Does vibration frequency and location influence the effect of neck muscle vibration on postural sway? A cross-sectional study in asymptomatic participants

INTRODUCTION

Postural control is of utmost importance for human functioning. Cervical proprioception is crucial for balance control. Therefore, any change to it can lead to balance problems. Previous studies used neck vibration to change cervical proprioception and showed changes in postural control, but it remains unknown which vibration frequency or location causes the most significant effect. Therefore, this study aimed to investigate the effect of different vibration frequencies and locations on postural sway and to serve as future research protocol guidance.

METHODS

Seventeen healthy young participants were included in the study. We compared postural sway without vibration to postural sway with six different combinations of vibration frequency (80, 100, and 150 Hz) and location (dorsal neck muscles and sternocleidomastoid). Postural sway was evaluated using a force platform. The mean center of pressure (CoP) displacement, the root mean square (RMS), and the mean velocity in the anteroposterior and mediolateral direction were calculated, as well as the sway area. The aligned rank transform tool and a three-way repeated measures ANOVA were used to identify significant differences in postural sway variables.

RESULTS

Neck vibration caused a significant increase in all postural sway variables (p < 0.001). Neither the vibration frequency (p > 0.34) nor location (p > 0.29) nor the interaction of both (p > 0.30) influenced the magnitude of the change in postural sway measured during vibration.

CONCLUSION

Neck muscle vibration significantly changes CoP displacement, mean velocity, RMS, and area. However, we investigated and found that there were no significant differences between the different combinations of vibration frequency and location.

Prognostic indicators for decrease in tinnitus severity after cervical physical therapy in patients with cervicogenic somatic tinnitus

BACKGROUND

Tinnitus can be related to many different aetiologies such as hearing loss or a noise trauma, but it can also be related to the somatosensory system of the cervical spine, called cervicogenic somatic tinnitus(CST). Recently, a positive effect of multi-modal cervical physical therapy on tinnitus severity in patients with CST was demonstrated. To date however, the outcome of the intervention cannot be predicted.

OBJECTIVE

To identify prognostic indicators for decrease in tinnitus severity after cervical physical therapy in patients with CST.

PATIENTS

Patients with moderate to severe subjective tinnitus (Tinnitus Functional Index(TFI):25-90points) and neck complaints (Neck Bournemouth Questionnaire(NBQ) > 14points).

INTERVENTION

All patients received multimodal cervical physical therapy for 6 weeks (12 sessions). This physical therapy contained a combination of manual mobilizations and exercises of the cervical spine.

MEASUREMENTS

TFI and NBQ-scores were documented at baseline, after treatment and after a 6-weeks follow-up period. Impairments in cervical spine mobility and muscle function were identified at baseline and after 6-weeks follow-up.

RESULTS

Patients with co-varying (increasing or decreasing simultaneously) tinnitus and neck complaints had significantly lower TFI-scores after treatment (p = 0.001) and follow-up (p = 0.03). The presence of this co-variation and a combination of low pitched tinnitus and increasing tinnitus during inadequate cervical spine postures are prognostic indicators for a decrease in TFI-scores after cervical physical therapy (adjusted R² = 0.357).

CONCLUSION

Patients who experience a decrease in tinnitus annoyance from cervical physical therapy are those with co-varying tinnitus and neck complaints and those with a combination of low-pitched tinnitus and increasing tinnitus during inadequate cervical spine postures.

Lack of Impairment of Kinaesthetic Sensibility in Cervicogenic Headache Patients

To compare the cervical kinaesthetic sensibility of cervicogenic headache (CEH) patients and asymptomatic controls, the head repositioning accuracy of 10 CEH patients and 23 asymptomatic controls was measured. Should an impaired kinaesthetic sensibility be demonstrated, its assessment could be of diagnostic value in the evaluation of patients with suspected CEH. Additionally, specific exercises to improve cervical kinaesthesia could be prescribed. Kinaesthetic sensibility was assessed using a head repositioning task: subjects were asked to relocate their heads as accurately as possible to a previously memorized head position following an active movement (flexion, extension and left and right rotations). The repositioning error was registered using a validated magnetic tracking device (Flock of Birds). No significant differences were found between the asymptomatic controls and the CEH patients (independent-samples T-test, P < 0.05). We conclude that cervical kinaesthetic sensibility is not impaired in non-traumatic CEH. The use of kinaesthetic assessment and treatment in this patient group seems to be limited.