The influence of cervical movement on eye stabilization reflexes: a randomized trial

Cervico-Ocular and Vestibulo-Ocular Reflexes in Subclinical Neck Pain and Healthy Individuals: A Cross-Sectional Study

Alterations in neck sensory input from recurrent neck pain (known as subclinical neck pain (SCNP)) result in disordered sensorimotor integration (SMI). The cervico-ocular (COR) and vestibulo-ocular (VOR) reflexes involve various neural substrates but are coordinated by the cerebellum and reliant upon proprioceptive feedback. Given that proprioception and cerebellar processing are impaired in SCNP, we sought to determine if COR or VOR gain is also altered. COR and VOR were assessed using an eye-tracking device in 20 SCNP (9 M and 11 F; 21.8 (SD = 2.35) years) and 17 control (7 M and 10 F; 22.40 (SD = 3.66) years) participants. COR gain (10 trials): A motorized chair rotated the trunk at a frequency of 0.04 Hz and an amplitude of 5° while participants gazed at a circular target that disappeared after three seconds. VOR gain (30 trials): Rapid bilateral head movements away from a disappearing circular target while eyes fixated on the last observed target. Independent t-tests on COR and VOR gain were performed. SCNP had a significantly larger COR gain (p = 0.006) and smaller VOR gain (p = 0.487) compared to healthy controls. The COR group differences suggest an association between proprioceptive feedback and SMI, indicating COR may be a sensitive marker of altered cerebellar processing.

Short-Term Effect of Spinal Manipulation on the Magnitude of Exophoria in Adults Who Are Asymptomatic: A Randomized Controlled Trial

OBJECTIVE

This study aimed to assess the immediate and short-term effects of cervical spinal manipulation (SM), compared with a placebo, on the magnitude of near and distance exophoria in adults with asymptomatic exophoria.

METHODS

In this single-blind, randomized controlled trial, individuals with a clinical diagnosis of horizontal exophoria confirmed with the prism alternating cover test (PACT) were allocated to a single intervention session using a high-velocity, low-amplitude cervical SM technique or a sham intervention (manual contact under the head). Outcomes were the magnitude of horizontal heterophoria, as a measure of binocular vision efficiency at near (40 cm) or distance (4 m) fixation, using the PACT. Evaluations were made at baseline, immediately after intervention, and at a 1-week follow-up.

RESULTS

From May to September 2021, 44 volunteers (23 women), with a mean age of 35 (SD = 9.5) years, were recruited and equally distributed into the study groups. All participants completed follow-up assessments, and no adverse events were reported. There was a significant time × group interaction for exophoria at near vision, but not at distance fixation. The SM group showed a significant decrease of near exophoria compared with the control group at the 1-week follow-up (mean difference = -1.09 prism diopters; 95% CI = -0.20 to -1.98 prism diopters).

CONCLUSION

The use of cervical SM therapy resulted in a significant reduction of the magnitude of horizontal exophoria at near vision (medium effect size), compared with the placebo, in young adults who are asymptomatic. However, these effects were not observed at distance fixation and should be considered cautiously due to the pre-post design with a single intervention session and the short-term follow-up.

IMPACT

The findings suggest short-term benefits of SM therapy can manage undiagnosed ocular convergence disorders, although changes were not clinically relevant.

Cervical mobility and cervical proprioception in relation to fall risk among older adults: a prospective cohort study

PURPOSE

Age-related decreases in cervical mobility and proprioception have previously been demonstrated. Potential associations of these deteriorations with fall risk have not been investigated so far. This study aims to compare cervical mobility and proprioception between fallers and non-fallers and prospectively assess the contribution of these parameters in fall risk identification among healthy older adults.

METHODS

95 community-dwelling older adults underwent a cervical screening. Active cervical range of motion (aCROM) was measured using a digital inclinometer and cervical proprioception was assessed by determining joint position error (JPE). Fear of falling was identified through the Iconographical Falls Efficacy Scale (iconFES). Falls were prospectively recorded during a 1-year follow-up period using monthly calendars. Univariate and multivariate logistic regression analyses were conducted to examine the association between these parameters and falls occurrence.

RESULTS

Baseline measurements revealed reduced cervical performance (i.e., smaller aCROM and larger JPE) among individuals who reported at least one fall during the following year ("fallers"). The multivariate logistic regression model contained eight independent variables (age, sex, walking aid, fall history, iconFES, aCROM F, aCROM E and JPE) and correctly classified 77.8% of cases.

