The cervico-ocular reflex changes following treatment in individuals with subclinical neck pain: a randomized control trial.

Individuals with subclinical neck pain (SCNP) exhibit altered cerebellar processing, likely due to disordered sensorimotor integration of inaccurate proprioceptive input. This association between proprioceptive feedback and SMI has been captured in cervico-ocular reflex (COR) differences where SCNP showed higher gain than healthy participants. Previous neurophysiological research demonstrated improved cerebellar processing in SCNP participants following a single treatment session, but it is unknown whether these neurophysiological changes transfer to cerebellar function. In a parallel group, randomized control trial conducted at Ontario Tech University, 27 right-hand dominant SCNP participants were allocated to the 8-week chiropractic care (n = 15; 7M & 8 F) or 8-week control (n = 12; 6M & 6 F) group. COR gain (ratio of eye movement to trunk movement) was assessed using an eye-tracking device at baseline and at post 8-weeks (treatment vs. no treatment). COR gain (10 trials): participants gazed at a circular target that disappeared after 3 s, while a motorized chair rotated their trunk at a frequency of 0.04 Hz, with an amplitude of 5º, for 2 minutes. A 2 × 2 repeated measures ANOVA was performed. COR gain was significantly reduced following 8-weeks of chiropractic care compared to the SCNP control (8-weeks of no treatment) group (p = 0.012, ηp2 = 0.237). The decrease in COR gain following treatment is likely due to normalized proprioceptive feedback from the neck, enabling improved processing and integration within the flocculonodular lobe of the cerebellum.

Subclinical Neck Pain Leads to Differential Changes in Early Somatosensory Evoked Potentials in Response to a Novel Force Matching Tracking Task.

BACKGROUND: Neural adaptions in response to sensorimotor tasks are impaired in those with untreated, recurrent mild-to-moderate neck pain (subclinical neck pain (SCNP)), due to disordered central processing of afferent information (e.g., proprioception). Neural adaption to force modulation, a sensorimotor skill reliant on accurate proprioception, is likely to be impaired in those with SCNP. This study examined changes in somatosensory evoked potential (SEP) peak amplitudes following the acquisition of a novel force matching tracking task (FMTT) in those with SCNP compared to non-SCNP. METHODS: 40 (20 female (F) & 20 male (M); average age (standard deviation, SD): 21.6 (3.01)) right-handed participants received controlled electrical stimulation at 2.47 Hz and 4.98 Hz (averaged 1000 sweeps/frequency) over the right-median nerve, to elicit SEPs before and after FMTT acquisition. Participants used their right thumb to match a series of force profiles that were calibrated to their right thumb (abductor pollicis brevis muscle) strength. To determine if motor learning was impacted, retention was assessed 24 to 48 hours later. Outliers were removed before running independent t-tests on normalized SEP peak amplitudes, and repeated measures analysis of variance (ANOVA) with planned contrasts on absolute and normalized motor performance accuracy. Benjamini-hochberg test was used to correct for multiple independent SEP comparisons. RESULTS: SEP peaks: N18 (t(29.058) = 2.031, p = 0.026), N20 (t(35) = -5.460, p < 0.001), and P25 (t(33) = -2.857, p = 0.004) had group differences. Motor performance: Absolute error (n = 38) had a main effect of time, and significant pre-and post-acquisition contrast for time (both p < 0.001). CONCLUSIONS: Group differences in the olivary-cerebellar pathway (N18), and cortical processing at the somatosensory cortex (N20 and P25), suggests that SCNP alters cortical and cerebellar processing compared to non-SCNP in response to FMTT acquisition. The sensory-motor integration differences in the SCNP group suggests that those with SCNP may rely more on feedback loops for discrete sensorimotor tasks dependent on proprioception. Early SEP changes may be used as a marker for altered neuroplasticity in the context of motor skill acquisition of a novel discrete FMTT in those with SCNP.

Sensorimotor integration and motor learning during a novel visuomotor tracing task in young adults with attention-deficit/hyperactivity disorder.

Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder that has noted alterations to motor performance and coordination, potentially affecting learning processes and the acquisition of motor skills. This work will provide insight into the role of altered neural processing and sensorimotor integration (SMI) while learning a novel visuomotor task in young adults with ADHD. This work compared adults with ADHD (n = 12) to neurotypical controls (n = 16), using a novel visuomotor tracing task, where participants used their right-thumb to trace a sinusoidal waveform that varied in both frequency and amplitude. This learning paradigm was completed in pre, acquisition, and post blocks, where participants additionally returned and completed a retention and transfer test 24 h later. Right median nerve short latency somatosensory-evoked potentials (SEPs) were collected pre and post motor acquisition. Performance accuracy and variability improved at post and retention measures for both groups for both normalized (P < 0.001) and absolute (P < 0.001) performance scores. N18 SEP: increased in the ADHD group post motor learning and decreased in controls (P < 0.05). N20 SEP: increased in both groups post motor learning (P < 0.01). P25: increased in both groups post motor learning (P < 0.001). N24: increased for both groups at post measures (P < 0.05). N30: decreased in the ADHD group and increased in controls (P < 0.05). These findings suggest that there may be differences in cortico-cerebellar and prefrontal processing in response to novel visuomotor tasks in those with ADHD.NEW & NOTEWORTHY Alterations to somatosensory-evoked potentials (SEPs) were present in young adults with attention-deficit/hyperactivity disorder (ADHD), when compared with neurotypical controls. The N18 and N30 SEP peak had differential changes between groups, suggesting alterations to olivary-cerebellar-M1 processing and SMI in those with ADHD when acquiring a novel visuomotor tracing task. This suggests that short-latency SEPs may be a useful biomarker in the assessment of differential responses to motor acquisition in those with ADHD.

Differential changes in somatosensory evoked potentials and motor performance: pursuit movement task versus force matching tracking task.

Force modulation relies on accurate proprioception, and force-matching tasks alter corticocerebellar connectivity. Corticocerebellar (N24) and corticomotor pathways are impacted following the acquisition of a motor tracing task (MTT), measured using both somatosensory evoked potentials (SEPs) and transcranial magnetic stimulation. This study compared changes in early SEP peak amplitudes and motor performance following a force-matching tracking task (FMTT) to an MTT. Thirty (18 females) right-handed participants, aged 21.4 ± 2.76, were electrically stimulated over the right-median nerve at 2.47 Hz and 4.98 Hz (averaged 1,000 sweeps/rate) to elicit SEPs, recorded via a 64-channel electroencephalography cap, before, and after task acquisition using the right abductor pollicis brevis muscle. Retention was measured 24 h later. Significant time-by-group interactions occurred for the N20 SEP: 6.3% decrease post-FMTT versus 5.5% increase post-MTT (P = 0.013); P25 SEP: 4.0% decrease post-FMTT versus 10.3% increase post-MTT (P = 0.006); and N18 SEP: 113.4% increase post-FMTT versus 4.4% decrease post-MTT (P = 0.006). N18 and N30 showed significant effect of time (both P < 0.001). Motor performance: significant time-by-group interactions-postacquisition: FMTT improved 15.3% versus 24.3% for MTT (P = 0.025), retention: FMTT improved 17.4% and MTT by 30.1% (P = 0.004). Task-dependent differences occurred in SEP peaks associated with cortical somatosensory processing (N20 and P25), and cerebellar input (N18), with similar changes in sensorimotor integration (N30), with differential improvements in motor performance, indicating important differences in cerebellar and sensory processing for tasks reliant on proprioception.NEW & NOTEWORTHY This study demonstrates neurophysiological differences in cerebellar and somatosensory cortex pathways when learning a motor task requiring visuomotor tracking versus a task that requires force-matching modulation, in healthy individuals. The clear neurophysiological differences in early somatosensory evoked potentials associated with cortical somatosensory processing, cerebellar input, and sensorimotor integration between these two tasks demonstrate some of the neural correlates of force modulation and validate the force-matching task for use in future work.

Neck muscle fatigue impacts plasticity and sensorimotor integration in cerebellum and motor cortex in response to novel motor skill acquisition.

The cerebellum undergoes neuroplastic changes in response to motor learning. Healthy human individuals demonstrate reduced cerebellar inhibition (CBI) following motor learning. Alterations in neck sensory input due to muscular fatigue are known to impact upper limb sensorimotor processing, suggesting that neck fatigue may also impact cerebellum to motor cortex (M1) pathways in response to motor learning. Therefore, this study aimed to determine whether cervical extensor muscle (CEM) fatigue alters CBI in response to motor learning. We examined 16 participants (8 CEM fatigue and 8 CEM control). A double cone transcranial magnetic stimulation (TMS) coil stimulated the ipsilateral cerebellar cortex 5 ms before application of contralateral test stimuli of the M1 to the right first dorsal interosseous muscle. Cerebellar-M1 activity curves were established pre- and post-motor skill acquisition (consisting of tracing sinusoidal-pattern waves with the index finger) and following either the CEM fatigue or control intervention. The control group showed greater cerebellar disinhibition than the fatigue group following motor skill acquisition (P < 0.006), while the fatigue group showed similar levels of CBI pre- and post-motor skill acquisition. Both groups improved in accuracy following acquisition (P = 0.012) and retention (P = 0.007), but the control group improved significantly more (17% at acquisition and 22% at retention) versus lower (6% and 9%) improvements for the fatigue group. Lessened cerebellar disinhibition in the CEM fatigue versus control group, coupled with diminished motor learning, suggests that CEM fatigue affects the cerebellar-M1 interaction, influencing the cerebellum's ability to adjust motor output to acquire and learn a novel motor task.NEW & NOTEWORTHY Normally motor learning decreases cerebellar inhibition (CBI) to facilitate learning of a novel skill. In this study, neck fatigue before motor skill acquisition led to less of a decrease in CBI and significantly less improvement in performance accuracy relative to a control group. This study demonstrated that neck fatigue impacts the cerebellar-motor cortex interaction to distal hand muscles, a highly relevant finding due to the altered neck postures and fatigue accompanying increased technology use.

