Repetitive motion in perception of tactile sensation in the fingers of string players

Effective assessments to identify overuse injuries in unaffected limbs of persons with unilateral upper limb amputations

STUDY DESIGN

Cross-sectional study.

INTRODUCTION

Overuse injuries (OI) present major health problems and oftentimes, permanent disability. Persons with unilateral upper limb diagnoses, such as amputation, are at-risk for developing OI in their unaffected limbs. Measures to identify high-risk populations are needed.

PURPOSE OF THE STUDY

Scores on 6 OI-assessments were compared for persons with unilateral upper limb amputations (UULA) and healthy participants. Cutoff values were proposed.

METHODS

Sixty-two persons with UULA and 62 healthy controls completed this study. Scores for hand volume (HV), visual analogue scale (VAS), multi-site Semmes Weinstein Monofilament for median and ulnar nerves (SWM-M/SWM-U), torque range of motion for wrist/finger extension and flexion (TROM-E/TROM-F), intrinsic tightness (IT), and differential flexor tendon gliding (DFTG) were collected before and after 15 minutes of repetitive and resistive exercise. When analyzing collected data, descriptive statistics, and ANOVA were used to identify differences between groups. Receiver operating characteristic curves (ROC), area under the curve (AUC), sensitivity, and specificity were calculated to determine acceptable cutoff scores. Cutoff values with significant AUC ≥ 0.60 and sensitivity ≥ 0.80 were accepted.

RESULTS

Statistically significant differences were found between HV by gender in both pre-exercise and post-exercise conditions. Gain scores for whole sample HV, female HV, and TROM-E were statistically different although differences were small and not meaningful. Significant AUC and acceptable pre-exercise cutoff values included 375 ml. for female HV (sensitivity 89%, specificity 87%), 505 ml. for male HV (sensitivity 81%, specificity 70%), 82 degrees for TROM-E (sensitivity 92%, specificity 71%), and 73 degrees of TROM-F (sensitivity 90%, specificity 89%).

CONCLUSIONS

Potential at-risk OI-related populations, especially unaffected limbs of UULA persons, are best identified by pre-exercise cutoff values using HV by gender, TROM, and single-site SWM 2.83.

A Prospective Evaluation of Duplex Ultrasound for Thoracic Outlet Syndrome in High-Performance Musicians Playing Bowed String Instruments

Thoracic outlet syndrome (TOS) is a neurovascular condition involving the upper extremity, which is known to occur in individuals who perform chronic repetitive upper extremity activities. We prospectively evaluate the incidence of TOS in high-performance musicians who played bowed string musicians. Sixty-four high-performance string instrument musicians from orchestras and professional musical bands were included in the study. Fifty-two healthy volunteers formed an age-matched control group. Bilateral upper extremity duplex scanning for subclavian vessel compression was performed in all subjects. Provocative maneuvers including Elevated Arm Stress Test (EAST) and Upper Limb Tension Test (ULTT) were performed. Abnormal ultrasound finding is defined by greater than 50% subclavian vessel compression with arm abduction, diminished venous waveforms, or arterial photoplethysmography (PPG) tracing with arm abduction. Bowed string instruments performed by musicians in our study included violin (41%), viola (33%), and cello (27%). Positive EAST or ULTT test in the musician group and control group were 44%, and 3%, respectively (p = 0.03). Abnormal ultrasound scan with vascular compression was detected in 69% of musicians, in contrast to 15% of control subjects (p = 0.03). TOS is a common phenomenon among high-performance bowed string instrumentalists. Musicians who perform bowed string instruments should be aware of this condition and its associated musculoskeletal symptoms.

Musicians react faster and are better multisensory integrators

The results from numerous investigations suggest that musical training might enhance how senses interact. Despite repeated confirmation of anatomical and structural changes in visual, tactile, and auditory regions, significant changes have only been reported in the audiovisual domain and for the detection of audio-tactile incongruencies. In the present study, we aim at testing whether long-term musical training might also enhance other multisensory processes at a behavioural level. An audio-tactile reaction time task was administrated to a group of musicians and non-musicians. We found significantly faster reaction times with musicians for auditory, tactile, and audio-tactile stimulations. Statistical analyses between the combined uni- and multisensory reaction times revealed that musicians possess a statistical advantage when responding to multisensory stimuli compared to non-musicians. These results suggest for the first time that long-term musical training reduces simple non-musical auditory, tactile, and multisensory reaction times. Taken together with the previous results from other sensory modalities, these results strongly point towards musicians being better at integrating the inputs from various senses.

Hand Sensibility, Strength, and Laxity of High-Level Musicians Compared to Nonmusicians

PURPOSE

To determine whether musicians have more sensitive, stronger, and flexible hands than nonmusicians.

METHODS

A total of 100 musicians and 100 control subjects were assessed for 2-point discrimination, Semmes-Weinstein monofilament light touch, grip and pinch strength, and laxity. Musicians were included if enrolled as instrumental performance majors at a 4-year accredited conservatory of music. Nonmusician controls were university students who never or rarely engaged in playing an instrument. All subjects were between the ages of 18 and 28. The exclusion criterion was history of any hand condition, trauma, surgery, or diabetes. Statistical analyses were carried out using the t test, analysis of variance, and correlation coefficients as appropriate.

RESULTS

High-level musicians in our cohort showed the same handedness (dominance) as the general population. The musicians were weaker than the nonmusicians. Male musicians were significantly weaker in pinch and grip bilaterally than nonmusicians, whereas female musicians were significantly weaker only in grip on the right/dominant side. Two-point discrimination was significantly less in musicians for the left/nondominant index, ring, and small fingers, and the right/dominant small and dominant index finger. Semmes-Weinstein testing was significantly better for the right/dominant digits, including the thumb, but not the left digits with the exception of the ring and nondominant middle and ring. There was no difference in laxity between the 2 groups.

CONCLUSIONS

High-level musicians have, in general, more sensitive but weaker hands than nonmusicians, but the differences seem small and may not be clinically important.