Hand function in workers with hand-arm vibration syndrome

Effects of chronic neck pain on grip strength and psychomotor skills in adults

BACKGROUND

It can be challenging to perform activities of daily living in patients with chronic neck pain. As the severity of the pain increases, the quality of the movements decreases. Not only the neck, but also the shoulder, elbow, grip strength and psychomotor skills are affected by these pains.

OBJECTIVE

In this study, it was aimed to investigate the effect of neck pain on grip strength and psychomotor skills in adults diagnosed with chronic neck pain.

METHODS

A cross-sectional study was conducted to examine the effect of pain on grip strength and psychomotor skills in patients with chronic neck pain. This study was planned to be carried out between October 2019 and May 2020 at the Private Yaşam Medical Center in Adana, with the official permission of the institution manager, but this period was carried out between October 2019 and November 2020 due to the fact that sufficient number of patients could not be reached due to the COVID-19 global epidemic. A total of 80 individuals, including 40 control and 40 patients, were included in the study. Forty adult patients who applied to the clinic with a diagnosis of chronic neck pain and 40 healthy adults without a diagnosis of chronic neck pain were included in the study. Conducted with 80 adults between the age of 19 and 74 years old. Individuals were divided into Group 1-control group (n = 40) and Group 2-patient group (n = 40). Information such as age, height, body weight and occupation of the groups were noted. Visual analogue scale and Neck Disability Index were applied to both the groups; hand grip strength with a Jamar hydraulic hand dynamometer, finger lateral grip strength with a pinchmeter and psychomotor skills with the Purdue Pegboard test were evaluated.

RESULTS

In the study, hand grip strength (p < .05), finger lateral grip strength (p < .05), psychomotor skills (p < .01) showed a statistically significant decrease in the patient group compared to the control group.

CONCLUSION

It is thought that in addition to the routine treatments for neck pain in the treatment plan of patients with chronic neck pain, exercises to improve the functionality and psychomotor skills in daily living activities can be included in the direction of increasing the grip strength and will guide future studies.

Postoperative cognitive disorders and delirium in gynecologic surgery: Which surgery and anesthetic techniques to use to reduce the risk?

Despite their general good health, an increasing proportion of elderly individuals require surgery due to an increase in average lifespan. However, because of their increased vulnerability, these patients need to be handled carefully to make sure that surgery does not cause more harm than good. Age-related postoperative cognitive disorders (POCD) and postoperative delirium (POD), two serious consequences that are marked by adverse neuropsychologic alterations after surgery, are particularly dangerous for the elderly. In the context of gynecologic procedures, POCD and POD are examined in this narrative review. The main question is how to limit the rates of POCD and POD in older women undergoing gynecologic procedures by maximizing the risk-benefit balance. Three crucial endpoints are considered: (1) surgical procedures to lower the rates of POCD and POD, (2) anesthetic techniques to lessen the occurrence and (3) the identification of individuals at high risk for post-surgery cognitive impairments. Risks associated with laparoscopic gynecologic procedures include the Trendelenburg posture and CO2 exposure during pneumoperitoneum, despite statistical similarities in POD and POCD frequency between laparoscopic and laparotomy techniques. Numerous risk factors are associated with surgical interventions, such as blood loss, length of operation, and position holding, all of which reduce the chance of complications when they are minimized. In order to emphasize the essential role that anesthesia and surgery play in patient care, anesthesiologists are vital in making sure that anesthesia is given as sparingly and quickly as feasible. In addition, people who are genetically predisposed to POCD may be more susceptible to the disorder. The significance of a thorough strategy combining surgical and anesthetic concerns is highlighted in this article, in order to maximize results for senior patients having gynecologic surgery.

A follow-up study of vibration-induced injuries in workers exposed to transient and high frequency vibrations

BACKGROUND

In a previous study from 2018, 38 wheel loader assembly workers were examined, showing high exposures to transient and high-frequency vibrations. After the investigation, preventive measures were immediately implemented to reduce the vibration exposure. In 2022, a follow-up study was carried out to examine the effect of these measures.

