Inaccurate Saccades and Enhanced Vestibulo-Ocular Reflex Suppression during Combined Eye-Head Movements in Patients with Chronic Neck Pain: Possible Implications for Cervical Vertigo

A New Suppression Index Calculation Using the Visually Enhanced Vestibulo-Ocular Reflex and Vestibulo-Ocular Reflex Suppression Paradigms in the Video Head Impulse Test

The aim of this study is to calculate the gains of the quantified visually enhanced vestibulo-ocular reflex (qVVOR) and the quantified vestibulo-ocular reflex suppression (qVORS), using a specific system to generate a visual suppression index (SI) in healthy subjects obtained through the gains of qVVOR and qVORS, and to determine the normal values of the index, as well as the influence of age and sex variables on the SI.

METHODS

This prospective observational clinical study includes 83 healthy subjects who underwent the head impulse and suppression tests (HIMP and SHIMP, respectively), qVVOR, and qVORS tests, all of the vHIT. The sinusoidal tests (qVVOR and qVORS) were conducted at an intended frequency of 0.75 Hz. The gains of these tests were calculated using a system specifically designed for this purpose. A formula for the SI was established using a ratio of the gains from these tests. Two SI values are presented: unilateral, distinct for each direction of head movement, and bilateral, representing the suppression of both sides simultaneously.

RESULTS

Mean gains for the qVVORs were 0.981 ± 0.070 and 0.978 ± 0.077 for the rightwards and leftwards qVVORs, respectively. The gains for the suppressed tests were 0.334 ± 0.112 and 0.353 ± 0.110 for the rightwards and leftwards qVORSs, respectively. A difference of 0.05 Hz was observed between the expected (0.75 Hz) and the obtained frequency of head movement, which is statistically significant (p < 0.001). The SI was 0.342 ± 0.118 for the right side (right SI) and 0.363 ± 0.117 for the left side (left SI). The bilateral SI had a mean value of 0.295 ± 0.104. No significant differences in the SI were noted according to the subject's age. The SI for women was lower than in the case of males.

CONCLUSIONS

The VVOR/VORS quantification algorithm allows for the reliable calculation of the numerical gain of qVVOR and qVORS with mathematical soundness and consistency of results. Our data support the use of a single or specific measure for direction of head movement; although significant differences exist, these differences are not clinically relevant.

Academic performance and musculoskeletal pain in adolescents with uncorrected vision problems

BACKGROUND

Undetected vision problems are common in school children, and a prevalence of up to 40% has previously been reported. Uncorrected vision and lack of optimal eye wear can have a significant impact on almost all aspects of everyday life, such as development and learning, academic performance, pain and discomfort, and quality of life. This study aimed to analyze the relationship between uncorrected vision problems, educational outcomes, and musculoskeletal pain symptoms.

METHODS

A total of 152 school children (15.1 ± 0.8 years, mean ± SD; 40% males) were included in the study. All participants were recruited from a free-of-charge school vision testing program in Kathmandu, Nepal. Academic grades were collected from the school records of the participants' nationwide final grade examinations. A questionnaire was used to record the use of digital devices, screen time, and associated symptoms, including musculoskeletal pain (Wong-Baker FACES Pain Rating Scales).

RESULTS

A total of 61 children (40%) had uncorrected vision, with a cycloplegic refraction of SER - 0.53 ± 0.52 (mean ± SD). Children with uncorrected vision had significantly more third division grades (26 vs. 9%, p = 0.004) and shoulder pain in general/during screen use (66 vs. 43/40%, p = 0.008/0.003; 2.1/1.9 vs. 1.1/1.0 mean pain score, p = 0.002/0.001) compared with children with normal vision. Sex based subanalyses showed that only girls with uncorrected vision had more third division grades (25 vs. 4%, p = 0.006), and only boys with uncorrected vision had more shoulder pain in general/during screen use (76 vs. 28/31%, p < 0.001; 2.2/2.4 vs. 0.7 mean pain score, p < 0.001), compared with children with normal vision.

CONCLUSIONS

The results of this study showed that even small refractive errors may impact educational outcomes and musculoskeletal pain in adolescents. Most of the participating children had low myopia, easily corrected with glasses. This suggests that regular eye examinations are important in school children, and there is a need for raised awareness among parents, and school- and healthcare personnel.