Development of the Sensory-Motor Dysfunction Questionnaire and Pilot Reliability Testing.

Both chronic and recurrent spinal pain alter sensorimotor integration (SMI), which is demonstrated using complex neurophysiological techniques. Currently, there is no patient-reported outcome measure that documents and/or assesses SMI in populations with spinal problems. The purpose of this study was to develop the Sensory-Motor Dysfunction Questionnaire (SMD-Q) and assess its test-retest reliability and internal consistency in individuals with recurrent spinal pain. The SMD-Q was developed based on the existing literature on motor control disturbances associated with disordered SMI. The initial SMD-Q drafts underwent review by two separate panels of subject matter experts and a focus group with subclinical spine pain. Their suggestions were incorporated into the questionnaire prior to reliability testing. The questionnaire was administered twice at a seven-day interval using QualtricsTM. A total of 20 participants (14 females and 6 males; 20.95 ± 2.46 years of age) completed the study. Quadratic weighted kappa (Kw) was used to assess test-retest reliability and Cronbach's alpha (α) was used to assess internal consistency. Four items had a Kw < 0.40, seven had a 0.40 < Kw < 0.75, and one had a Kw > 0.75 (excellent agreement), with excellent internal consistency (α > 0.90). The pilot SMD-Q appears to reliably measure altered SMI, suggesting that revisions and testing with a larger sample are worth pursuing.

Impact of subclinical neck pain on eye and hand movements in goal-directed upper limb aiming movements.

Individuals with untreated, mild-to-moderate recurrent neck pain or stiffness (subclinical neck pain (SCNP)) have been shown to have impairments in upper limb proprioception, and altered cerebellar processing. It is probable that aiming trajectories will be impacted since individuals with SCNP cannot rely on accurate proprioceptive feedback or feedforward processing (body schema) for movement planning and execution, due to altered afferent input from the neck. SCNP participants may thus rely more on visual feedback, to accommodate for impaired cerebellar processing. This quasi-experimental study sought to determine whether upper limb kinematics and oculomotor processes were impacted in those with SCNP. 25 SCNP and 25 control participants who were right-hand dominant performed bidirectional aiming movements using two different weighted styli (light or heavy) while wearing an eye-tracking device. Those with SCNP had a greater time to and time after peak velocity, which corresponded with a longer upper limb movement and reaction time, seen as greater constant error, less undershoot in the upwards direction and greater undershoot in the downwards direction compared to controls. SCNP participants also showed a trend towards a quicker ocular reaction and movement time compared to controls, while the movement distance was fairly similar between groups. This study indicates that SCNP alters aiming performances, with greater reliance on visual feedback, likely due to altered proprioceptive input leading to altered cerebellar processing.

Neck Muscle Vibration Alters Cerebellar Processing Associated with Motor Skill Acquisition of a Proprioceptive-Based Task.

Experimentally induced neck fatigue and neck pain have been shown to impact cortico-cerebellar processing and sensorimotor integration, assessed using a motor learning paradigm. Vibration specifically impacts muscle spindle feedback, yet it is unknown whether transient alterations in neck sensory input from vibration impact these neural processing changes following the acquisition of a proprioceptive-based task. Twenty-five right-handed participants had electrical stimulation over the right median nerve to elicit short- and middle-latency somatosensory evoked potentials (SEPs) pre- and post-acquisition of a force matching tracking task. Following the pre-acquisition phase, controls (CONT, n = 13, 6 F) received 10 min of rest and the vibration group (VIB, n = 12, 6 F) received 10 min of 60 Hz vibration on the right sternocleidomastoid and left cervical extensors. Task performance was measured 24 h later to assess retention. Significant time by group interactions occurred for the N18 SEP peak, 21.77% decrease in VIB compared to 58.74% increase in CONT (F(1,23) = 6.475, p = 0.018, np2 = 0.220), and the N24 SEP peak, 16.31% increase in VIB compared to 14.05% decrease in CONT (F(1,23) = 5.787, p = 0.025, np2 = 0.201). Both groups demonstrated improvements in motor performance post-acquisition (F(1,23) = 52.812, p < 0.001, np2 = 0.697) and at retention (F(1,23) = 35.546, p < 0.001, np2 = 0.607). Group-dependent changes in the SEP peaks associated with cerebellar input (N18) and cerebellar processing (N24) suggests that an altered proprioceptive input from neck vibration impacts cerebellar pathways.