METHODS

The follow-up study included 35 (27 men and 8 women) of the original 38 workers. They were divided into two groups, 24 workers with ongoing vibration exposure and 11 workers, not vibration exposed since 2018. All participants completed a questionnaire and underwent a thorough examination, including several neurophysiological tests and a comprehensive assessment of musculoskeletal symptoms. The questionnaire responses and on-site vibration level measurements formed the basis for the individual vibration exposure assessment.

RESULTS

In 2018, clear differences were noted between the two groups regarding vibration perception thresholds (VPT), needle test, 2-PD (2-point discrimination), and monofilament test with deviating results in the unexposed group. The difference between the two groups was significantly smaller at the follow-up examination in 2022, where differences remained for VPT and monofilament tests, with deviating test results in the unexposed group. When comparing variable values between 2018 and 2022 within the exposed and unexposed groups, respectively, the unexposed group showed mostly unchanged values, while a deterioration was observed for VPT, needle test and temperature sensitivity test among the exposed workers during follow-up. The prevalence of VWF (Vibration white fingers) was around 30-40% and neuropathy around 75% among exposed workers during follow-up compared to about 60% and 85% respectively, in the unexposed group.

CONCLUSION

The overall categorization of white fingers and neuropathy, according to the Stockholm Workshop Scale, remained largely unchanged in both study groups from 2018 to 2022. The introduction of cost-effective and relatively simple preventive measures may have contributed to this result. Throughout the follow-up period, the number of exposed workers who developed musculoskeletal disorders and newly reported cases of vibration injuries at the factory decreased. Without this preventive program, increased vascular and nerve symptoms would most likely have occurred during follow-up due to continued vibration exposure.

Applied Force Alters Sensorineural and Peripheral Vascular Function in a Rat Model of Hand-Arm Vibration Syndrome

OBJECTIVE

This study described the effects of applied force (grip) on vascular and sensorineural function in an animal model of hand-arm vibration syndrome (HAVS).

METHODS

Rat tails were exposed to 0, 2, or 4 N of applied force 4 hr/d for 10 days. Blood flow and sensitivity to transcutaneous electrical stimulation and pressure were measured.

RESULTS

Applied force increased blood flow but reduced measures of arterial plasticity. Animals exposed to force tended to be more sensitive to 250-Hz electrical stimulation and pressure applied to the tail.

CONCLUSIONS

Effects of applied force on blood flow and sensation are different than those of vibration. Studies examining co-exposures to force and vibration will provide data that can be used to determine how these factors affect risk of workers developing vascular and sensorineural dysfunction (ie, HAVS).

A Review of Hand-Arm Vibration Studies Conducted by US NIOSH since 2000

Studies on hand-transmitted vibration exposure, biodynamic responses, and biological effects were conducted by researchers at the Health Effects Laboratory Division (HELD) of the National Institute for Occupational Safety and Health (NIOSH) during the last 20 years. These studies are systematically reviewed in this report, along with the identification of areas where additional research is needed. The majority of the studies cover the following aspects: (i) the methods and techniques for measuring hand-transmitted vibration exposure; (ii) vibration biodynamics of the hand-arm system and the quantification of vibration exposure; (iii) biological effects of hand-transmitted vibration exposure; (iv) measurements of vibration-induced health effects; (iv) quantification of influencing biomechanical effects; and (v) intervention methods and technologies for controlling hand-transmitted vibration exposure. The major findings of the studies are summarized and discussed.

Validity and reliability of the Turkish version of the Cold Intolerance Symptom Severity Questionnaire

Background/aim

The aim of this study was to determine validity and reliability of the Turkish version of the Cold Intolerance Symptom Severity (CISS-T) Questionnaire.