CONCLUSION

Although the contribution of cervical parameters to fall risk identification seems to be rather small compared to well-known (though often unmodifiable) major risk factors, further research is needed to elucidate underlying mechanisms of cervical functions in relation to falls. Second, it would be interesting to develop a targeted fall preventive cervical exercise program and assess its effectiveness in terms of falls occurrence.

Effectiveness of adding rehabilitation of cervical related sensorimotor control to manual therapy and exercise for neck pain: A randomized controlled trial

BACKGROUND

Local neck treatments and sensorimotor training can improve cervical proprioception and balance, but it remains unclear what treatments and treatment combination achieve the best outcomes.

OBJECTIVES

To investigate the most effective interventions to improve disturbances in joint position sense (JPS) and balance and their effects on neck pain, dizziness and related features in the short- and long-terms.

DESIGN

2x2 factorial, randomized controlled trial.

METHODS

Participants with neck pain (n = 152) were randomly allocated to one of four intervention groups: i) local neck treatment (NT), ii) NT + JPS/oculomotor exercises (JPS/OC), iii) NT + balance exercises, and iv) all treatments. Participants received 12 treatments over 6 weeks. Primary outcomes were postural sway and joint position error. Secondary outcomes included gait speed, dizziness, pain intensity and disability, cervical range of motion, functional ability, and quality of life. Outcome measures were taken at baseline, posttreatment and 3-, 6- and 12-month follow-ups.

RESULTS

All four interventions resulted in short- and long-term improvements in primary and secondary outcomes with medium to large effect sizes, but JPS and balance in neck torsion improved most with the addition of a combined program of JPS/OC + balance exercises to NT while balance in neck neutral improved most with the addition of balance exercises. Adding sensorimotor training was also more effective in maintaining levels of improvement in neck pain and disability at 6- and 12-months. Effect sizes of additional treatment benefits were medium to large.

CONCLUSIONS

Adding specific training of JPS/OC and balance to NT best addresses deficits in cervical proprioception and balance.

CLINICAL TRIAL REGISTRATION NUMBER

xxxxx.

Physical ability, cervical function, and walking plantar pressure in frail and pre-frail older adults: An attentional focus approach

Aging and increased vulnerability define the clinical condition of frailty. However, while the cervical function is recognized as a determinant of balance and walking performance, no study simultaneously physical ability, cervical function, balance, and plantar pressure distribution in walking in nursing house population. Thus, the present study aimed to compare these parameters between Frail and Pre-Frail aged people. Thirty-one (12 men and 19 women) institutionalized participants (age: 89.45 ± 5.27 years, weight: 61.54 ± 9.99 kg, height: 160.34 ± 7.93 cm) were recruited and divided into Pre-Frail and Frail groups according to SPPB (Short Physical Performance Battery) score (Frail <6, Pre-Frail ≥6). Participants performed the Timed Up and Go Test (TUGT) and a static balance evaluation. The cervical range of motion (COM), knee extensor strength, and walking plantar pressure distribution have been measured. The Pre-Frail group showed a higher gait speed (ES = 0.78, p ≤ 0.001) and a better TUGT, as well as higher knee extensor strength (ES = 0.4, p = 0.04). Furthermore, the Pre-Frail group presented a center of pressure (COP) displacement velocity on the sagittal axis (ES = 0.43, p = 0.02) and a more COP projection on this axis (ES = 0.43, p = 0.02). No significant difference has been observed between the two groups concerning the total contact time and most of the plantar pressure parameters except for the rear foot relative contact time which was lower in the Pre-Frail group. The Pre-Frail group also showed better cervical tilt mobility (ES = 0.35, p = 0.04). This study highlights the influence of some new parameters on frailty in older people, such as cervical mobility and plantar pressure distribution in walking.

Design and Development of a Rotating Chair to Measure the Cervico-Ocular Reflex

Eye reflexes that stabilize gaze are essential in navigating daily life. One such reflex is the cervico-ocular reflex (COR). An important neural structure involved in the COR is the cerebellum, which facilitates proper gaze stability through sensorimotor integration to adjust eye movements accordingly. This reflex is tested by fixating the head in space and rotating the body around the neck. Thus, a rotating chair is needed to elicit proper cervical rotation while keeping the head fixed. The chair that was developed for this project was able to rotate to the specified amplitude (±0.5º of accuracy) and frequency. The parameters of the rotation amount, frequency, and amplitude can be adjusted as desired by the project guidelines. Our project aimed to improve upon existing chair models and develop a chair that can be used to assess the COR in neck pain populations.

