Objective To determine whether dry needling of an active myofascial trigger point (MTrP) reduces pain and alters the status of the trigger point to either a non-spontaneously tender nodule or its resolution. Design A prospective, non-randomized, controlled interventional clinical study Setting University campus Participants Fifty-six subjects with neck or shoulder girdle pain > 3 months duration and active MTrPs were recruited from a campus-wide, volunteer sample. Fifty-two completed the study (23 male/33 female) with mean age of 35.8 years. Interventions Three weekly dry needling treatments of a single active MTrP Main Outcome Measures Primary Outcomes: Baseline and post treatment evaluations of pain using the verbal analogue scale, the Brief Pain Inventory and the status of the MTrP as determined by digital palpation. Trigger points were rated: active (spontaneously painful), latent (requiring palpation to reproduce the characteristic pain) and resolved (no palpable nodule). Secondary Outcomes: Profile of Mood States, Oswestry Disability Index, Short Form 36, Cervical Range of Motion. Results Primary outcomes: 41 subjects had a change in trigger point status from active to latent or resolved; and 11 had no change (p < .001). Reduction in all pain scores was significant (p<.001). Secondary outcomes: significant improvement in post-treatment cervical rotational asymmetry in subjects with unilateral/bilateral MTrPs (p=.001, p=21, respectively); in pain pressure threshold in subjects with unilateral/bilateral MTrPs, (p=.006, p=.012), respectively; improvement in the SF-36 mental health and physical functioning subscales (p=.019, p=.03) respectively; decrease in the Oswestry disability scale (p=.003). Conclusions Dry needling reduces pain and changes MTrP status. Change in trigger point status is associated with a statistically and clinically significant reduction in pain. Reduction in pain is associated with improved mood, function and level of disability.

Objectives Our objectives were to develop a new, efficient, and easy-to-administer approach to ultrasound elastography and assess its ability to provide quantitative characterization of viscoelastic properties of skeletal muscle in an outpatient clinical environment. We sought to show its validity and clinical utility in assessing myofascial trigger points, which are associated with myofascial pain syndrome. Methods Ultrasound imaging was performed while the muscle was externally vibrated at frequencies in the range of 60 to 200 Hz using a handheld vibrator. The spatial gradient of the vibration phase yielded the shear wave speed, which is related to the viscoelastic properties of tissue. The method was validated using a calibrated experimental phantom, the biceps brachii muscle in healthy volunteers (n = 6), and the upper trapezius muscle in symptomatic patients with axial neck pain (n = 13) and asymptomatic (pain-free) control participants (n = 9). Results Using the experimental phantom, our method was able to quantitatively measure the shear moduli with error rates of less than 20%. The mean shear modulus ± SD in the normal biceps brachii measured 12.5 ± 3.4 kPa, within the range of published values using more sophisticated methods. Shear wave speeds in active myofascial trigger points and the surrounding muscle tissue were significantly higher than those in normal tissue at high frequency excitations (>100 Hz; P < .05). Conclusions Off-the-shelf office-based equipment can be used to quantitatively characterize skeletal muscle viscoelastic properties with estimates comparable to those using more sophisticated methods. Our preliminary results using this method indicate that patients with spontaneous neck pain and symptomatic myofascial trigger points have increased tissue heterogeneity at the trigger point site and the surrounding muscle tissue.

