Balance Performance in Patients with Whiplash Associated Disorders and Patients with Prolonged Musculoskeletal Disorders

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

OBJECTIVE

The 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.

METHODS

Twenty-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.

RESULTS

The 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.

CONCLUSIONS

This 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.

Development of the movement domain in the global body examination

The purpose of this study was to develop a new Movement domain, based on 16 items from the Global Physiotherapy Examination-52 (GPE-52) and 18 items from the Comprehensive Body Examination (CBE). Furthermore, we examined how well the new domain and its scales would discriminate between healthy individuals and different groups of patients, compared to the original methods. Two physiotherapists, each using one method, independently examined 132 individuals (34 healthy, 32 with localized pain, 32 with generalized pain, and 34 with psychoses). The number of items was reduced by means of correlational and exploratory factor analysis. Internal consistency was examined with Cronbach's alpha. For examination of discriminative validity, Mann-Whitney U-test and Area under the Curve (AUC) were used. The initial 34 items were reduced to two subscales with 13 items: one for range of movement and balance and one for flexibility. Cronbach's alpha was 0.84 and 0.87 for the two subscales. The new subscales showed very good to excellent discriminating ability between healthy persons and the different patient groups (p < 0.001; AUC 0.82-0.95). Furthermore, patients with localized pain had significantly less movement aberrations than the other patient groups. The new Movement domain had fewer items than the GPE-52 and CBE, without losing discriminative validity.

Altered central integration of dual somatosensory input after cervical spine manipulation

OBJECTIVE

The aim of the current study was to investigate changes in the intrinsic inhibitory interactions within the somatosensory system subsequent to a session of spinal manipulation of dysfunctional cervical joints.

METHOD

Dual peripheral nerve stimulation somatosensory evoked potential (SEP) ratio technique was used in 13 subjects with a history of reoccurring neck stiffness and/or neck pain but no acute symptoms at the time of the study. Somatosensory evoked potentials were recorded after median and ulnar nerve stimulation at the wrist (1 millisecond square wave pulse, 2.47 Hz, 1 x motor threshold). The SEP ratios were calculated for the N9, N11, N13, P14-18, N20-P25, and P22-N30 peak complexes from SEP amplitudes obtained from simultaneous median and ulnar (MU) stimulation divided by the arithmetic sum of SEPs obtained from individual stimulation of the median (M) and ulnar (U) nerves.

RESULTS

There was a significant decrease in the MU/M + U ratio for the cortical P22-N30 SEP component after chiropractic manipulation of the cervical spine. The P22-N30 cortical ratio change appears to be due to an increased ability to suppress the dual input as there was also a significant decrease in the amplitude of the MU recordings for the same cortical SEP peak (P22-N30) after the manipulations. No changes were observed after a control intervention.

CONCLUSION

This study suggests that cervical spine manipulation may alter cortical integration of dual somatosensory input. These findings may help to elucidate the mechanisms responsible for the effective relief of pain and restoration of functional ability documented after spinal manipulation treatment.

Head repositioning accuracy and posturography related to cervical facet nerve blockade and spinal manipulative therapy in healthy volunteers: a time series study

OBJECTIVE

The aim of the study was to investigate if changes in head repositioning accuracy (HRA), and standing balance could be evoked by unilateral facet nerve blockade (FNB) or spinal manipulative therapy (SMT).

METHODS

This time series research study (n = 6) was chosen because of the viability of the experiment, sample characteristics, and small sample size. Cervical proprioceptive functions were assessed by exploring HRA and static posture by computerized posturography. All participants were subjected to 2 interventions, unilateral FNB using local anesthetic and SMT.

RESULTS

No significant trends were seen in the subjects over the period of the study. All measurements were taken approximately 3 weeks apart. Visually, it was detected that most of subjects appeared to be greatly affected by the FNB, thus, increasing their deviation from the center point of measurement in extension and flexion movements. When comparing the changes with respect to the baseline after SMT, all subjects showed some differences, though there was a great deal of variation between the subjects. These trends were also seen when comparing the changes from baseline measurements to those after FNB.

CONCLUSIONS

Data from this time series research design suggest there was no uniform response to unilateral FNB or to SMT. However, differences indicate that there may be important effects of unilateral FNBs for some of the HRA aspects measured. Balance testing using computerized posturography did not show clear differences between baseline assessments and interventions. A future larger clinical study to detect changes in HRA evoked by unilateral FNB or SMT appears feasible.

