Health hazard among cash register operators and the effect of improved working conditions.

The health condition of female cash register operators in relation to their working conditions was investigated. A questionnaire study revealed that cash register operators more frequently complained of general fatigue, headache, sleeplessness, and low back pain than female office machine operators or other female workers. Dullness and pain in the shoulder, arm, hand, and fingers especially on the right side were characteristic of cash register operators. Physical examinations in 1973 showed that 31.3% of 371 cash register operators suffered from muscle rigidity or tenderness; 13 were severely afficted and, 69 operators had to be either laid off, reassigned to other jobs, or given shorter working hours. Occupational cervicobrachial disorders were suggested to have been caused by repetitive upper limb motions combined with static load, an unfavorable working environment, and mental stress. Implementation of some improvements including shorter operation time, worker rotation, and adoption of electronic registers proved effective in reducing the number of sufferers of cervicobrachial disorders found during the 1975 physical examinations. But the improvements were not effective enough to alleviate fatigue of the neck, shoulder, and back due presumably to sustaining upper limbs while operating the keyboard.     

Influence of Vibration on Motor Responses in the Upper Arm Muscles under Stationary Conditions and during Voluntary and Evoked Arm Movements under Limb Unloading Conditions

Locomotion of mammals, including humans, is based on the rhythmic activity of spinal cord circuitries. The functioning of these circuitries depends on multimodal afferent information and on supraspinal influences from the motor cortex. Using the method of transcranial magnetic stimulation (TMS) of arm muscle areas in the motor cortex, we studied the motor evoked potentials (MEP) in the upper arm muscles in stationary conditions and during voluntary and vibration-evoked arm movements. The study included 13 healthy subjects under arm and leg unloading conditions. In the first series of experiments, with motionless limbs, the effect of vibration of left upper arm muscles on motor responses in these muscles was evaluated. In the second series of experiments, MEP were compared in the same muscles during voluntary and rhythmic movements generated by left arm m. triceps brachii vibration (the right arm was stationary). Motionless left arm vibration led to an increase in MEP values in both vibrated muscle and in most of the non-vibrated muscles. For most target muscles, MEP was greater with voluntary arm movements than with vibration-evoked movements. At the same time, a similar MEP modulation in the cycle of arm movements was observed in the same upper arm muscles during both types of arm movements. TMS of the motor cortex significantly potentiated arm movements generated by vibration, but its effect on voluntary movements was weaker. These results indicate significant differences in the degree of motor cortex involvement in voluntary and evoked arm movements. We suppose that evoked arm movements are largely due to spinal rather than central mechanisms of generation of rhythmic movements.     

Primary central nervous system plasmablastic lymphoma presenting in human immunodeficiency virus-negative but Epstein-Barr virus-positive patient: A case report

ABSTRACT: We report a 32-year-old Outer Mongolian man, with plasmablastic lymphoma (PBL) primarily occured in the central nervous system and diagnosed by surgical resection. This patient appeared headache and Magnetic resonance imaging (MRI) showed multiple lesions in the right cerebral hemisphere including the right frontal-parietal lobe and right basal ganglia and the left cerebellum, he was diagnosed as lymphoma by stereotactic biopsy in January 2009 in local hospital, and was given radiotherapy 33 times after the biopsy. The patient was admitted to The Military General Hospital of Beijing PLA., Beijing, P.R. China on March 9th, 2011, with chief complaints of right limbs convulsioned suddenly, then fell down and lose of his consciousness, then awoke after 4 to 5 minutes, with symptoms of angulus oris numbness and the right upper limb powerless ten days ago. MRI of the brain revealed a well-defined hyperdense and enhancing mass in the left frontalparietal lobe, the meninges are closely related, there was extensive peritumoural edema noted with pressure effects, as evident by effacement of the left lateral ventricles and a 0.5 cm shift of the midline to the right side. Surgical resection showed markedly atypical, large singly dispersed or cohesive proliferation of plasmacytoid cells with frequent abnormal mitoses and binucleation, some neoplastic cells were large with round or oval nuclei and showed coarse chromatin and smaller or unapparent nucleoli, some neoplastic cells with prominent nucleoli, apoptosis and necrosis were often presented. Immunohistochemistry staining and gene rearrangement together with other supportive investigation confirmed the diagnosis of primary central nervous system plasmablastic lymphoma. A month later, he was started on chemotherapy with R-CHOP (rituximab, cyclophosphamide, doxorubicin, leurocristime and prednisone) for a week. Other supportive treatment was provided for symptomatic epilepsy. The patient regained muscle strength in both upper limbs and right lower limb and the symptomatic epilepsy was controlled after two weeks. Then the patient was discharged. Follow-up data shows the patient to be alive eleven months after discharge. Virtual Slides The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1649317674697046.     

Mitochondrial enzymes discriminate between mitochondrial disorders and chronic fatigue syndrome

We studied the extent of mitochondrial involvement in chronic fatigue syndrome (CFS) and investigated whether measurement of mitochondrial respiratory chain complex (RCC) activities discriminates between CFS and mitochondrial disorders. Mitochondrial content was decreased in CFS compared to healthy controls, whereas RCC activities corrected for mitochondrial content were not. Conversely, mitochondrial content did not discriminate between CFS and two groups of mitochondrial disorders, whereas ATP production rate and complex I, III and IV activity did, all with higher activities in CFS. We conclude that the ATP production rate and RCC activities can reliably discriminate between mitochondrial disorders and CFS.     