Vestibulo-Ocular Reflex Suppression: Clinical Relevance and Assessment in the Digital Age

Background

Visual acuity and image stability are crucial for daily activities, particularly during head motion. The vestibulo-ocular reflex (VOR) and its suppression (VORS) support stable fixation of objects of interest. The VOR drives a reflexive eye movement to counter retinal slip of a stable target during head motion. In contrast, VORS inhibits this countermovement when the target stimulus is in motion. The VORS allows for object fixation when it aligns with the direction of the head's movement, or when an object within or outside the peripheral vision needs to be focused upon.

Summary

Deficits of the VORS have been linked to age-related diseases such as balance deficits associated with an increased fall risk. Therefore, the accurate assessment of the VORS is of particular clinical relevance. However, current clinical assessment methods for VORS are mainly qualitative and not sufficiently standardised. Recent advances in digital health technology, such as smartphone-based videooculography, offer a promising alternative for assessing VORS in a more accessible, efficient, and quantitative manner. Moreover, integrating mobile eye-tracking technology with virtual reality environments allows for the implementation of controlled VORS assessments with different visual inputs. These assessment approaches allow the extraction of novel parameters with potential pathomechanistic and clinical relevance.

Key Messages

We argue that researchers and clinicians can obtain a more nuanced understanding of this ocular stabilisation reflex and its associated pathologies by harnessing digital health technology for VORS assessment. Further research is warranted to explore the technologies' full potential and utility in clinical practice.

The relationship of cervicothoracic mobility restrictions to fall risk and fear of falling in ankylosing spondylitis

Objective

The objective of this study is to determine whether restricted cervical mobility in ankylosing spondylitis (AS) is associated with increased fall frequency or fear of falling.

Methods

A total of 134 AS patients and 199 age- and gender-matched control subjects (CS) with soft-tissue cervicothoracic pain were prospectively evaluated for fall risk. Subjects were divided into non-fallers, single fallers, and multiple fallers. Dynamic cervical rotations and static cervicothoracic axial measurements were compared between the groups. In total, 88 AS patients were reviewed more than once; Kaplan-Meier plots were constructed for fall risk as a function of cervical rotation amplitudes. Falls Efficacy Scale-International (FES-I) questionnaire measured the fear of falling.

Results

In total, 34% of AS patients and 29% of CS fell (p = 0.271) in the year prior to evaluation. In AS, static anatomical measurements were unrelated to fall occurrence. The trends of multiple AS fallers to greater flexed forward postures and reduced dynamic cervical rotations were not statistically significant. Cervicothoracic pain (p = 0.0459), BASDAI (p = 0.002), and BASFI (p = 0.003) scores were greater in multiple fallers. FES-I scores were greater in fallers (p = 0.004). Of the 88 AS patients reviewed (or seen) on more than one occasion, 46.5% fell over the 9-year observation period, including all multiple fallers and 71.4% of single fallers. Survival curves showed increased fall risk as cervical rotational amplitudes decreased.

Conclusion

In AS, decreased cervical rotations increase fall risk and fear of falling. In multiple fallers, falls were associated with greater disease activity. Cervical muscle stiffness in AS may cause non-veridical proprioceptive inputs and contribute to increased fall frequency similar to individuals with soft-tissue cervicothoracic pain.

Proprioceptive Cervicogenic Dizziness Care Trajectories in Patient Subpopulations: A Scoping Review

Proprioceptive cervicogenic dizziness (PCGD) is the most prevalent subcategory of cervicogenic dizziness. There is considerable confusion regarding this clinical syndrome's differential diagnosis, evaluation, and treatment strategy. Our objectives were to conduct a systematic search to map out characteristics of the literature and of potential subpopulations of PCGD, and to classify accordingly the knowledge contained in the literature regarding interventions, outcomes and diagnosis. A Joanna Briggs Institute methodology-informed scoping review of the French, English, Spanish, Portuguese and Italian literature from January 2000 to June 2021 was undertaken on PsycInfo, Medline (Ovid), Embase (Ovid), All EBM Reviews (Ovid), CINAHL (Ebsco), Web of Science and Scopus databases. All pertinent randomized control trials, case studies, literature reviews, meta-analyses, and observational studies were retrieved. Evidence-charting methods were executed by two independent researchers at each stage of the scoping review. The search yielded 156 articles. Based on the potential etiology of the clinical syndrome, the analysis identified four main subpopulations of PCGD: chronic cervicalgia, traumatic, degenerative cervical disease, and occupational. The three most commonly occurring differential diagnosis categories are central causes, benign paroxysmal positional vertigo and otologic pathologies. The four most cited measures of change were the dizziness handicap inventory, visual analog scale for neck pain, cervical range of motion, and posturography. Across subpopulations, exercise therapy and manual therapy are the most commonly encountered interventions in the literature. PCGD patients have heterogeneous etiologies which can impact their care trajectory. Adapted care trajectories should be used for the different subpopulations by optimizing differential diagnosis, treatment, and evaluation of outcomes.

