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No 417: March 28, 2018

Marsh JD, Durkin MW, Hack AE, Markowitz BB, Cheeseman EW. Accuracy of Double Maddox Rod with Induced Hypertropia in Normal Subjects.  Am Orthopt J. 2014;64:76-80. doi: 10.3368/aoj.64.1.76.

BACKGROUND AND PURPOSE: The double Maddox rod is a commonly used instrument to test for cyclotorsion in the clinical setting. This paper assesses the ability of patients without torsional complaint to accurately demonstrate torsional status with varying degrees of induced hypertropia as tested by double Maddox rod.

METHODS: Thirty-seven orthophoric subjects underwent double Maddox rod testing with vertical prism of 3(Δ), 10(Δ), 16(Δ), 20(Δ), and 30(Δ). Subjective torsion was recorded for each prism diopter.

RESULTS: Mean subjective torsion was recorded as 0.95°, 1.6°, 1.9°, 2.1°, and 2.2° for 3(Δ), 10(Δ), 16(Δ), 20(Δ), and 30(Δ), respectively. Torsion increased in a logarithmic manner as modeled by R™ software version 2.15.2.

CONCLUSIONS: The double Maddox rod test as commonly used in clinical practice is both subjective and prone to administrator and subject error. Subjects have more difficulty properly aligning the double Maddox rod as distance between images is increased. It is also possible that recruitment of the oblique muscles during attempted vertical fusion leads to subjective torsion during double Maddox rod testing in otherwise normal participants.

PMID: 25313115

No 416: March 21, 2018

Reinink H, Wegner I, Stegeman I, Grolman W. Rapid systematic review of repeated application of the epley maneuver for treating posterior BPPV. Otolaryngol Head Neck Surg. 2014 Sep;151(3):399-406. doi: 10.1177/0194599814536530. Epub 2014 May 29.

Objective: To evaluate the effect of repeated application of the Epley maneuver on patient-reported symptom relief and resolution of nystagmus in patients with posterior benign paroxysmal positional vertigo (p-BPPV).

Methods: A systematic search was conducted. Studies reporting original study data were included. Relevance and risk of bias (RoB) of the selected articles were assessed. Studies with low relevance, high RoB, or both were excluded. Success percentages and mean values were extracted.

Results: A total of 955 unique studies were retrieved. Fourteen of these satisfied the eligibility criteria. All of the included studies carried a high relevance and a moderate RoB. The majority of studies were 1-armed trials, in which the Epley was repeated only in case previous attempt(s) had failed. The maneuver was not repeated if it was successful. In 32% to 90% of patients, the first treatment session was successful. Reported cumulative success percentages ranged from 40% to 100% after the second session, 67% to 98% after the third session, 87% to 100% after the fourth session, and 100% in the studies in which patients received 5 sessions. One study evaluating the effect of multiple maneuvers in a single session showed a rise in success percentages from 84% for 1 maneuver to 90% after 2 maneuvers and 92% after 3 maneuvers.

Conclusion: Multiple studies with moderate RoB show a beneficial effect of multiple sessions of the Epley maneuver in pBPPV patients who are not fully cleared of symptoms after the first session.

PMID: 24876167

No 415: March 14, 2018

Hunt AW, Paniccia M, Reed N, Keightley M. Concussion-Like Symptoms in Child and Youth Athletes at Baseline: What Is "Typical"? J Athl Train. 2016 Oct;51(10):749-757. doi: 10.4085/1062-6050-51.11.12. Epub 2016 Nov 11.

CONTEXT: After a concussion, guidelines emphasize that an athlete should be asymptomatic before starting a return-to-play protocol. However, many concussion symptoms are nonspecific and may be present in individuals without concussion. Limited evidence exists regarding the presence of "typical" or preinjury (baseline) symptoms in child and youth athletes.

OBJECTIVE: To describe the frequency of symptoms reported at baseline by child and youth athletes and identify how age, sex, history of concussion, and learning factors influence the presence of baseline symptoms.

DESIGN: Cross-sectional cohort study.

SETTING: Baseline testing was conducted at a hospital research laboratory or in a sport or school setting (eg, gym or arena).

PATIENTS OR OTHER PARTICIPANTS: A total of 888 child (9-12 years old, n = 333) and youth (13-17 years old, n = 555) athletes participated (46.4% boys and 53.6% girls, average age = 13.09 ± 1.83 years).

