Subclinical Neck Pain Research Articles

Known-Group Validity and Sensitivity to Change in the Sensory-Motor Dysfunction Questionnaire in Individuals with Neck Pain: A Pilot Study

Background/Objectives: Sensorimotor dysfunction is often reported in individuals experiencing neck pain, irrespective of severity and chronicity. The treatment of neck dysfunction has been found to positively impact sensorimotor integration (SMI), thereby improving sensorimotor function. However, no patient-reported outcome measure has been validated for discrimination between healthy individuals and neck pain patients with disordered SMI, nor has there been documentation of positive change in SMI following neck pain treatment.The purpose of this study was to administer the Sensory-Motor Dysfunction Questionnaire (SMD-Q), for the purposes of: (1) known-group validity between individuals without and with chronic neck pain (CNP) or subclinical neck pain (SCNP); (2) assess the questionnaire’s capacity to quantify changes in altered SMI following a tailored treatment plan. Methods: Part 1—Known Group Validity: The SMD-Q was administered to 30 neck pain (13 with CNP, and 17 with SCNP), and 30 healthy participants. Part 2—Sensitivity to Change: The SMD-Q was re-administered to neck pain participants following their tailored treatment plans (SCNP—8-weeks and CNP—12 weeks). Results: The SMD-Q can discriminate between healthy and neck pain participants (p ≤ 0.001), and may be sensitive to showing treatment effects (ηp2 = 0.162; large effect size (ES)), but the sample size was too small to determine if it can discriminate treatment effects between groups (ηp2 = 0.070; medium ES). Conclusions: Differing degrees of disordered SMI can be discriminated by the SMD-Q, but further research is needed to determine its sensitivity to treatment.

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 & 8F) or 8-week control (n = 12; 6M & 6F) 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 3s, while a motorized chair rotated their trunk at a frequency of 0.04Hz, 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.

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. 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. 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). 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.

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.

Prevalence of Static Balance Impairment and Associated Factors of University Student Smartphone Users with Subclinical Neck Pain: Cross-Sectional Study.

The aim of this study was to assess the prevalence of static balance impairment in university student smartphone users with subclinical neck pain and identify the associated risk factors. Because of rapid and widespread smartphones use, and the subsequent effect on neck pain in university students, it is essential to determine the prevalence of balance impairment and associated factors in this population. Simple random sampling was completed among eighty-one participants in this cross-sectional study. A self-reported questionnaire, fitted precisely for smartphone users, was used prior to clinical assessment by the Balance Error Scoring System. Both simple and multiple logistic regressions were used to analyze the prevalence of static balance impairment and associated factors. The prevalence of static balance impairment in university student smartphone users with subclinical neck pain was 74.07% (95% CI: 64.32 to 83.82). The significant risk factors were “daily smartphone use ≥ 4 h’’ (AOR: 19.24 (95% CI 4.72 to 78.48) p = 0.000), “≥4 years of smartphone use” (AOR: 5.01 (95% CI 1.12 to 22.38) p = 0.035), and “≥7 neck disability index score’’ (AOR: 12.91 (95% CI 2.24 to 74.45) p = 0.004). There was a high prevalence of static balance impairment in university smartphone users with subclinical neck pain. University student smartphone users with subclinical neck pain who met at least one of the risk factors should realize their static balance impairment.

The impact of subclinical neck pain on goal-directed upper limb movement in the horizontal plane.

Subclinical neck pain (SCNP) refers to recurrent neck pain and/or stiffness for which individuals have not yet sought treatment. Prior studies have shown that individuals with SCNP have altered cerebellar processing that exhibits an altered body schema. The cerebellum also plays a vital role in upper limb reaching movements through refining internal models and integrating sensorimotor information. However, the impact of SCNP on these processes has yet to be examined in the context of a rapid goal-directed aiming response that relies on feedforward and feedback processes to guide the limb to the target. To address this, SCNP and control participants performed goal-directed upper limb movements with the dominant and non-dominant hands using light and heavy styli in the horizontal plane. The results show greater peak accelerations in SCNP participants using the heavy stylus. However, there were no other group differences seen, possibly due to the fact that reaching behavior predominantly relies on vision such that any proprioceptive deficits seen in those with SCNP can be compensated. This study illustrates the robust compensatory nature of the CNS when performing end-effector reaching tasks, suggesting studies altering visual feedback may be needed to see the full impact of SCNP on upper limb aiming.