Materials and methods

The translation and back translation steps of the study were based on the Beaton guidelines. Sixty-eight patients between 18 and 65 years old with cold intolerance after amputation, replantation, multiple crush syndrome, and peripheral nerve injury were included in the study. Patients completed the Disabilities of the Arm, Shoulder, and Hand Questionnaire (DASH), the SF-36 Quality of Life Questionnaire, and the single questions assessing the cold sensitivity and cold intolerance once and the final version of the CISS-T twice with a 7-day interval.

Results

The internal consistency (Cronbach α = 0.844) and test-retest reliability (r = 0.938) of CISS-T were assessed and both were considerably high. Also, the correlations between the scores of the CISS-T, DASH-T, SF-36-T, and the single questions were analyzed by Spearman’s correlation coefficient. The CISS-T showed an excellent correlation with the single questions (rho = 0.8 and 0.877), a good and negative correlation with the pain subscale of the SF-36 (rho = 0.617), and a moderate correlation with the DASH-T (rho = 0.592).

Conclusion

As a result, the CISS-T is a valid and reliable instrument to assess the severity of cold intolerance.

Hand-arm vibration syndrome: Workers' experience with functional impairment and disability

STUDY DESIGN

Qualitative and descriptive study.

INTRODUCTION

Hand-arm vibration syndrome (HAVS) is a prevalent disease in Canada. There is little work on the perspectives of HAVS patients.

PURPOSE OF THE STUDY

Explore perceptions of disability and functional compromise in patients with HAVS.

METHODS

Semi-structured telephone interviews were conducted with HAVS patients and analysed using content analysis.

RESULTS

The 11 participants reported numbness, pain, and reduced dexterity, strength, and sensation. Participants noted that HAVS was an inevitable aspect of their work. They indicated frustration with their condition and viewed it as a disability. To overcome impairments risky strategies are often used. Participants reported lack of support to manage symptoms and overcome work disability.

DISCUSSION

HAVS related impairment is disabling. Workers require improved resources and support to address symptom management and safe strategies to minimize work disability.

CONCLUSION

HAVS patients experience functional, social, emotional, and psychological disability.

LEVEL OF EVIDENCE

Not applicable.

A systematic review of diagnostic performance of quantitative tests to assess musculoskeletal disorders in hand-arm vibration syndrome

The purpose was to systematically review the published reports for the clinical utility of quantitative objective tests commonly used for diagnosing musculoskeletal disorders in hand-arm vibration syndrome (HAVS). Two reviewers independently conducted a computerized literature search in PubMed and Scopus using predefined criteria, and relevant papers were identified. The articles were screened in several stages and considered for final inclusion. Quality of the selected papers was evaluated by a modified QUADAS tool. Relevant data were extracted as necessary. For this review, only 4 relevant studies could be identified for detailed examination. Grip strength, pinch strength, and Purdue pegboard tests were commonly used with their reported sensitivity and specificity ranging between 1.7 to 65.7% and 65.2 to 100%, 1.7 to 40% and 94 to 100%, and 44.8 to 85% and 78 to 95%, respectively. A considerable difference across the studies was observed with respect to patient and control populations, diagnostic performance and cut-off values of different tests. Overall, currently available English-language limited literature do not provide enough evidence in favour of the application of grip strength and pinch strength tests for diagnosing musculoskeletal injuries in HAVS; Purdue pegboard test seems to have some diagnostic value in evaluating impaired dexterity in HAVS.

Quantitative neurosensory findings, symptoms and signs in young vibration exposed workers

Background

Long-term exposure to hand-held vibrating tools may cause the hand arm vibration syndrome (HAVS) including vibration induced white fingers and sensorineural symptoms. The aim was to study early neurosensory effects by quantitative vibrotactile and monofilament tests in young workers with hand-held vibration exposure.

