom

Abstract

Currently, sporting body consensus criteria consider concussion to be a mild traumatic brain injury (mTBI), which is indicated by a transient mental obtundation. Acute concussion diagnosis, thus, relies upon first-hand observation of the impact and the effect upon the patient (or recorded video), and clinical assessment including clinical history and examination. The diagnosis of a concussion can be difficult if there are no witnesses. Additionally, the inability of the patient to provide a clear account of the circumstances of the injury can make the diagnostic process more challenging, and on the other hand, is suggestive of a retrospective amnesia and, hence, supportive of a concussion. However, the converse may not be true, since some patients may provide a clear history of no concussion, but display objective signs of momentary mental obtundation, not recalled by the patient. Thus, since a concussion diagnosis by patient history is problematic, diagnosis should rely upon objective measures, including third-person witness account, clinical examination, and laboratory testing. We review the different means to make a diagnosis of concussion.

Keywords

Mild traumatic brain injury; concussion; cognition; diagnosis; biomarker; neurophysiology

Chapter Introduction

Currently, sporting body consensus criteria consider concussion to be a mild traumatic brain injury (mTBI), which is indicated by a transient mental obtundation.¹ Acute concussion diagnosis, thus, relies upon first-hand observation of the impact and the effect upon the patient (or recorded video), and clinical assessment including clinical history and examination. The diagnosis of a concussion can be difficult if there are no witnesses. Additionally, the inability of the patient to provide a clear account of the circumstances of the injury can make the diagnostic process more challenging, and on the other hand, is suggestive of a retrospective amnesia and, hence, supportive of a concussion. However, the converse may not be true, since some patients may provide a clear history of no concussion, but display objective signs of momentary mental obtundation, not recalled by the patient. Thus, since a concussion diagnosis by patient history is problematic, diagnosis should rely upon objective measures, including third-person witness account, clinical examination, and laboratory testing. We review the different means to make a diagnosis of concussion.

The Clinical Approach

Clinical testing is a vital tool in establishing new or ongoing impairments secondary to concussion. There are a plethora of bedside diagnostic techniques, some of which require little or no equipment and can provide helpful clues detail regarding potential areas of injury.^2,3

How Important is a Subjective History?

Typically, diagnosis in related fields of neurology and neuro-otology rely heavily upon a detailed subjective history to define symptoms and, hence, explore differential diagnoses. Particular attention is given to the frequency, nature and severity of symptoms. However, in acute concussion, paying close attention to symptoms may confuse the clinician. For example, the patient may not complain of symptoms such as imbalance or dizziness, yet objectively may score poorly on clinical vestibular or balance tests. It is, therefore, important that clinicians do not rely solely on patients’ subjective complaints. Asking family members or carers separately may help to corroborate any functional deficits.

Subjective Measures: “Symptom Scales”

To provide further detail on the severity and impact of symptoms, patient reported outcome measures (PROMs) can evaluate the impact of impairments on physical and mental health, and patients’ ability to carry out activities of daily living. PROMs evaluating specific impairments such as imbalance or dizziness, may include for example, the Activities-specific Balance Confidence Scale (ABC) or Dizziness handicap inventory (DHI), while those evaluating function or the ability to carry out activities of daily living include the Functional Independence Measure (FIM) or Disability Rating Scale (DRS). It is important to consider the psychometric properties of the measure as well as more practical factors including time to administer and ease of use.

More holistic patient reported outcomes include those evaluating quality of life (QOL) or health-related quality of life (HRQOL). Such measures can be useful in monitoring recovery or progress with rehabilitation. Measures of QOL or HRQOL specific to the TBI population include Quality of Life after Brain Injury (QOLIBRI), the European Brain Injury Questionnaire (EBIQ), and the TBI quality of life measurement system (TBI-QOL). Despite relative rigorous evaluation of the psychometric properties of each measure,^4,5 there appears to be no current consensus regarding the most appropriate tool to use. Although a systematic review indicated further work is required to establish the most relevant measure for this population, the authors did recommend the use of a TBI specific measure such as the QOLIBRI in conjunction with a more robust tool such as the Short Form 36 (SF-36).⁶

Bedside Clinical (Objective) Tests

Eye Movement Examination

A physical eye movement examination is a critical tool in the assessment of mTBI patients. It serves to evaluate and highlight peripheral and/or central injuries and, thus, acts as an important diagnostic tool.⁷ Essential components of the eye movement examination include the cover test, which is performed to ascertain failure of binocular gaze mechanisms including any skew deviation, and gaze assessment for nystagmus in primary and lateral gaze. Smooth pursuit, vergence and extra ocular range of movement can then also be evaluated. Deficits noted in smooth pursuit indicate abnormal brain function ipsilesionally, that is, in the direction of the pursuit deficit, but localizes poorly since lesions from the cerebellum to the cortex can produce impaired smooth pursuit.^8,9 Saccadic hypo- or hypermetria and/or latency should be examined during vertical and horizontal saccades and indicate central dysfunction. Increased latency and/or error rates with antisaccades indicate frontal cortical deficits.

Bedside Vestibular Ocular Reflex Testing

A proportion of patients with acute TBI will display signs of temporal bone transection with injury to the vestibular (and auditory) system; however, this level of injury is not usually found in acute concussion/mTBI, unless a chronic case was misclassified.¹⁰ Hence, it is always sensible to routinely evaluate the vestibular ocular reflex (VOR) using the head thrust test, a high acceleration but low amplitude single jerk movement of the head in a horizontal plane. The patient is instructed to keep their gaze fixed on the clinician. A refixation saccade back to the focus point (lost because of the deficient VOR) indicates a positive result. This test shows high sensitivity in detecting VOR deficits.^11,12 The video head impulse test (vHIT) is able to quantify any high frequency VOR dysfunction. A head mounted camera and inertial sensors simultaneously collect data on head and eye motion, and hence can provide a VOR slow-phase velocity gain with respect to the head motion. Evidence demonstrates high specificity and sensitivity of the vHIT,^13,14 while additional benefits include the ability to measure covert saccades (eye movements not observable to the clinician) and short testing times.¹⁵

Benign Paroxysmal Positional Vertigo

BBPV is common in acute TBI, causing dizziness, imbalance, and falls, especially in older adults. Posttraumatic benign paroxysmal positional vertigo (BPPV) is thought to be due to mechanical displacement of the otoconia caused by the head trauma itself. Current evidence from retrospective and nonacute cases extrapolate a BPPV incidence in acute TBI patients of 10%–28%^16–18; however, our experience in acute TBI (patients admitted to a major trauma unit with a moderate-severe brain injury) shows a true BPPV incidence of nearer 50%. TBI patients also appear to have a propensity for more complex variants of the condition, that is, those with multi canal BPPV, requiring multiple treatment sessions with h...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• Dedication
• List of Contributors
• About the Editors
• Section I: Defining Mild TBI
• Section II: Overview of Neurosensory Consequences
• Section III: Neurosensory Disorders in Clinical Practice
• Section IV: Diagnosis and Treatment
• Index