Influence of Neck Pain, Cervical Extensor Muscle Fatigue, and Manual Therapy on Wrist Proprioception

ObjectiveThe purpose of this study was to examine the effects of submaximal isometric neck muscle fatigue and manual therapy on wrist joint position sense (JPS) within healthy individuals and individuals with subclinical neck pain (SCNP). MethodsTwelve healthy participants and 12 participants with SCNP were recruited. Each group completed 2 sessions, with 48 hours between sessions. On day 1, both groups performed 2 wrist JPS tests using a robotic device. The tests were separated by a submaximal isometric fatigue protocol for the cervical extensor muscles (CEM). On day 2, both groups performed a wrist JPS test, followed by a cervical treatment consisting of manual therapy (SCNP) or neck rest (20 minutes, control group) and another wrist JPS test. Joint position sense was measured as the participant's ability to recreate a previously presented wrist angle. Each wrist JPS test included 12 targets, 6 into wrist flexion and 6 into wrist extension. Kinematic data from the robot established absolute, variability, and constant error. ResultsAbsolute error significantly decreased (P = .01) from baseline to post-fatigue in the SCNP group (baseline = 4.48 ± 1.58°; post-fatigue = 3.90 ± 1.45°) and increased in the control group (baseline = 3.12 ± 0.98°; post-fatigue = 3.81 ± 0.90°). The single session of manual cervical treatment significantly decreased absolute error in participants with SCNP (P = .004). ConclusionThis study demonstrated that neck pain or fatigue can lead to altered afferent input to the central nervous system and can affect wrist JPS. Our findings demonstrate that acute wrist proprioception may be improved in individuals with SCNP by a single cervical manual therapy session.

The Influence of Subclinical Neck Pain on Neurophysiological and Behavioral Measures of Multisensory Integration.

Multisensory integration (MSI) is necessary for the efficient execution of many everyday tasks. Alterations in sensorimotor integration (SMI) have been observed in individuals with subclinical neck pain (SCNP). Altered audiovisual MSI has previously been demonstrated in this population using performance measures, such as reaction time. However, neurophysiological techniques have not been combined with performance measures in the SCNP population to determine differences in neural processing that may contribute to these behavioral characteristics. Electroencephalography (EEG) event-related potentials (ERPs) have been successfully used in recent MSI studies to show differences in neural processing between different clinical populations. This study combined behavioral and ERP measures to characterize MSI differences between healthy and SCNP groups. EEG was recorded as 24 participants performed 8 blocks of a simple reaction time (RT) MSI task, with each block consisting of 34 auditory (A), visual (V), and audiovisual (AV) trials. Participants responded to the stimuli by pressing a response key. Both groups responded fastest to the AV condition. The healthy group demonstrated significantly faster RTs for the AV and V conditions. There were significant group differences in neural activity from 100–140 ms post-stimulus onset, with the control group demonstrating greater MSI. Differences in brain activity and RT between individuals with SCNP and a control group indicate neurophysiological alterations in how individuals with SCNP process audiovisual stimuli. This suggests that SCNP alters MSI. This study presents novel EEG findings that demonstrate MSI differences in a group of individuals with SCNP.