Methods

This cross-sectional study consisted of 142 young, male machine shop and construction workers with hand-held exposure to vibrating tools. They were compared with 41 non-vibration exposed subjects of the same age-group. All participants passed a structured interview, answered several questionnaires and had a physical examination including the determination of vibrotactile perception thresholds (VPTs) at two frequencies (31.5 and 125 Hz) and Semmes Weinstein’s Monofilament test.

Results

In the vibration exposed group 8% of the workers reported episodes of tingling sensations and 10% numbness in their fingers. Approximately 5–10% of the exposed population displayed abnormal results on monofilament tests. The vibrotactile testing showed significantly increased VPTs for 125 Hz in dig II bilaterally (right hand, p = 0.01; left hand, p = 0.024) in the vibration exposed group.

A multiple regression analysis (VPT - dependent variable; age, height, examiner and five different vibration dose calculations – predictor variables) in dig II bilaterally showed rather low R²-values. None of the explanatory variables including five separately calculated vibration doses were included in the models, neither for the total vibration exposed group, nor for the highest exposed quartile.

A logistic multiple regression analysis (result of monofilament testing - dependent variable; age, height, examiner and five vibration dose calculations – predictor variables) of the results of monofilament testing in dig II bilaterally gave a similar outcome. None of the independent variables including five calculated vibration doses were included in the models neither for the total exposed group nor for the highest exposed quartile.

Conclusion

In spite of the fairly short vibration exposure, a tendency to raised VPTs as well as pathologic monofilament test results was observed. Thus, early neurophysiologic symptoms and signs of vibration exposure may appear after short-term exposure also in young workers.

Development of the International Classification of Functioning, Disability and Health core sets for hand conditions--results of the World Health Organization International Consensus process

PURPOSE

A formal decision-making and consensus process was applied to develop the first version of the International Classification on Functioning, Disability and Health (ICF) Core Sets for Hand Conditions.

METHOD

To convene an international panel to develop the ICF Core Sets for Hand Conditions (HC), preparatory studies were conducted, which included an expert survey, a systematic literature review, a qualitative study and an empirical data collection process involving persons with hand conditions. A consensus conference was convened in Switzerland in May 2009 that was attended by 23 healthcare professionals, who treat hand conditions, representing 22 countries.

RESULTS

The preparatory studies identified a set of 743 ICF categories at the second, third or fourth hierarchical level. Altogether, 117 chapter-, second-, or third-level categories were included in the comprehensive ICF Core Set for HC. The brief ICF Core Set for HC included a total of 23 chapter- and second-level categories.

CONCLUSIONS

A formal consensus process integrating evidence and expert opinion based on the ICF led to the formal adoption of the ICF Core Sets for Hand Conditions. The next phase of this ICF project is to conduct a formal validation process to establish its applicability in clinical settings.

Cut-off value for self-reported abnormal cold sensitivity and predictors for abnormality and severity in hand injuries

Our aim was to identify a cut-off value for self-reported, abnormal cold sensitivity and to identify cold sensitivity predictors after hand injuries. The Cold Intolerance Symptom Severity (CISS) questionnaire and a VAS question concerning discomfort on exposure to cold were investigated in 94 normal people and 88 patients. A CISS score >50 was defined as abnormal cold sensitivity. Multiple injured digits, an increased number of injured vessels, complete nerve injury and replantation were variables associated with high VAS scores. Factors linked to both abnormality and worse CISS or VAS scores were: the presence of bone injury; a larger number of repaired vessels; the use of vascular grafts and a high Hand Injury Severity Score (HISS). The causes of abnormality and severity suggest a multifactorial aetiology with bony, vascular and neural components. A cut-off for abnormality is useful for descriptive, comparative and assessment purposes.

Self-reported cold sensitivity in normal subjects and in patients with traumatic hand injuries or hand-arm vibration syndrome

BACKGROUND

Cold sensitivity is a common and disabling complaint following hand injuries. The main purpose of this study was to describe self-reported consequences of cold sensitivity and the association with disability and health-related quality of life in patients with hand injuries or hand-arm vibration syndrome (HAVS) and in normal subjects.

