Reduction in finger blood flow induced by hand-transmitted vibration: effect of hand elevation

Exposure to hand-arm vibrations in the workplace and the occurrence of hand-arm vibration syndrome, Dupuytren's contracture, and hypothenar hammer syndrome: a systematic review and meta-analysis

This study provides an overview of the relationships between exposure to work-related hand-arm vibration and the occurrence of pre-defined disorders of the hands. We searched Medline, Embase, Web of Science, Cochrane Central, and PsycINFO for cross-sectional and longitudinal studies on the association between work-related vibration exposure and the occurrence of hand-arm vibration syndrome (including vibration-induced white finger), Dupuytren's contracture, or hypothenar hammer syndrome. We used a 16-item checklist for assessing the risk of bias. We present results narratively, and we conducted random effects meta-analyses if possible. We included 10 studies with more than 24,381 participants. Our results showed statistically significant associations between the exposure to hand-arm vibrations and the occurrence of the selected disorders, with pooled odds ratios ranging between 1.35 (95% CI: 1.28 to 2.80) and 3.43 (95% CI: 2.10 to 5.59). Considerable between-study heterogeneity was observed. Our analyses show that exposure to vibrating tools at work is associated with an increased risk for the occurrence of selected disorders of the hands. Due to the majority of studies being cross-sectional, no firm conclusion is possible regarding causal relationships between vibration exposure and disorder occurrence. Future research should specifically address whether reducing exposure to hand-held vibrating tools at work reduces the incidence of the disorders of the hands investigated in this systematic review.

A reliability study of a novel visual ischemic palpation scale in an experimental setting

BACKGROUND

Manual palpation is an important part of the clinical examination and generally it has low reliability. The aim of this study was to assess the reliability of a novel method for discriminating 3 different levels of palpation force.

METHODS

This reliability study included 96 healthy physiotherapists and physiotherapy students, who have been taught a new palpation graduated procedure called Visual Ischemic Palpatory Scale (VIPS), aimed to classify the applied pressure based on the finger's ischemia. Force was recorded by a force measurement system putting sensor over a rigid surface. To study the characteristic of VIPS the analysis of variance (ANOVA), Spearman rank correlation coefficient, Intraclass Correlation Coefficient (ICC), Standard Error of Measurements (SEM), and Minimal Detectable Change (MDC) were calculated.

RESULTS

Three distinct degrees were found with distinct forces expression: 1st degree 76.04 g (95% CI 65.86-86.22), 2nd degree 307.87 g (95% CI 263.29-352.44) and 3rd degree 1319.48 g (CI 1204.73-1434.23). Male participants significantly recorded a greater force than females. Good to excellent reliability across degrees were found (0.89 [95% CI: 0.82-0.97]), and final agreement found that more than 65.6% of sample recorded a force in the cut-offs identified. SEM values became bigger as the recorded force increased and MDC were equal to 48.94 g, 188.73 g, and 379.24 g for 1st, 2nd, and 3rd degree, respectively.

CONCLUSIONS

VIPS would appear to have three distinct degrees, sex dependent, with specific force expression for each degree and a good to excellent intra-rater reliability, but a poor agreement between raters.

Tremor measurements in a 22-year cohort study of workers exposed to hand-held vibrating tools

OBJECTIVES

The objectives of this cohort study were to evaluate possible long-term effects of occupational exposure to hand-arm vibration (HAV) in terms of increased tremor. The aims were to evaluate whether exposure during follow-up, baseline hand-arm vibration syndrome (HAVS), baseline manual dexterity or current medical conditions or life-style habits might be associated with increased tremor. A further aim was to compare two different activation conditions: postural vs rest tremor.

METHODS

Forty men (current age: 60.4 years) who had previously worked as manual workers in a specialized engineering and construction company enrolled in the study. Their hand functions had been examined in 1994. At the baseline examination, 27 had been diagnosed with HAVS, while 13 were not exposed. The follow-up examination in 2016-2017 comprised the CATSYS Tremor Pen^® for measuring postural and rest tremor and the Grooved Pegboard Test for assessing manual dexterity. Blood samples were taken for assessing biomarkers that might have impact on tremor.

RESULTS

Neither cumulative exposure to HAV during follow-up nor HAVS at baseline were associated with increased tremor. A test for manual dexterity at baseline was significantly associated with increased tremor (Tremor Intensity) at follow-up. Blood markers of current medical conditions and tobacco consumption were associated with increased tremor. Rest tremor frequency was higher than postural tremor frequency (p < 0.001).