Effect Sizes for Changes in Health and Well-Being Following Treatment With the One-To-Zero Technique in Individuals With Occipito-Atlantal Joint Dysfunction: A Repeated Measures Study.

Objectives: The purpose of this study was to determine effect sizes (ES) for changes in self-reported measures of musculoskeletal pain and dysfunction resulting from the one-to-zero method using a repeated measures study design. Methods: Twenty participants presenting with articular dysfunction of the occipito-atlantal (C0-C1) complex were treated using the one-to-zero method, a high-velocity low-amplitude thrust administered between the C0-C1 complex before treating other restrictive segments in a cephalocaudal direction. The participants completed online questionnaires using Google Forms that assessed aspects of the biopsychosocial model of pain at baseline and within a week after treatment. The questionnaires included the following: (1) Demographic and Health Behavior Survey; (2) Neck Bournemouth Questionnaire (NBQ) or Neck Disability Index (NDI); (3) Beck Anxiety Index (BAI); (4) Insomnia Severity Index (ISI); and (5) 36-Item Short Form Health Survey (SF-36). Paired t test or Wilcoxon signed ranks test was performed, dependent on normality. Cohen's d values were calculated for each questionnaire score (0.20 indicative of small; ≥0.50 medium; and ≥0.80 large ES). Results: The NDI, NBQ, BAI, and ISI had a large ES (all d ≥ 0.80). In the SF-36, 4 subscales had a small to near-medium ES, 1 subscale had a medium to near-large ES, and the remaining 2 had a large ES (d ≥ 0.80). The physical and mental component summary had a large (d = 0.88) and small ES (d = 0.35), respectively. Conclusion: The effect sizes suggest the one-to-zero treatment induces change in various aspects of the biopsychosocial model.

Source Localization of Somatosensory Neural Generators in Adults with Attention-Deficit/Hyperactivity Disorder.

Attention-Deficit/Hyperactivity Disorder (ADHD) is a neurodevelopmental disorder, where differences are often present relating to the performance of motor skills. Our previous work elucidated unique event-related potential patterns of neural activity in those with ADHD when performing visuomotor and force-matching motor paradigms. The purpose of the current study was to identify whether there were unique neural sources related to somatosensory function and motor performance in those with ADHD. Source localization (sLORETA) software identified areas where neural activity differed between those with ADHD and neurotypical controls when performing a visuomotor tracing task and force-matching task. Median nerve somatosensory evoked potentials (SEPs) were elicited, while whole-head electroencephalography (EEG) was performed. sLORETA localized greater neural activity post-FMT in those with ADHD, when compared with their baseline activity (p < 0.05). Specifically, greater activity was exhibited in BA 31, precuneus, parietal lobe (MNI coordinates: X = -5, Y = -75, and Z = 20) at 156 ms post stimulation. No significant differences were found for any other comparisons. Increased activity within BA 31 in those with ADHD at post-FMT measures may reflect increased activation within the default mode network (DMN) or attentional changes, suggesting a unique neural response to the sensory processing of force and proprioceptive afferent input in those with ADHD when performing motor skills. This may have important functional implications for motor tasks dependent on similar proprioceptive afferent input.

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.

Neck Muscle Vibration Alters Upper Limb Proprioception as Demonstrated by Changes in Accuracy and Precision during an Elbow Repositioning Task.