METHODS

Responses to the Cold Intolerance Symptom Severity (CISS) questionnaire, Potential Work Exposure Scale (PWES), Disability of the Arm, Shoulder and Hand (DASH) and Short-Form 36 questionnaire (SF-36) were investigated in normal subjects (n = 94), hand injured patients (amputation and nerve injuries, n = 88) and patients with HAVS (n = 30). The results are presented as median (range), percent and mean deviation from norms. The Kruskal Wallis Test or Mann-Whitney U-Test were used to identify significant differences between multiple groups or subgroups. The Spearman rank correlation was used to study the relationship between cold sensitivity and disability.

RESULTS

Abnormal cold sensitivity (CISS score > 50) was seen in 75% and 45% of patients with HAVS and a traumatic hand injury, respectively. Patients were significantly more exposed to cold in their work environment than the normal population, with a consequently negative effect on work ability due to cold sensitivity. Patients with abnormal cold sensitivity were more seriously disabled and had a poorer health-related quality of life than patients with normal cold sensitivity [higher DASH scores and e.g. significantly larger mean deviation from norms in the subscales Role Physical and Bodily Pain (SF-36)].

CONCLUSION

Severe and abnormal cold sensitivity may have a profound impact on work capacity, leisure, disability and health-related quality of life. It is frequently seen in patients with traumatic hand injuries and particularly apparent in patients with HAVS.

Occupational changes in manual tactile sensibility of the dentist

The aim of this study was to find out if the use of vibrating tools (drill, ultrasonic scaler ...) in dental practice has negative side effects on the manual tactile sensibility of the dentist. The sensory tests were performed on 50 subjects, who were allocated to three different groups according to their occupation and the length of their working experience. The first test group consisted of 20 dentists, who had more than 25 years of work experience. As a control group, 20 non-dentists were recruited to obtain a similar age distribution as the former test group. A final group consisted of 10 dentists with more than 1 year of work experience. All subjects underwent three tests: light-touch sensation test, two-point discrimination test and thermal sensation test on the thumb and the index finger of the working and non-working hands. Results showed significant differences, especially for the light-touch sensation test. The study showed more specifically that the tactile sensibility of the working hand of the dentists with more than 25 years of work experience was significantly diminished with respect to the non-working hand and to the working hand of non-dentists. In the test group of young dentists, there was no noticeable reduction of manual tactile sensibility.

Is there a relationship between light touch-pressure sensation and functional hand ability?

PURPOSE

To investigate and compare the level of light touch-pressure sensation as tested via the Semmes Weinstein monofilament (SWM) test with the level of functional hand ability.

METHODS

Twenty-seven persons with isolated sensory deficit due to leprosy and 31 healthy controls were tested in the Occupational Therapy department of a hospital for patients with Hansen's disease. Palmar light touch thresholds were determined by SMW testing. Functional hand ability was tested via the Jebsen-Taylor Hand Function Test (JTHFT) and the Functional Dexterity Test (FDT). All participants were measured by manual muscle testing (MMT) to exclude any motor impairment. Data analysis compared sensory thresholds and level of functional hand ability between the two groups and examined the relationship between the variables.

RESULTS

In the group with sensory deficit, the sensory thresholds were significantly higher than in the control group. Significant correlations were found between the sensory thresholds measured by the SWM test and the FDT and JTHFT scores, with higher correlations found for tasks entailing manipulation of small objects.

CONCLUSIONS

The findings support the existence of a relationship between sensory light touch thresholds tested by the Semmes Weinstein monofilaments (SWMs) and hand function. However, the SWM test alone is not sufficient as an indicator of hand function and must therefore be supplemented with other hand function tests.

Upper extremity disability in workers with hand-arm vibration syndrome

BACKGROUND

Hand-arm vibration syndrome (HAVS) is a common occupational problem and it is important to understand the disability associated with this condition.