Intra and Inter-Rater Reliability for Deep Neck Flexor and Neck Extensor Muscle Endurance Tests in Subjects with and without Subclinical Neck Pain

Abstract Purpose Deep neck flexor (DNF) and neck extensor (NE) muscle endurance tests are a part of standard assessment procedure in routine physical therapy practice and these tests needs to be reliable. Materials and Methods Intra-rater (between-day) and inter-rater (within-day) reliability was assessed for 2 neck muscle endurance tests in 26 subclinical neck pain and 31 normal subjects by 2 blinded assessors. The tests conducted included 1) DNF endurance test performed in supine and 2) NE muscle endurance test performed in prone position. Results and discussion The Intra-rater and inter-rater reliability was determined by means of Intra Class Correlation (ICC), with 95% confidence intervals. The intra rater reliability testing showed good agreement for both DNF (ICC=0.76 and 0.78) and NE muscle endurance (ICC=0.75 and 0.76) tests. Meanwhile, the inter-rater reliability showed moderate to good agreement for both DNF (ICC – 0.58 and 0.61) and NE muscle endurance tests (ICC – 0.57 and 0.74) in subjects with subclinical neck pain. Subclinical neck pain subjects had a significantly lower endurance holding times compared to normal (p&lt;0.001). Conclusion The intra and inter rater reliability ranged from moderate to good agreement. Neck flexor and extensor muscle endurance can be measured reliably in a clinical setup in subjects with subclinical neck pain.

Increased Voluntary Activation of the Elbow Flexors Following a Single Session of Spinal Manipulation in a Subclinical Neck Pain Population.

To investigate the effects of a single session of spinal manipulation (SM) on voluntary activation of the elbow flexors in participants with subclinical neck pain using an interpolated twitch technique with transcranial magnetic stimulation (TMS), eighteen volunteers with subclinical neck pain participated in this randomized crossover trial. TMS was delivered during elbow flexion contractions at 50%, 75% and 100% of maximum voluntary contraction (MVC) before and after SM or control intervention. The amplitude of the superimposed twitches evoked during voluntary contractions was recorded and voluntary activation was calculated using a regression analysis. Dependent variables were analyzed with two-way (intervention × time) repeated measures ANOVAs. Significant intervention effects for SM compared to passive movement control were observed for elbow flexion MVC (p = 0.04), the amplitude of superimposed twitch (p = 0.04), and voluntary activation of elbow flexors (p =0.03). Significant within-group post-intervention changes were observed for the superimposed twitch (mean group decrease of 20.9%, p < 0.01) and voluntary activation (mean group increase of 3.0%, p < 0.01) following SM. No other significant within-group changes were observed. Voluntary activation of the elbow flexors increased immediately after one session of spinal manipulation in participants with subclinical neck pain. A decrease in the amplitude of superimposed twitch during elbow flexion MVC following spinal manipulation suggests a facilitation of motor cortical output.

Pressure pain thresholds in university students with undertreated neck pain: comparison with asymptomatic individuals, reliability and measurement error

Aims: The aims of this study were to compare pressure pain thresholds (PPTs) between university students with and without undertreated neck pain and to assess intra-rater reliability and measurement error.Methods: University students with sub-clinical neck pain (n = 25) and age- and sex-matched pain-free participants (n = 25) were assessed for pain characteristics (location, intensity, frequency and duration) and had their PPTs measured bilaterally at C5–C6 zygapophyseal joint and upper trapezius. PPT measurements were taken three times at each site.Results: PPT measurements showed substantial to almost perfect intra-rater reliability (ICC between 0.79 and 0.95) but high minimal detectable differences (between 5.29 N/cm2 and 9.20 N/cm2). PPTs values were significantly lower in the group of participants with sub-clinical neck pain compared with the asymptomatic group (p<.05) for three out of the four sites of measurement.Conclusions: PPT measurements may be relevant to distinguish between individuals or groups but may be of limited value when assessing changes over time in the same individual with undertreated neck pain.