Upper limb control depends on accurate internal models of limb position relative to the head and neck, accurate sensory inputs, and accurate cortical processing. Transient alterations in neck afferent feedback induced by muscle vibration may impact upper limb proprioception. This research aimed to determine the effects of neck muscle vibration on upper limb proprioception using a novel elbow repositioning task (ERT). 26 right-handed participants aged 22.21 ± 2.64 performed the ERT consisting of three target angles between 80−90° (T1), 90−100° (T2) and 100−110° (T3). Controls (CONT) (n = 13, 6F) received 10 min of rest and the vibration group (VIB) (n = 13, 6F) received 10 min of 60 Hz vibration over the right sternocleidomastoid and left cervical extensor muscles. Task performance was reassessed following experimental manipulation. Significant time by group interactions occurred for T1: (F1,24 = 25.330, p < 0.001, ηp2 = 0.513) where CONT improved by 26.08% and VIB worsened by 134.27%, T2: (F1,24 = 16.157, p < 0.001, ηp2 = 0.402) where CONT improved by 20.39% and VIB worsened by 109.54%, and T3: (F1,24 = 21.923, p < 0.001, ηp2 = 0.447) where CONT improved by 37.11% and VIB worsened by 54.39%. Improvements in repositioning accuracy indicates improved proprioceptive ability with practice in controls. Decreased accuracy following vibration suggests that vibration altered proprioceptive inputs used to construct body schema, leading to inaccurate joint position sense and the observed changes in elbow repositioning accuracy.

Source Localization of Audiovisual Multisensory Neural Generators in Young Adults with Attention-Deficit/Hyperactivity Disorder.

Attention-Deficit/Hyperactivity Disorder (ADHD) is a neurodevelopmental disorder that exhibits unique neurological and behavioural characteristics. Our previous work using event-related potentials demonstrated that adults with ADHD process audiovisual multisensory stimuli somewhat differently than neurotypical controls. This study utilised an audiovisual multisensory two-alternative forced-choice discrimination task. Continuous whole-head electroencephalography (EEG) was recorded. Source localization (sLORETA) software was utilised to determine differences in the contribution made by sources of neural generators pertinent to audiovisual multisensory processing in those with ADHD versus neurotypical controls. Source localization techniques elucidated that the controls had greater neural activity 164 ms post-stimulus onset when compared to the ADHD group, but only when responding to audiovisual stimuli. The source of the increased activity was found to be Brodmann Area 2, postcentral gyrus, right-hemispheric parietal lobe referenced to Montreal Neurological Institute (MNI) coordinates of X = 35, Y = −40, and Z = 70 (p < 0.05). No group differences were present during either of the unisensory conditions. Differences in the integration areas, particularly in the right-hemispheric parietal brain regions, were found in those with ADHD. These alterations may correspond to impaired attentional capabilities when presented with multiple simultaneous sensory inputs, as is the case during a multisensory condition.

Sensorimotor integration and motor learning during a novel force-matching task in young adults with attention-deficit/hyperactivity disorder.

Introduction: Attention-Deficit/Hyperactivity Disorder (ADHD) is a neurodevelopmental disorder that exhibits unique neurological and behavioral characteristics. Those with ADHD often have noted impairments in motor performance and coordination, including during tasks that require force modulation. The present study provides insight into the role of altered neural processing and SMI in response to a motor learning paradigm requiring force modulation and proprioception, that previous literature has suggested to be altered in those with ADHD, which can also inform our understanding of the neurophysiology underlying sensorimotor integration (SMI) in the general population. Methods: Adults with ADHD (n = 15) and neurotypical controls (n = 15) performed a novel force-matching task, where participants used their right-thumb to match a trace template that varied from 2-12% of their Abductor Pollicis Brevis maximum voluntary contraction. This motor task was completed in pre, acquisition, and post blocks. Participants also completed a retention test 24 h later. Median nerve somatosensory-evoked potentials (SEPs) were collected pre and post motor acquisition. SEPs were stimulated at two frequencies, 2.47 Hz and 4.98 Hz, and 1,000 sweeps were recorded using 64-electrode electroencephalography (EEG) at 2,048 Hz. SEP amplitude changes were normalized to each participant's baseline values for that peak. Results: Both groups improved at post measures (ADHD: 0.85 ± 0.09; Controls: 0.85 ± 0.10), with improvements maintained at retention (ADHD: 0.82 ± 0.11; Controls: 0.82 ± 0.11). The ADHD group had a decreased N18 post-acquisition (0.87 ± 0.48), while the control N18 increased (1.91 ± 1.43). The N30 increased in both groups, with a small increase in the ADHD group (1.03 ± 0.21) and a more pronounced increase in controls (1.15 ± 0.27). Discussion: Unique neural differences between groups were found after the acquisition of a novel force-matching motor paradigm, particularly relating to the N18 peak. The N18 differences suggest that those with ADHD have reduced olivary-cerebellar-M1 inhibition when learning a novel motor task dependent on force-modulation, potentially due to difficulties integrating the afferent feedback necessary to perform the task. The results of this work provide evidence that young adults with ADHD have altered proprioceptive processing when learning a novel motor task when compared to neurotypical controls.