CONCLUSIONS

The main findings of this 22-year cohort study were no indications of long-term effects on tremor related to HAV exposure and previous HAVS status. However, baseline manual dexterity was significantly associated with increased tremor at follow-up. Activation conditions (e.g., hand position) are important when testing tremor.

Local Vibrational Therapy for Essential Tremor Reduction: A Clinical Study

Background and objectives: tremor is an unintentional and rhythmic movement of any part of the body that is a typical symptom of Essential Tremor (ET). ET impairs the quality of life of patients and is treated with pharmacotherapy. We investigated the tremor reduction efficacy of an innovative vibrational medical device (IMD) in ET patients. Materials and Methods: we conducted a prospective, single-center, single-arm, pragmatic study in ET patients with an extended safety study to evaluate the efficacy and safety of the Vilim Ball-a local hand-arm vibration device that produces vibrations in the frequency range of 8-18 Hz and amplitude from 0 to 2 mm. The primary endpoint was the decrease in the power spectrum after device use. The secondary endpoints were safety outcomes. Results: In total, 17 patients with ET were included in the main study, and no patients withdrew from the main study. The tremor power spectrum (m²/s³ Hz) was lower after the device use, represented as the mean (standard deviation): 0.106 (0.221); median (Md) 0.009 with the interquartile range; IQR, 0.087 vs. 0.042 (0.078); Md = 0.009 with the IQR 0.012; Wilcoxon signed-rank test V = 123; and p = 0.027. Seven patients reported that vibrational therapy was not effective. Two patients reported an increase in tremor after using the device. In the extended safety study, we included 51 patients: 31 patients with ET and 20 with Parkinsonian tremor, where 48 patients reported an improvement in tremor symptoms and 49 in function. No serious adverse events were reported, while two patients in the Parkinsonian tremor group reported a lack of efficacy of the proposed medical device. Conclusions: the device reduces essential tremor in some patients and is safe to use in ET.

Tremor and hand-arm vibration syndrome (HAVS) in road maintenance workers

Objectives

The aim of this study was to evaluate postural and rest tremor among workers using vibrating hand tools, taking into account the possible effects of toxicants such as alcohol and tobacco. A further aim was to study workers diagnosed with hand-arm vibration syndrome (HAVS) at the time of examination.

Methods

This study comprises 103 road maintenance workers, 55 exposed to vibrating hand tools (age 41.0 years; range 21–62) and 48 referents (age 38.5 years; range 19–64). They were examined with the CATSYS Tremor Pen^®. Exposure to vibrating tools and serum biomarkers of alcohol and tobacco consumption were measured.

Results

Cumulative exposure to vibrating tools was associated with increased postural (p < 0.01) and rest tremor (p < 0.05) and with a higher Center Frequency of postural tremor (p < 0.01) among smokers and users of smokeless tobacco. Rest tremor Center Frequency was higher than postural tremor frequency (p < 0.001).

Conclusions

The main findings indicate an association between cumulative exposure to hand-held vibrating tools, tremor parameters and consumption of tobacco products. The hand position is important when testing for tremor. Rest tremor had a higher Center Frequency. Postural tremor was more strongly associated with exposure than rest tremor. The finding of increased tremor among the HAVS subjects indicated that tremor might be a part of the clinical picture of a HAVS diagnosis. As with all cross-sectional studies, inferences should be made with caution when drawing conclusions about associations between exposure and possible effects. Future research using longitudinal design is required to validate the findings of the present study.

Reductions in finger blood flow induced by 125-Hz vibration: effect of location of contact with vibration

PURPOSE

This study investigated whether the reductions in finger blood flow induced by 125-Hz vibration applied to different locations on the hand depend on thresholds for perceiving vibration at these locations.

METHODS

Subjects attended three sessions during which vibration was applied to the right index finger, the right thenar eminence, or the left thenar eminence. Absolute thresholds for perceiving vibration at these locations were determined. Finger blood flow in the middle finger of both hands was then measured at 30-s intervals during five successive 5-min periods: (i) pre-exposure, (ii) pre-exposure with 2-N force, (iii) 2-N force with vibration, (iv) post-exposure with 2-N force, (v) recovery. During period (iii), vibration was applied at 15 dB above the absolute threshold for perceiving vibration at the right thenar eminence.

RESULTS

Vibration at all three locations reduced finger blood flow on the exposed and unexposed hand, with greater reductions when vibrating the finger. Vibration-induced vasoconstriction was greatest for individuals with low thresholds and locations of excitation with low thresholds.

CONCLUSIONS

Differences in vasoconstriction between subjects and between locations are consistent with the Pacinian channel mediating both absolute thresholds and vibration-induced vasoconstriction.