Laboured reading and musculoskeletal pain in school children - the role of lifestyle behaviour and eye wear: a cross-sectional study

Background

Lifestyle behaviour in children and adolescents has become increasingly sedentary and occupied with digital work. Concurrently, there has been an increase in the prevalence of headache, neck- and low back pain, which are leading causes of disability globally. Extensive near work and use of digital devices are demanding for both the visual system and the upper body head-stabilizing musculature. Uncorrected vision problems are present in up to 40% of Nordic school children, and a lack of corrective eye wear may cause eyestrain, musculoskeletal pain and headache. The aim of this study was to investigate associations between laboured reading, musculoskeletal pain, uncorrected vision, and lifestyle behaviours in children and adolescents.

Methods

This was a cross-sectional study with a total of 192 Norwegian school children aged 10–11 and 15–16 years. As a part of a school vision testing program, the children completed an online questionnaire about general and ocular health, socioeconomic status, academic ambition, near work and related symptoms, upper body musculoskeletal pain, and physical and outdoor activities.

Results

The 15–16-year-olds had a more indoor, sedentary, digital-based lifestyle with higher academic demands, compared with the 10–11-year-olds. Concurrently, reading became more laboured and upper body musculoskeletal pain increased with age. Girls reported more symptoms, higher academic ambitions, and more time spent on schoolwork and reading, compared with boys. Non-compliance in wearing prescribed eye wear (glasses or contact lenses), increased use of near digital devices, and experiencing visual stress (glare) were positively associated with laboured reading and upper body musculoskeletal pain.

Conclusions

A screen-based lifestyle with high academic demands challenges the ability to sustain long hours of static, intensive near work. Extensive near work tires the visual system and upper body musculature and provokes laboured reading and musculoskeletal pain symptoms. This study emphasizes the importance of regular eye examinations in school children, and the need to raise awareness among children, parents, and school- and health personnel about the importance of optimal vision and visual environment for academic performance and health.

Is Altered Oculomotor Control during Smooth Pursuit Neck Torsion Test Related to Subjective Visual Complaints in Patients with Neck Pain Disorders?

Subjective visual complaints are commonly reported in patients with neck pain, but their relation to objectively measured oculomotor functions during smooth pursuit neck torsion tests (SPNTs) has not yet been investigated. The aim of the study was to analyse classification accuracy of visual symptom intensity and frequency based on SPNT results. Forty-three patients with neck pain were referred by orthopaedic outpatient clinics where they were required to fill out 16-item proformas of visual complaints. Infrared video-oculography was used to measure smooth pursuit eye movements during neutral and neck torsion positions. Parameters of gain and SPNT difference (SPNTdiff) were taken into the Naïve Bayes model as classifiers, while intensity and frequency of visual symptoms were taken as predicted class. Intensity and, to a lesser degree, frequency of visual symptoms previously associated with neck pain or focal vision disorders (computer vision syndrome) showed better classification accuracy using gain at neck torsion position, indicating cervical driven visual disturbances. Moreover, SPNTdiff presented with slightly lower classification accuracy as compared to gain at neck torsion position. Our study confirmed the relationship between cervical driven oculomotor deficits and some visual complaints (concentrating to read, words moving on page, blurred vision, difficulty judging distance, sore eyes, heavy eyes, red eyes, and eyes strain).

The Enduring Controversy of Cervicogenic Vertigo, and Its Place among Positional Vertigo Syndromes

The idea of cervicogenic vertigo (CV) was proposed nearly a century ago, yet despite considerable scrutiny and research, little progress has been made in clarifying the underlying mechanism of the disease, developing a confirmatory diagnostic test, or devising an appropriately targeted treatment. Given the history of this idea, we offer a review geared towards understanding why so many attempts at clarifying it have failed, with specific comments regarding how CV fits into the broader landscape of positional vertigo syndromes, what a successful diagnostic test might require, and some practical advice on how to approach this in the absence of a diagnostic test.