AIMS

To measure upper extremity disability using the disabilities of the arm, shoulder and hand (DASH) questionnaire in workers with HAVS and to determine how this disability is affected by the vascular and neurological components of HAVS and other factors, in particular musculoskeletal variables.

METHODS

Subjects were recruited from HAVS patients assessed at St Michael's Hospital, Toronto, Canada, over a 2-year period. All participants were assessed by an occupational medicine specialist to determine the specific components of HAVS and musculoskeletal variables including upper extremity pain score measured by the Borg scale. The DASH questionnaire was completed on the same day as the clinical assessment and before any feedback had been given about the clinical findings.

RESULTS

A total of 141 workers with HAVS were recruited and 139 agreed to participate in the study. This study group had a statistically significantly higher mean DASH score than the US population (P < 0.001). The multiple linear regression analysis indicated that upper extremity pain score (P < 0.001), the Stockholm sensorineural scale (P < 0.01) and the number of fingers blanching (P < 0.05) had a statistically significant association with an increase in the DASH score. The highest partial R(2) value was for the upper extremity pain score.

CONCLUSIONS

Workers with HAVS have significant upper extremity disability and musculoskeletal factors appear to make an important contribution to this disability.

Hand-arm vibration syndrome with use of anti-vibration chain saws: 19-year follow-up study of forestry workers

OBJECTIVES

Hand-arm vibration syndrome (HAVS) consists of vascular and neurological component. Musculoskeletal component has not been delineated yet. In the present follow-up study, we evaluated the prevalence of HAVS and the cumulative exposure to vibration among a cohort of forestry workers. Special interest was given to numbness and musculoskeletal disorders of upper extremity and neck in forestry workers.

METHODS

A follow-up study starting from 1976 was conducted among forestry workers in Suomussalmi in Finland. Total exposure of hand-arm vibration was recorded during 11 cross-sectional surveys. The last study was carried out in 1995. The lifetime dose of vibration energy was calculated. A cohort of 52 forest workers participated to all 11 cross-sectional surveys 1976-1995. HAVS and musculoskeletal disorders were evaluated.

RESULTS

The prevalence of active vibration white finger (VWF) decreased from 13 to 4% in the cross-sectional study. In the cohort VWF decreased from 17 to 8% and numbness increased from 23 to 40%. Rotator cuff syndrome (P=0.034) and epicondylitis (P=0.004) associated with numbness. Regional neck pain was diagnosed in 38% of workers and associated with low back pain. In modeling VWF, the lifelong vibration energy (OR 1.03, CI 1.01-1.05), and smoking (OR 7.36, CI 1.07-50.76) were significant. Numbness was modeled by pain in upper extremities (OR 12.43, CI 2.42-63.80) and neck pain (5.97, CI 1.25-28.39), not by lifelong vibration energy. Right rotator cuff syndrome was modeled by age (OR 2.58, CI 1.04-6.41) and lifelong vibration energy (OR 1.04, CI 1.00-1.07).

CONCLUSIONS

The prevalence of VWF constantly decreased. Numbness did not follow the vibration exposure profile. Numbness also associated with upper extremity musculoskeletal disorders. Hand-arm vibration associated with the right rotator cuff syndrome in forestry workers.