Objective To determine whether standard evaluations of pain distinguish subjects with no pain from those with myofascial pain syndromes (MPS) and active trigger points (MTrPs); and to assess whether self-reports of mood, function and health-related quality of life differ between these groups. Design Prospective, descriptive study. Setting University Patients Adults with and without neck pain Methods We evaluated adults with MPS and active (painful) MTrPs and those without pain. Subjects in the “Active” (‘A’) group had at least one active MTrP with spontaneous pain which was persistent, lasted more than 3 months and had characteristic pain on palpation. Subjects in the “No pain” (‘Np’) group had no spontaneous pain. However, some had discomfort on MTrP palpation (latent MTrP) while others in the Np group had no discomfort on palpation of nodules or had no nodules. Outcome Measures Each participant underwent range of motion (ROM) measurement, 10-point manual muscle test, and manual and algometric palpation. The latter determined the pain/pressure threshold using an algometer of 4 pre-determined anatomical sites along the upper trapezius. Participants rated pain using a verbal analogue scale (0–10); completed the Brief Pain Inventory and Oswestry Disability Scale (ODS), which included a sleep sub-scale; Short Form 36(SF36) and the Profile of Mood States (POMS). Results here were 24 in the ‘A’ group (mean 36 yrs, 16 women) and 26 in the ‘Np’ group (mean 26 yrs, 12 women). Subjects in group ‘A’ differed from ‘Np’ in number of latent MTrPs (p=.0062); asymmetrical cervical ROM (p=.01 side bending and p=.002 rotation); in all pain reports (p<.0001); algometry (p<.03); POMS (p<.038); SF36 (p<.01) and ODS (p<.0001). Conclusion A systematic musculoskeletal evaluation of people with MPS reliably distinguishes them from subjects with no pain. The two groups are significantly different in their physical findings and self-reports of pain, sleep disturbance, disability, health status and mood. These findings support the view that a “local” pain syndrome has significant associations with mood, health-related quality of life and function..

Myofascial trigger points (MTrPs) are palpable, tender nodules in taut bands of skeletal muscle that are painful on compression. MTrPs are characteristic findings in myofascial pain syndrome (MPS). The role of MTrPs in the pathophysiology of MPS is unknown. Localization, diagnosis, and clinical outcome measures of painful MTrPs can be improved by objectively characterizing and quantitatively measuring their properties. The goal of this study was to evaluate whether ultrasound imaging and elastography can differentiate symptomatic (active) MTrPs from normal muscle. Patients with chronic (>3 months) neck pain with spontaneously painful, palpable (i.e., active) MTrPs and healthy volunteers without spontaneous pain (having palpably normal muscle tissue) were recruited for this study. The upper trapezius muscles in all subjects were imaged, and the echotexture was analyzed using entropy filtering of B-mode images. Vibration elastography was performed by vibrating the muscle externally at 100 Hz. Color Doppler variance imaging was used to quantify the regions of color deficit exhibiting low vibration amplitude. The imaging measures were compared against the clinical findings of a standardized physical exam. We found that sites with active MTrPs (n = 14) have significantly lower entropy (p < 0.05) and significantly larger nonvibrating regions (p < 0.05) during vibration elastography compared with normal, uninvolved muscle (n = 15). A combination of both entropy analysis and vibration elastography yielded 69% sensitivity and 81% specificity in discriminating active MTrPs from normal muscle. These results suggest that active MTrPs have more homogeneous texture and heterogeneous stiffness when compared with normal, unaffected muscle. Our methods enabled us to improve the imaging contrast between suspected MTrPs and surrounding muscle. Our results indicate that in subjects with chronic neck pain and active MTrPs, the abnormalities are not confined to discrete isolated nodules but instead affect the milieu of the muscle surrounding palpable MTrPs. With further refinement, ultrasound imaging can be a promising objective method for characterizing soft tissue abnormalities associated with active MTrPs and elucidating the role of MTrPs in the pathophysiology of MPS.

The underwater acoustic field is an important ecological element for many aquatic animals. This research examines the soundscape of a critically endangered Indo-Pacific humpback dolphin population in the shallow water environment off the west coast of Taiwan. Underwater acoustic recordings were conducted between late spring and late fall in 2012 at Yunlin (YL), which is close to a shipping lane, and Waisanding (WS), which is relatively pristine. Site-specific analyses were performed on the dynamics of the temporal and spectral acoustic characteristics for both locations. The results highlight the dynamics of the soundscape in two major octave bands: 150-300 Hz and 1.2-2.4 kHz. The acoustic energy in the former frequency band is mainly associated with passing container vessels near YL, while the latter frequency band is from sonic fish chorus at nighttime in both recording sites. In addition, large variation of low frequency acoustic energy throughout the study period was noticed at WS, where the water depths ranged between 1.5 and 4.5 m depending on tidal cycle. This phenomenon suggests that besides certain sound sources in the environment, the coastal soundscape may also be influenced by its local bathymetry and the dynamics of the physical environment.