MAIN OUTCOME MEASURE(S): Demographic and symptom data were collected as part of a baseline protocol. Age-appropriate versions of the Post-Concussion Symptom Inventory (a self-report concussion-symptoms measure with strong psychometric properties for pediatric populations) were administered. Demographic data (age, sex, concussion history, learning factors) were also collected.

RESULTS: Common baseline symptoms for children were feeling sleepier than usual (30% boys, 24% girls) and feeling nervous or worried (17% boys, 25% girls). Fatigue was reported by more than half of the youth group (50% boys, 67% girls). Nervousness was reported by 32% of youth girls. Headaches, drowsiness, and difficulty concentrating were each reported by 25% of youth boys and girls. For youths, a higher total symptom score was associated with increasing age and number of previous concussions, although these effects were small (age rs = 0.143, number of concussions rs = .084). No significant relationships were found in the child group.

CONCLUSIONS: Children and youths commonly experienced symptoms at baseline, including fatigue and nervousness. Whether clinicians should expect complete symptom resolution after concussion is not clear.

PMID: 27834505 

Free PMC Article: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5189228/

No 414: March 7, 2018

Newman-Toker DE, Edlow JA. TiTrATE: A Novel, Evidence-Based Approach to Diagnosing Acute Dizziness and Vertigo. Neurol Clin. 2015 Aug;33(3):577-99, viii. doi: 10.1016/j.ncl.2015.04.011.

Diagnosing dizziness can be challenging, and the consequences of missing dangerous causes, such as stroke, can be substantial. Most physicians use a diagnostic paradigm developed more than 40 years ago that focuses on the type of dizziness, but this approach is flawed. This article proposes a new paradigm based on symptom timing, triggers, and targeted bedside eye examinations (TiTrATE). Patients fall into 1 of 4 major syndrome categories, each with its own differential diagnosis and set of targeted examination techniques that help make a specific diagnosis. Following an evidence-based approach could help reduce the frequency of misdiagnosis of serious causes of dizziness. In the spirit of the flipped classroom, the editors of this Neurologic Clinics issue on emergency neuro-otology have assembled a collection of unknown cases to be accessed electronically in multimedia format. By design, cases are not linked with specific articles, to avoid untoward cueing effects for the learner. The cases are real and are meant to demonstrate and reinforce lessons provided in this and subsequent articles. In addition to pertinent elements of medical history, cases include videos of key examination findings.

PMID: 26231273 

Free PMC Article: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4522574/

No 413: February 28, 2018

Riccelli R, Passamonti L, Toschi N, et al. Altered Insular and Occipital Responses to Simulated Vertical Self-Motion in Patients with Persistent Postural-Perceptual Dizziness. Frontiers in Neurology. 2017;8:529. doi:10.3389/fneur.2017.00529

BACKGROUND: Persistent postural-perceptual dizziness (PPPD) is a common functional vestibular disorder characterized by persistent symptoms of non-vertiginous dizziness and unsteadiness that are exacerbated by upright posture, self-motion, and exposure to complex or moving visual stimuli. Recent physiologic and neuroimaging data suggest that greater reliance on visual cues for postural control (as opposed to vestibular cues-a phenomenon termed visual dependence) and dysfunction in central visuo-vestibular networks may be important pathophysiologic mechanisms underlying PPPD. Dysfunctions are thought to involve insular regions that encode recognition of the visual effects of motion in the gravitational field.

METHODS: We tested for altered activity in vestibular and visual cortices during self-motion simulation obtained via a visual virtual-reality rollercoaster stimulation using functional magnetic resonance imaging in 15 patients with PPPD and 15 healthy controls (HCs). We compared between groups differences in brain responses to simulated displacements in vertical vs horizontal directions and correlated the difference in directional responses with dizziness handicap in patients with PPPD.

RESULTS: HCs showed increased activity in the anterior bank of the central insular sulcus during vertical relative to horizontal motion, which was not seen in patients with PPPD. However, for the same comparison, dizziness handicap correlated positively with activity in the visual cortex (V1, V2, and V3) in patients with PPPD.

CONCLUSION: We provide novel insight into the pathophysiologic mechanisms underlying PPPD, including functional alterations in brain processes that affect balance control and reweighting of space-motion inputs to favor visual cues. For patients with PPPD, difficulties using visual data to discern the effects of gravity on self-motion may adversely affect balance control, particularly for individuals who simultaneously rely too heavily on visual stimuli. In addition, increased activity in the visual cortex, which correlated with severity of dizziness handicap, may be a neural correlate of visual dependence.