Potential occupational health problems for dentists in Flanders, Belgium

The aim of this study was to gather data on occupational health effects among Flemish dentists. A questionnaire on various potential health effects was sent out to randomly selected Flemish dentists. Pilot experimental studies were performed on hearing and sensory function of the fingers on small groups of dentists. Audiometric data of both ears, gathered with an interval of 10 years, were analysed. Sensory tests of the fingers were performed for dominant and non-dominant hands in relation to exposure time to (ultra)sonic equipment. Positive responses for the questionnaire were as follows: low back pain, 54% (stress-correlated); vision problems, 52.3% (age-correlated); infections, 9%; allergies, 22.5% (mainly latex); stress level was scored 7 on a scale from 0 to 10; diminished sensitivity of the fingertips, 6% and auditory disorders, 19.6%. Pilot audiometric data showed a hearing loss at 4,000 Hz for the left ear, presumably indicative of occupational noise trauma. The two-point discrimination ability of the dominant hand tended to diminish in line with the number of years of practice. Dentists in Flanders were found to suffer from various health-related problems. More elaborate studies are required to provide more details on the risks for occupational hearing impairment and vibration hand neuropathy and to determine whether the problems described were related to the practice of dentistry.

Impaired manual dexterity and neuromuscular dysfunction in patients with hand-arm vibration syndrome

Manual dexterity and hand functional difficulties in daily life in hand-arm vibration syndrome (HAVS) were investigated in 29 male patients with HAVS and 30 male controls without occupational exposure to hand-arm vibration. Manual dexterity was assessed by measuring the performance time of picking up and transferring 30 red beans, one by one, from one plate to another. Vibrotactile perception thresholds at 125 Hz and grip strength were also examined. Hand functional difficulties in daily life were surveyed with a questionnaire. The HAVS patients had an increased vibrotactile threshold, decreased grip strength, and low performance in transferring beans. Low performances with transfer times over 53 s (2SD from the mean in the controls) were found in 66% of the HAVS patients and 3% of the controls. Bean transfer times in the patients were correlated with an increasing vibrotactile threshold and decreasing grip strength. The transfer times of the patients were also associated with hand functional difficulties such as picking up coins, turning the pages of a newspaper, buttoning clothes, and pouring from a teapot. The patients with a prolonged transfer time over 60 s (3SD from the mean in the controls) were most likely to have hand functional difficulties. The present findings suggest that measurement of the bean transfer time will serve to assess manual dexterity among HAVS patients, and that impaired manual dexterity in patients may be associated with impaired sensory feedback and muscular dysfunction in the fingers and hands.

Hand muscle pathology after long-term vibration exposure

The morphology of the abductor pollicis brevis muscle was studied in 20 patients suffering from hand-arm vibration syndrome. The main morphological changes observed were centrally located myonuclei and fibre type grouping (found in all 20 muscle biopsies), angulated muscle fibres (found in 19 biopsies), ring fibres and regenerating fibres (found in 18 biopsies) and fibrosis (found in 17 biopsies). The observed abnormalities are believed to reflect damage to both the muscle fibres and the motor nerve. The changes were related to different vibration exposure parameters. The number of fibres demonstrating centrally located nuclei correlated significantly with the cumulative vibration exposure, while the number of angulated fibres correlated significantly with the total vibration exposure time. This indicates that the vibrating tools may cause direct damage to muscle fibres as well as nerves.

Hand function tests and questions on hand symptoms as related to the Stockholm workshop scales for diagnosis of hand-arm vibration syndrome

The severity of hand-arm vibration syndrome (HAVS) is usually graded according to the Stockholm workshop scales. Although the Stockholm workshop scales are regarded the gold standard for assessing the severity of HAVS, they are based primarily on subjective symptoms. The aim of the present study was to explore the agreement between Stockholm workshop scales and the outcome from ten well-defined clinical tests commonly used in hand rehabilitation for assessment of hand function. One hundred and eleven vibration-exposed workers participated in the study. Ten objective tests of hand function and four questions on subjective hand symptoms were included. The results indicated that, out of these tests, perception of vibration, perception of touch/pressure and dexterity showed a moderate agreement with Stockholm workshop scales. Among specific questions on hand symptoms, cold intolerance and pain showed a high agreement with Stockholm workshop scales. It is concluded that defined objective tests combined with directed questions on specific hand symptoms, together with the Stockholm workshop scales, may be helpful for diagnosing HAVS.