Forward head posture is associated with pressure pain threshold and neck pain duration in university students with subclinical neck pain

Objective: The aims of this study are to investigate the association between: (i) forward head posture (FHP) and pressure pain thresholds (PPTs); (ii) FHP and maladaptive cognitive processes; and (iii) FHP and neck pain characteristics in university students with subclinical neck pain.Materials/methods: A total of 140 university students, 90 asymptomatic and 50 with subclinical neck pain, entered the study. Demographic data, anthropometric data, FHP, and PPTs were collected for both groups. In addition, pain characteristics, pain catastrophizing, and fear of movement were assessed for participants with neck pain. FHP was characterized by the angle between C7, the tragus of the ear, and the horizontal line. Correlation analysis and multivariate regression analysis were conducted.Results: Participants with subclinical neck pain showed significantly lower PPTs than participants without neck pain (p < .05), but similar FHP (p > .05). No significant association was found between FHP and PPTs in the asymptomatic group. In the group of participants with subclinical neck pain, PPTs at the right trapezius and neck pain duration explained 19% of the variance of FHP (R2 = 0.23; adjusted R2 = 0.19; p < .05).Conclusion: This study suggests that FHP is not associated with PPTs in asymptomatic university students. In university students with subclinical neck pain, increased FHP was associated with right trapezius hypoalgesia and with neck pain of shorter duration. These findings are in contrast with current assumptions on the association between neck pain and FHP.

Association of Subclinical Neck Pain With Altered Multisensory Integration at Baseline and 4-Week Follow-up Relative to Asymptomatic Controls

ObjectiveThe purpose of this study was to test whether people with subclinical neck pain (SCNP) had altered visual, auditory, and multisensory response times, and whether these findings were consistent over time. MethodsTwenty-five volunteers (12 SCNP and 13 asymptomatic controls) were recruited from a Canadian university student population. A 2-alternative forced-choice discrimination task with multisensory redundancy was used to measure response times to the presentation of visual (color filled circles), auditory (verbalization of the color words, eg, red or blue), and multisensory (simultaneous audiovisual) stimuli at baseline and 4 weeks later. ResultsThe SCNP group was slower at both visual and multisensory tasks (P = .046, P = .020, respectively), with no change over 4 weeks. Auditory response times improved slightly but significantly after 4 weeks (P = .050) with no group difference. ConclusionsThis is the first study to report that people with SCNP have slower visual and multisensory response times than asymptomatic individuals. These differences persist over 4 weeks, suggesting that the multisensory technique is reliable and that these differences in the SCNP group do not improve on their own in the absence of treatment.

The effects of subclinical neck pain on sensorimotor integration following a complex motor pursuit task.

Recurrent subclinical neck pain (SCNP) may be associated with neural plastic changes in sensory processing and sensorimotor integration (SMI); however, its impact on motor learning has not been investigated. The aim of this study was to investigate whether SCNP alters neural markers of SMI during a complex motor acquisition task as compared to a healthy control group. Peripheral N9, spinal N13, brainstem N18, and cortical N20, P25, N24 and N30 early somatosensory evoked potentials (SEPs) were recorded following median nerve stimulation for 24 participants (12 control and 12 SCNP) before and after a 10-min tracing motor task intervention. Retention was assessed 24-48h later. Significant amplitude differences were observed for both N18 and N24 SEP waveforms between groups, indicating there may be a difference in SMI due to altered afferent input as a result of SCNP. Accuracy increased significantly for both groups post-motor training; however, at retention only the control group showed an additional increase in accuracy. Both N18 and N24 SEP peaks are linked with cerebellar pathways, suggesting that SCNP impacts these connections. Significant correlations between these peaks and performance data were also seen. The differential changes in neurophysiological markers of SMI seen in SCNP suggest that SEPs have the potential to be used as an early screening tool for those at risk of having maladaptive neural plastic changes in response to motor training as a result of SCNP.

