Rodney Taylor, Doctor of Audiology, Advanced Studies in Tinnitus and Hyperacusis, Certified by the American Institute of Balance for Concussion and Vestibular Rehabilitation.
Our sense of equilibrium comes from the brain receiving, and accurately interpreting, information from vision, proprioception and the vestibular system. The vestibular system includes the vestibular labyrinth in the inner ear, which senses our head movement/ position, the vestibular nerve from the ear to the brain, and the vestibular connections within the brain.
Vestibular disorders can come from pathologies in any area of this complex system. They can be insidious or due to factors such as trauma (motor vehicle accidents, falls, contact sports, blows to the head), infections, aging, medications, brain-related problems, or secondary to other diseases or injuries. Symptoms can include dizziness, imbalance, blurry vision, motion sensitivity, nausea, poor concentration, muscle guarding/restrictionof movement, decreased activity levels or social interaction, anxiety and depression. Our Posturography System analyzes the three sensory inputs of balance (vision, proprioception and vestibular system) with the Sensory organization test. It evaluates complete and objective postural diagnoses for comparison with normative data. It also allows for customizable stimulations and innovative analysis.
Debacker et al., 2018, have estimated that more than 50% of the brain’s circuits involve vision and eye control. There are several systems that should be investigated in individuals with brain injuries that result in balance issues. These include the evaluation of the vestibulo-ocular reflex, the integration of visual and vestibular inputs, oculomotor testing, the evaluation of convergence and divergence and measures that require a verbal response from the patient. Researchers have investigated cortical activation patters in response to visual motion stimulation such as optokinetic stimulation and normal functioning individuals show distinct patters of cortical activations and deactivations that are reciprocal and simultaneious (Becker-Bense et al., 2012; Brandt et al., 1998; Deutschlander et al., 2008; Dieterich et al., 2003; Kikuchi et al., 2009; Kleinschmidt et al., 2002; and Rommer et al.,, 2015). Areas of cortical activation include the bilateral medial parieto-occipital visual areas, intraparietal culcus and the striate and extrastriate visual cortex. Cortical deactivations include the posterior insula, parieto-insular multisensory vestibular cortices, posterior region of superior temporal gyrus, inferior parietal lobule, anterior cingulate gyrus, hippocampus, and the corpus callosum.
Often, the vestibular system is involved and outcomes for recovery are often prolonged when vestibular dysfunction is involved. It is common for head injuries to result in Benign Paroxsymal Postitional Vertigo and this is easily diagnosed through patient history. Provoking symptomology can be done by placing the patient in different positions with different head alignments and performing canalith repositioning. This procedure is routinely done in individuals who present with the symptomology associated with specific complaints and the treatment is done immediately with the Semont maneuver or the Gans Repositioning Maneuver.
Vestibular rehabilitation is a well-documented, exercise-based rehabilitation strategy designed to promote central compensation for vestibular dysfunction. These measures can be customized to accommodate the patients’ unique needs and goals and is implemented on and individual basis. The protocols include elements of both in-clinic and home-based exercise therapy. 20 to 50% of individuals that do not experience significant improvements with conventional vestibular rehabilitation may not improve due to a failure to adequately address symptoms of visual motion sensitivity (Rossi-Izquierdo et al., 2011, Pavlou et al., 2013). It is my protocol to address these issues initially with a neuro optometrist, who is part of my team. They are equipped with exercises to reduce susceptibility to disorientation and autonomic symptoms, use optokinetic stimulation, and serve to reduce visual over reliance, especially as it relates to perceptual and postural responses. Neuro optometrists deal with binocular vision (the ability to use two eyes together as a coordinated team to see a single three-dimensional image of surroundings), convergence (the eyes work together to create a single fused image of near objects by simultaneous adduction of both eyes) and convergence insufficiency. The prevalence in concussion is between 47 to 64% (brahm et al., 2009; Capo-Aponte et al., 2012; Debacker et al., 2018). If diplopia develops or one eye turns outward 7 cm from the patient’s nose, this is a sign of convergence issues (Debacker et al., 2018). Saccades are abnormal in 30% of patients and smooth pursuit is abnormal in 60% of patients that suffer from head injury.
Rodney Taylor, Doctor of Audiology, Post-Doctoral Specialty Certificate in Tinnitus and Hyperacusis, Certified by the American Institute of Balance for Concussion and Vestibular Rehabilitation