PMID: 29089920

No 412: February 21, 2018

Söhsten E, Bittar RS, Staab JP. Posturographic profile of patients with persistent postural-perceptual dizziness on the sensory organization test. J Vestib Res. 2016 Jul 2;26(3):319-26. 

BACKGROUND/OBJECTIVE:  Persistent postural-perceptual dizziness (PPPD) was defined by expert consensus for the forthcoming International Classification of Diseases, 11th edition. Its diagnostic criteria were derived from phobic postural vertigo and chronic subjective dizziness. Two key symptoms are postural unsteadiness and visually induced dizziness. We observed that patients with PPPD tended to perform poorly on multiple conditions of the EquiTest® Sensory Organization Test (SOT) and sought to investigate this phenomenon systematically.

METHODS:  We examined cross-sectional, pair-wise group differences in mean scores from SOT conditions 1-6 and composite scores among 20 patients with PPPD, 15 patients recovered from acute vestibular syndromes, and 15 normal individuals (all female, 43 ± 9 years old). We also compared proportions of patients in each group with abnormal sensory analyses, and poor performance across multiple conditions.

RESULTS: Patients with PPPD had significantly lower mean scores than normal individuals on conditions 2-6 and the composite, and lower than recovered patients on conditions 2-3. Recovered patients had significantly lower mean scores than normal individuals on conditions 4-6 and the composite. Patients with PPPD had the greatest likelihood of abnormal sensory analyses.

CONCLUSIONS:  Patients with PPPD had difficulties with postural control across multiple sensory challenges, consistent with postulated neurophysiologic mechanisms of this condition.

PMID: 27392836

No 411: February 14, 2018

Staab JP, Eckhardt-Henn A, Horii A, Jacob R, Strupp M, Brandt T, Bronstein A. Diagnostic criteria for persistent postural-perceptual dizziness (PPPD): Consensus document of the committee for the Classification of Vestibular Disorders of the Bárány Society. J Vestib Res. 2017;27(4):191-208. doi: 10.3233/VES-170622.

This paper presents diagnostic criteria for persistent postural-perceptual dizziness (PPPD) to be included in the International Classification of Vestibular Disorders (ICVD). The term PPPD is new, but the disorder is not. Its diagnostic criteria were derived by expert consensus from an exhaustive review of 30 years of research on phobic postural vertigo, space-motion discomfort, visual vertigo, and chronic subjective dizziness. PPPD manifests with one or more symptoms of dizziness, unsteadiness, or non-spinning vertigo that are present on most days for three months or more and are exacerbated by upright posture, active or passive movement, and exposure to moving or complex visual stimuli. PPPD may be precipitated by conditions that disrupt balance or cause vertigo, unsteadiness, or dizziness, including peripheral or central vestibular disorders, other medical illnesses, or psychological distress. PPPD may be present alone or co-exist with other conditions. Possible subtypes await future identification and validation. The pathophysiologic processes underlying PPPD are not fully known. Emerging research suggests that it may arise from functional changes in postural control mechanisms, multi-sensory information processing, or cortical integration of spatial orientation and threat assessment. Thus, PPPD is classified as a chronic functional vestibular disorder. It is not a structural or psychiatric condition.

PMID: 29036855

No 410: February 7, 2018

Popkirov S, Staab JP, Stone J. Persistent postural-perceptual dizziness (PPPD): a common, characteristic and treatable cause of chronic dizziness. Pract Neurol. 2018 Feb;18(1):5-13. doi: 10.1136/practneurol-2017-001809. Epub 2017 Dec 5.

Persistent postural-perceptual dizziness (PPPD) is a newly defined diagnostic syndrome that unifies key features of chronic subjective dizziness, phobic postural vertigo and related disorders. It describes a common chronic dysfunction of the vestibular system and brain that produces persistent dizziness, non-spinning vertigo and/or unsteadiness. The disorder constitutes a long-term maladaptation to a neuro-otological, medical or psychological event that triggered vestibular symptoms, and is usefully considered within the spectrum of other functional neurological disorders. While diagnostic tests and conventional imaging usually remain negative, patients with PPPD present in a characteristic way that maps on to positive diagnostic criteria. Patients often develop secondary functional gait disorder, anxiety, avoidance behaviour and severe disability. Once recognised, PPPD can be managed with effective communication and tailored treatment strategies, including specialised physical therapy (vestibular rehabilitation), serotonergic medications and cognitive-behavioural therapy.

PMID: 29208729

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