Neck muscle fatigue differentially alters scapular and humeral kinematics during humeral elevation in subclinical neck pain participants versus healthy controls

BackgroundScapular orientation is highly dependent on axioscapular muscle function. This study examined the impact of neck muscle fatigue on scapular and humeral kinematics in participants with and without subclinical neck pain (SCNP) during humeral elevation. MethodsTen SCNP and 10 control participants performed three unconstrained trials of dominant arm humeral elevation in the scapular plane to approximately 120 degrees before and after neck extensor muscle fatigue. Three-dimensional scapular and humeral kinematics were measured during the humeral elevation trials. ResultsHumeral elevation plane angle showed a significant interaction between groups (SCNP vs controls) and trial (pre- vs post-fatigue) (p=0.001). Controls began the unconstrained humeral elevation task after fatigue in a more abducted position, (p=0.002). Significant baseline differences in scapular rotation existed between the two groups (Posterior/Anterior tilt, p=0.04; Internal/External Rotation, p=0.001). DiscussionSCNP contributed to altered scapular kinematics. Neck muscle fatigue influenced humeral kinematics in controls but not the SCNP group; suggesting that altered scapular motor control in the SCNP group resulted in an impaired adaption further to the neck muscle fatigue.

Neck Flexor and Extensor Muscle Endurance in Subclinical Neck Pain: Intrarater Reliability, Standard Error of Measurement, Minimal Detectable Change, and Comparison With Asymptomatic Participants in a University Student Population

ObjectiveThe aims of this study were to assess intrarater reliability and to calculate the standard error of measurement (SEM) and minimal detectable change (MDC) for deep neck flexor and neck extensor muscle endurance tests, and compare the results between individuals with and without subclinical neck pain. MethodsParticipants were students of the University of Aveiro reporting subclinical neck pain and asymptomatic participants matched for sex and age to the neck pain group. Data on endurance capacity of the deep neck flexors and neck extensors were collected by a blinded assessor using the deep neck flexor endurance test and the extensor endurance test, respectively. Intraclass correlation coefficients (ICCs), SEM, and MDC were calculated for measurements taken within a session by the same assessor. Differences between groups for endurance capacity were investigated using a Mann-Whitney U test. ResultsThe deep neck flexor endurance test (ICC = 0.71; SEM = 6.91 seconds; MDC = 19.15 seconds) and neck extensor endurance test (ICC = 0.73; SEM = 9.84 minutes; MDC = 2.34 minutes) are reliable. No significant differences were found between participants with and without neck pain for both tests of muscle endurance (P > .05). ConclusionThe endurance capacity of the deep neck flexors and neck extensors can be reliably measured in participants with subclinical neck pain. However, the wide SEM and MDC might limit the sensitivity of these tests.

Influence of Subclinical Neck Pain on the Ability to Perform a Mental Rotation Task: A 4-Week Longitudinal Study With a Healthy Control Group Comparison

ObjectiveMental rotation of objects and the frame of reference of those objects are critical for executing correct and skillful movements and are important for object recognition, spatial navigation, and movement planning. The purpose of this longitudinal study was to compare the mental rotation ability of those with subclinical neck pain (SCNP) to healthy controls at baseline and after 4 weeks. MethodsTwenty-six volunteers (13 SCNP and 12 healthy controls) were recruited from a university student population. Subclinical neck pain participants had scores of mild to moderate on the Chronic Pain Grade Scale, and controls had minimal or no pain. For the mental rotation task, participants were presented with an object (letter “R”) on a computer screen presented randomly in either normal or backwards parity at various orientations (0°, 45°, 90°, 135°, 180°, 225°, 270°, and 315°). Participants indicated the object's parity by pressing “N” for normal or “B” for backwards. Each orientation for normal and backward parities was presented 5 times, and the average response time for all letter presentations was calculated for each participant, at baseline and 4 weeks later. ResultsBoth groups had overall improved response times from baseline to 4 weeks. Healthy participants had significantly improved response times compared to SCNP, both at baseline (P < .05) and 4 weeks (P < .05). ConclusionsHealthy participants performed better than the SCNP group at both time points. Subclinical neck pain may impair the ability to perform a complex mental rotation task involving cerebellar connections, possibly due to altered body schema.