Hand-arm-vibration syndrome (HAVS): is there a central nervous component? An fMRI study

Hand-held vibrating tools may result in neuromuscular dysfunction and vasospastic problems of the hand. Sensory and motor dysfunction can be explained by injury to peripheral structures, but could also be due to changes in cortical somatotopic mapping of the hand in the brain. The purpose of the present study was to use functional magnetic resonance imaging (fMRI) to assess the somatotopic cortical representation of the hands of workers subjected to occupational vibration. The study included six men with severe vibration exposures who were suffering from hand-arm-vibration syndrome (HAVS) and six controls. The analysis focused on the pattern and degree of activation of contra- and ipsilateral hemispheres of the brain with tactile stimulation and motor activation of the hand. These stimulations resulted in well-defined activation of the contralateral, and to a lesser extent the ipsilateral hemisphere. Statistical analysis of this limited patient material did not indicate any significant somatotopic cortical changes following long-term exposure to vibrating hand-held tools, although there was a tendency to a shift of activation towards the more cranial parts of the cortex in the patient group.

Brain plasticity and hand surgery: an overview

The hand is an extension of the brain, and the hand is projected and represented in large areas of the motor and sensory cortex. The brain is a complicated neural network which continuously remodels itself as a result of changes in sensory input. Such synaptic reorganizational changes may be activity-dependent, based on alterations in hand activity and tactile experience, or a result of deafferentiation such as nerve injury or amputation. Inferior recovery of functional sensibility following nerve repair, as well as phantom experiences in virtual, amputated limbs are phenomena reflecting profound cortical reorganizational changes. Surgical procedures on the hand are always accompanied by synaptic reorganizational changes in the brain cortex, and the outcome from many hand surgical procedures is to a large extent dependent on brain plasticity.

A model instrument for the documentation of outcome after nerve repair

We present a new model for documentation and quantification of the functional outcome after nerve repair at the wrist or distal forearm level and a protocol that includes a numerical scoring system. The model, presented here along with validation and reliability test results, supports our hypothesis that the summarized test results reflecting specific functional limitations correlates well with the patient's opinion of the impact of the nerve injury on activities of daily living. Seventy patients with nerve repair were examined using the protocol. Analysis included 3 factors: sensory domain (sensory innervation, tactile agnosis, and finger dexterity), motor domain (motor innervation and grip strength), and pain/discomfort domain (hyperaesthesia and cold intolerance). The analysis explained 73% of the variances of the variables and the variables had a logical distribution between the factors. Analysis of internal consistency demonstrated good homogeneity. A calculated total score correlated strongly with the patients' global estimation of the impact of the injury on activities of daily living and the summary of sensory and pain/discomfort domains correlated significantly with the Medical Research Council S0-S4 scale. The presented model represents a useful new tool for evaluation of the functional outcome after nerve injury and repair.

Evaluation and management of chronic work-related musculoskeletal disorders of the distal upper extremity

This clinical review will describe the epidemiology, clinical presentation, and management of the following work-related musculoskeletal disorders (WMSDs) of the distal upper extremity: deQuervain's disease, extensor and flexor forearm tendinitis/tendinosis, lateral and medial epicondylitis, cubital tunnel syndrome, and hand-arm vibration syndrome (HAVS). These conditions were selected for review either because they were among the most common WMSDs among patients attending the New York State Occupational Health Clinics (NYSOHC) network, or because there is strong evidence for work-relatedness in the clinical literature. Work-related carpal tunnel syndrome is discussed in an accompanying paper. In an attempt to provide evidence-based treatment recommendations, literature searches on the treatment of each condition were conducted via Medline for the years 1985-1999. There was a dearth of studies evaluating the efficacy of specific clinical treatments and ergonomic interventions for WMSDs. Therefore, many of the treatment recommendations presented here are based on a consensus of experienced public health-oriented occupational medicine physicians from the NYSOHC network after review of the pertinent literature. A summary table of the clinical features of the disorders is presented as a reference resource.