Headache and musculoskeletal pain in school children are associated with uncorrected vision problems and need for glasses: a case-control study

Musculoskeletal pain and headache are leading causes of years lived with disability, and an escalating problem in school children. Children spend increasingly more time reading and using digital screens, and increased near tasks intensify the workload on the precise coordination of the visual and head-stabilizing systems. Even minor vision problems can provoke headache and neck- and shoulder (pericranial) pain. This study investigated the association between headaches, pericranial tenderness, vision problems, and the need for glasses in children. An eye and physical examination was performed in twenty 10–15 year old children presenting to the school health nurse with headache and pericranial pain (pain group), and twenty age-and-gender matched classmates (control group). The results showed that twice as many children in the pain group had uncorrected vision and needed glasses. Most children were hyperopic, and glasses were recommended mainly for near work. Headache and pericranial tenderness were significantly correlated to reduced binocular vision, reduced distance vision, and the need for new glasses. That uncorrected vision problems are related to upper body musculoskeletal symptoms and headache, indicate that all children with these symptoms should have a full eye examination to promote health and academic performance.

Cervicothoracic Mechanical Impairment as Part of Complete Neurological Fall Risk Appraisal

BACKGROUND

Assessment of individuals at risk for falling entails comprehensive neurological and vestibular examinations. Chronic limitation in cervical mobility reduces gaze accuracy, potentially impairing navigation through complex visual environments. Additionally, humans with scoliosis have altered otolithic vestibular responses, causing imbalance. We sought to determine whether dynamic cervical mobility restrictions or static cervicothoracic impairments are also fall risk factors.

METHODS

We examined 435 patients referred for soft-tissue musculoskeletal complaints; 376 met criteria for inclusion (mean age 52; 266 women). Patients were divided into nonfallers, single fallers, and multiple fallers, less or greater than 65 years old. Subject characteristics, dynamic cervical rotations, and static cervicothoracic axial measurements were compared between groups. Fear of falling was evaluated using the Falls Efficacy Scale-International questionnaire.

RESULTS

Long-standing cervicothoracic pain and stiffness conferred increased risk of falling. Neck rotation amplitudes decreased with longer duration musculoskeletal symptoms and were significantly more restricted in fallers, doubling the risk of falling and contributing to increased fear of falling. Mid-thoracic scoliosis amplitudes increased over time, but static axial abnormalities were not greater among fallers, although thoracic kyphoscoliosis heightened fear of falling.

CONCLUSION

In patients at fall risk, thoracic kyphoscoliosis and dynamic neck movements should be assessed, in addition to standard vestibular and neurological evaluations. Additionally, patients with soft tissue cervicothoracic pain and restricted mobility have increased fall frequency and fear of falling, independent of other fall risk factors and should undergo complete fall risk appraisal.

Symptoms in cervical vertigo

OBJECTIVE

To use a unique, 41-question survey to identify patient features distinguishing cervical vertigo from vestibular causes of vertigo and vestibular migraine.

METHODS

In this study, a unique, 41-question survey was administered to 48 patients diagnosed with cervical vertigo (n = 16), migraine (n = 16), and vestibular vertigo (eg, unilateral vestibular paresis, Meniere's disease) (n = 16) to test the hypothesis that a set of distinct symptoms can characterize cervical vertigo. Responses between the three diagnostic groups were compared to identify questions which differentiated patients based on their symptoms.

RESULTS

Eight questions were successful in differentiating vestibular vertigo from migraine and cervical vertigo. Symptoms endorsed by subjects with cervical vertigo overlapped substantially with subjects with well-established vestibular disturbances as well as symptoms of subjects with migraine. Twenty-seven percent of cervical vertigo subjects reported having true vertigo, 50% having headache, and 94% having neck pain.

CONCLUSION

Lacking knowledge of neck disturbance, the symptoms we elicited in our questionnaire suggest that cervical vertigo subjects may resemble migraine subjects who also have evidence of neck injury. Whether or not subjects with "cervical vertigo" also overlap with other diagnoses defined by a combination of symptoms and exclusion of objective findings such as chronic subjective dizziness and other variants of psychogenic dizziness remain to be established.

LEVEL OF EVIDENCE

IV.