Cervicocephalic kinesthetic sensibility and postural balance in patients with nontraumatic chronic neck pain--a pilot study

Background

Although cervical pain is widespread, most victims are only mildly and occasionally affected. A minority, however, suffer chronic pain and/or functional impairments. Although there is abundant literature regarding nontraumatic neck pain, little focuses on diagnostic criteria. During the last decade, research on neck pain has been designed to evaluate underlying pathophysiological mechanisms, without noteworthy success. Independent researchers have investigated postural balance and cervicocephalic kinesthetic sensibility among patients with chronic neck pain, and have (in most cases) concluded the source of the problem is a reduced ability in the neck's proprioceptive system. Here, we investigated cervicocephalic kinesthetic sensibility and postural balance among patients with nontraumatic chronic neck pain.

Methods

Ours was a two-group, observational pilot study of patients with complaints of continuous neck pain during the 3 months prior to recruitment. Thirteen patients with chronic neck pain of nontraumatic origin were recruited from an institutional outpatient clinic. Sixteen healthy persons were recruited as a control group. Cervicocephalic kinesthetic sensibility was assessed by exploring head repositioning accuracy and postural balance was measured with computerized static posturography.

Results

Parameters of cervicocephalic kinesthetic sensibility were not reduced. However, in one of six test movements (flexion), global repositioning errors were significantly larger in the experimental group than in the control group (p < .05). Measurements did not demonstrate any general impaired postural balance, and varied substantially among participants in both groups.

Conclusion

In patients with nontraumatic chronic neck pain, we found statistically significant global repositioning errors in only one of six test movements. In this cohort, we found no evidence of impaired postural balance.

Head repositioning accuracy and computerized static posturography are imperfect measures of functional proprioceptive impairments. Validity of (and procedures for using) these instruments demand further investigation.

Trial registration

Current Controlled Trials ISRCTN96873990

Sensorimotor function and dizziness in neck pain: implications for assessment and management

SYNOPSIS

The term sensorimotor describes all the afferent, efferent, and central integration and processing components involved in maintaining stability in the postural control system through intrinsic motor-control properties. The scope of this paper is to highlight the sensorimotor deficits that can arise from altered cervical afferent input. From a clinical orthopaedic perspective, the peripheral mechanoreceptors are the most important in functional joint stability; but in the cervical region they are also important for postural stability, as well as head and eye movement control. Consequently, conventional musculoskeletal intervention approaches may be sufficient only for patients with neck pain and minimal sensorimotor proprioceptive disturbances. Clinical experience and research indicates that significant sensorimotor cervical proprioceptive disturbances might be an important factor in the maintenance, recurrence, or progression of various symptoms in some patients with neck pain. In these cases, more specific and novel treatment methods are needed which progressively address neck position and movement sense, as well as cervicogenic oculomotor disturbances, postural stability, and cervicogenic dizziness. In this commentary we review the most relevant theoretical and practical knowledge on this matter and implications for clinical assessment and management, and we propose future directions for research.

LEVEL OF EVIDENCE

Level 5.

Altered sensorimotor integration with cervical spine manipulation

OBJECTIVE

This study investigates changes in the intrinsic inhibitory and facilitatory interactions within the sensorimotor cortex subsequent to a single session of cervical spine manipulation using single- and paired-pulse transcranial magnetic stimulation protocols.

METHOD

Twelve subjects with a history of reoccurring neck pain participated in this study. Short interval intracortical inhibition, short interval intracortical facilitation (SICF), motor evoked potentials, and cortical silent periods (CSPs) were recorded from the abductor pollicis brevis and the extensor indices proprios muscles of the dominant limb after single- and paired-pulse transcranial magnetic stimulation of the contralateral motor cortex. The experimental measures were recorded before and after spinal manipulation of dysfunctional cervical joints, and on a different day after passive head movement. To assess spinal excitability, F wave persistence and amplitudes were recorded after median nerve stimulation at the wrist.

RESULTS

After cervical manipulations, there was an increase in SICF, a decrease in short interval intracortical inhibition, and a shortening of the CSP in abductor pollicis brevis. The opposite effect was observed in extensor indices proprios, with a decrease in SICF and a lengthening of the CSP. No motor evoked potentials or F wave response alterations were observed, and no changes were observed after the control condition.

CONCLUSION

Spinal manipulation of dysfunctional cervical joints may alter specific central corticomotor facilitatory and inhibitory neural processing and cortical motor control of 2 upper limb muscles in a muscle-specific manner. This suggests that spinal manipulation may alter sensorimotor integration. These findings may help elucidate mechanisms responsible for the effective relief of pain and restoration of functional ability documented after spinal manipulation.