Neck muscle fatigue alters the cervical flexion relaxation ratio in sub-clinical neck pain patients

BackgroundThe cervical flexion relaxation ratio is lower in neck pain patients compared to healthy controls. Fatigue modulates the onset and offset angles of the silent period in both the lumbar and cervical spine in healthy individuals; however, this response has not been studied with neck pain patients. The purpose of this study was to determine if cervical extensor fatigue would alter the parameters of the cervical flexion relaxation more in a neck pain group than a healthy control group. MethodsThirteen healthy and twelve neck pain patients participated. Cervical extensor activity was examined bilaterally and kinematics of the neck and head were collected. An isometric, repetitive neck extension task at 70% of maximum elicited fatigue. Participants performed 3 trials of maximal cervical flexion both pre and post fatigue. FindingsThe healthy controls and neck pain groups fatigued after 56 (41) and 39 (31) repetitions, respectively. There was a significant interaction effect for the flexion relaxation ratio between the control and neck pain groups from pre to post fatigue trials (F1,96=22.67, P=0.0001), but not for onset and offset angles (F1, 96=0.017, P=0.897), although the onset and offset angles did decrease significantly for both groups following fatigue (F1,96=9.26, P=0.002). InterpretationIndividuals with mild to moderate neck pain have significant differences in their neuromuscular control relative to controls, experienced myoelectric fatigue with fewer repetitions in a shorter time, had a lower cervical flexion relaxation ratio at baseline and had an inability to decrease this ratio further in response to fatigue.

The impact of cervical manipulation on heart rate variability.

Heart Rate variability (HRV) is the inter-beat variability in heart rate and is moderated by the balance of sympathetic and parasympathetic divisions of the autonomic nervous system. Electrocardiography (ECG) can be utilized to obtain Low frequency (LF) to high frequency (HF) ratios that represent sympathetic to parasympathetic response, respectively and these ratios may be increased in people with chronic pain. Spinal manipulation is often used to manage musculoskeletal disorders such as neck pain. This study assesses the influence of cervical manipulation on HRV using LF/HF ratio. Ten subjects without neck pain formed the control condition and passive head movement (PHM) condition during which their head was flexed, extended and rotated. Ten subjects with subclinical neck pain underwent the same conditions. A separate session was performed for an actual manipulation. LabChart™ software was utilized to collect and analyze five minute pre and post R-R intervals. Repeated measures of ANOVA demonstrated significant interaction effect on HRV (F (1, 18) = 6.841, p = 0.018) following manipulation vs. PHM. Subsequent analysis showed a significant decrease in the ratio during manipulation condition (p = 0.0316), that was not seen in any other conditions, suggesting a significant autonomic nervous system alteration. This study may lead to new techniques to assess the effectiveness of various treatment interventions.

Effect of Isometric Exercises and Proprioceptive Exercises in IT Professionals Suffering from Sub Clinical Neck Pain

Objective: To study the effects of isometric and proprioceptive exercises in IT professionals suffering from subclinical neck pain. Methodology: 30 subjects within age group of 18-40 yrs both males and females from IT companies with subclinical neck pain participated in the study. Subjects who were working for a minimum of 6 hours /day or 30 hours/ week and with the NDI score in between range of 5-14 were included in the study. Subjects were excluded if they had any other musculoskeletal, vertebro basilar insufficiency symptoms and neurological disorders, had undergone cervical spine surgery or were undergoing treatment at the time of testing. Improvements were noted on VAS score, NDI score, extensor muscle strength measurement and proprioception i.e. joint position sense. Results: Significant differences were observed within two groups i.e. group B given postural training and strength training exercises as well as group C given postural training, strength training and proprioceptive training exercises compared to group A given postural training exercises only. On intergroup analysis between groups B and C no significant difference was found. Conclusion: Strength training program with postural correction tips is equally effective as combination of strength and proprioceptive training group in improving pain, disability, muscle strength and proprioception.