Nonvestibular Dizziness

Dizziness is a common chief complaint with an extensive differential diagnosis that ranges from peripheral, central, to nonvestibular conditions. An understanding of nonvestibular conditions will aid accurate diagnosis and initiation of appropriate management. Thus, the objective of this article is to present an overview of nonvestibular etiologies that may plague a dizzy patient and the recommended treatment options.

Modification of Eye-Head Coordination With High Frequency Random Noise Stimulation

The vestibulo-ocular reflex (VOR) plays an important role in controlling the gaze at a visual target. Although patients with vestibular hypofunction aim to improve their VOR function, some retain dysfunction for a long time. Previous studies have explored the effects of direct current stimulation on vestibular function; however, the effects of random noise stimulation on eye–head coordination have not previously been tested. Therefore, we aimed to clarify the effects of high frequency noisy vestibular stimulation (HF-nVS) on eye–head coordination related to VOR function. Thirteen healthy young adult participants with no serious disease took part in our study. The current amplitude and density used were 0.4 mA and 0.2 mA/cm², respectively, with a random noise frequency of 100–640 Hz. The electrodes were located on both mastoid processes. The stimulus duration and fade in/out duration were 600 and 10 s, respectively. Subjects oscillated their head horizontally, gazing at the fixation point, at 1 Hz (0.5 cycles/s) for 30 repetitions. The coordination of eye–head movements was measured by eye-tracking and a motion capture system. Peak-to-peak angles for eye and head movement and deviation of the visual line from the fixation target revealed no significant differences between HF-nVS and sham. The lag time between the eye and head movement with HF-nVS post-stimulation was significantly shorter than that of the sham. We found that HF-nVS can reduce the lag time between eye and head movement and improve coordination, contributing to a clear retinal image. This technique could be applied as a form of VOR training for patients with vestibular hypofunction.

Clinical application of 3D-VOG analysis for quantitative evaluation of Otolith-Ocular reflex in the roll and pitch planes

BACKGROUND

Management of vestibular falls requires precise evaluation of otolithic function and gravity recognition. Tilt of the head in the roll plane causes ocular counter rolling (OCR) with a gain of 5-10%, which can be a quantitative parameter related to the otolith-ocular reflex (OOR) in that plane. However, the OOR in the pitch plane is indiscernible because of our ability to voluntarily gaze and pursue. 3 D eye movements and its Listing's plane description can provide novel parameters with which to evaluate OOR, even in the pitch plane.

OBJECTIVES

To evaluate the utility of 3 D eye movement analysis in video oculography (VOG) as a quantitative parameter reflecting otolithic function during head movements associated with daily life.

MATERIALS AND METHODS

In healthy subjects, we analyzed the changes in 3 D eye movements and the Listing's plane that occur with static gravitational modification.

RESULTS

OOR during head tilt in the roll plane revealed that OCR amplitude had a saturating/peaked conformation and was not fitted by a sine curve. OOR in the pitch plane revealed anteroposterior leaning of the Listing's plane.

CONCLUSIONS

These novel tools for minimally invasive evaluation of OOR in a clinical setting could potentially enable us to quantitatively evaluate peripheral static disequilibrium.

Patient-reported outcomes measured with and without dizziness associated with non-specific chronic neck pain: implications for primary care

Background

The aim of this study was to compare health-related quality of life (HRQoL) and disability and fear of movement in patients with non-specific chronic neck pain (NSCNP) associated with dizziness with respect to patients with isolated NSCNP in primary care settings.

Methods

A cross-sectional study was carried out in a primary care center. A total of 120 patients were divided into two groups and analyzed in this study. One group of patients reported dizziness combined with NSCNP (n = 60), and the other reported no dizziness with their NSCNP (n = 60). Patient-reported outcome measurements were HRQoL (primary outcome) and disability and kinesiophobia (secondary outcomes) assessed by the EuroQoL Five Dimensions and Five Levels (EQ-5D-5L), neck disability index (NDI) and Tampa Scale of Kinesiophobia (TSK-11), respectively.

Results

Statistically significant differences (P < 0.05) for a 95% confidence interval (CI) with a large effect size (Cohen d) were found between both groups with greater values of disability (mean difference = 6.30 points; 95% CI [3.84-8.75]; d = 0.94) and kinesiophobia (mean difference = 8.36 points; 95% CI [6.07-10.65]; d = 1.33), and an impairment of HRQoL (mean difference = 16.16 points; 95% CI [11.09-21.23]; d = 1.16), for patients with NSCNP associated with dizziness with respect to patients with isolated NSCNP.

Conclusions

Patients with NSCNP in conjunction with dizziness present higher HRQoL impairment and higher disability and kinesiophobia compared to patients with isolated NSCNP.