Health Survey of Numbness/Pain and Its Associated Factors in Kotohira,Japan

We conducted a survey of adults in Kotohira, a town of about 10,000 people located in the Nakatado District of Kagawa Prefecture, Japan. The survey was distributed to 8184 individuals, and effective responses were received from 3863 persons (response rate, 47.2%) during the survey period. Results regarding numbness and pain showed numbness alone in 7.7%, pain alone in 7.2%, both numbness and pain in 6.0%, and neither numbness nor pain in 79.6%. Spine and spinal cord damage was reported present by 5.4%, and absent by 94.6%. Analysis using the Short-Form Health Survey questionnaire, with comparison between subjects reporting both numbness and pain in the extremities and subjects with either numbness or pain alone, showed lower scores for in Short-Form Health Survey subscales (physical functioning, role [physical, emotional], bodily pain, vitality, and mental health). Subjects with numbness alone generally reported no disability in daily life. In a secondary survey, analysis of neurological findings by specialists identified 6 cases of “pain following spinal cord damage” in which spinal cord-related pain developed in the hands or feet. This represented 0.15% of the survey population starting from the primary survey.     

Roberts syndrome: study of 4 new Rgyptian cases with comparison of clinical and cytogenetic findings

Roberts syndrome is a rare autosomal recessive genetic disorder (MIM 268300). It is characterized by pre and postnatal growth retardation, severe shortening of limbs with radial defects, oligodactyly and characteristic facial features. The present study reports 4 new cases of Roberts syndrome from 3 families presenting variable phenotypes. Patients were thoroughly investigated clinically and cytogenetically. By reviewing literature, we compared our cases to those previously reported. The rating severity system proposed by Van den Berg and Francke (30) was applied to correlate the phenotypic and cytogenetics changes. We observed more severe reduction defects in the upper limbs than in the lower limbs. While the main reduction defects in the upper limbs involved the thumb and radius ranging to phocomelia, absent or severely hypoplastic fibula was the main lower limb involvement. We emphasize this finding in the present investigation. Heterochromatin repulsion of chromosomes derived from Roberts syndrome patients is a characteristic cytogenetic abnormality. It was a constant finding in our studied patients demonstrated by DABI stain which supports the possibility that mutations in Roberts syndrome lie in centromere related proteins which may also play a role in body patterning. This was proved recently by Vega et al. (31). Application of the clinical rating score and its correlation with cytogenetic changes showed negative results. Cytogenetic studies in normal obligatory heterozygotes parents showed no changes. Phenotypic variability within the same family as well as between different families was observed. The ascertainment of 4 cases with Roberts syndrome from 3 Egyptian consanguineous families during one year in our department may indicate a high frequency of the Roberts syndrome allele among Egyptians. This confirms the need for molecular studies for early and accurate prenatal diagnosis to prevent such dramatic malformation syndrome.     

Odontostomatologic management of patients receiving oral anticoagulant therapy: a retrospective multicentric study

Background

Neurologically, it is proven that stimulation of larger diameter fibers - e.g. using appropriate coldness, warmth, rubbing, pressure or vibration- can close the neural "gate" so that the central perception of itch and pain is reduced. This fact is based upon "Gate-control" theory of Melzack and Wall.

Presentation of the hypothesis

Syringe Micro Vibrator is a new design being introduced for the first time in the field of Dentistry. This device is a promising breakthrough in pain and anxiety management and may deliver solution for clinicians plagued with patient pain phobia. It has an off-set rotating micro vibration creator with ultra high frequency and ultra low altitude that can be easily placed on any standard dental syringe and some disposable syringes. This device was registered as an invention in dentistry and received Iran National Patent number of 63765.

Testing the hypothesis

By creating micro vibration, this device would be effective in reducing the pain and anxiety confronted with most types of intraoral injections as palatal, mandibular block, intraligamental and local infiltration. From the aspect of the patient pain management, this device contributes both physiologically (based on Gate Control Theory of pain) and psychologically (based on the device function as will be explained by dentist to the patient as a modern pain reducing technology). From the aspect of clinician, SMV motor provides vibrations with ultra high frequency to alleviate pain, but since it has ultra low vibration altitude, it has no adverse effect on the clinician dexterity and accuracy during injection and it does not interfere with pin point localization of injection site.

Implications of the hypothesis

Upon mounting on a conventional dental anesthesia injection syringe, SMV is switched on and the clinician then uses normal injection technique to administer the anesthetic. This device is not only a useful accessory device for ordinary patients, but also more useful for pediatric patients and those who have a phobia of intraoral injection or pain.     

丹蛭降糖胶囊联合硫辛酸、依帕司他对气阴两虚夹瘀型糖尿病周围神经病变患者血糖水平和下肢神经功能的影响

摘要 目的：探讨丹蛭降糖胶囊联合硫辛酸、依帕司他治疗气阴两虚夹瘀型糖尿病周围神经病变（DPN）的临床疗效,并分析其对血糖和下肢神经功能的影响。方法：按照随机数字表法将81例DPN患者分成对照组40例和观察组41例,对照组在2型糖尿病治疗基础上使用硫辛酸静滴联合依帕司他口服治疗,观察组在对照组治疗基础上,加用丹蛭降糖胶囊口服治疗。比较两组治疗前后中医证候积分、双下肢肌电图[腓总神经运动神经传导速度（MCV）、腓肠神经感觉神经传导速度（SCV）]、电流感觉阈值（CPT值）、血糖指标[空腹血糖（FPG）、餐后2小时血糖（2 hBG）、糖化血红蛋白（HbA1c）]水平变化,并对比两组总有效率和治疗方案安全性。结果：观察组总有效率为90.24%（37/41）,明显高于对照组的70.00%（28/40）,差异有统计学意义（P＜0.05）;治疗8周后,两组肢体麻木、肢体末梢疼痛、神疲乏力、气短懒言、腰膝酸软、失眠烦躁积分,FPG、2 hBG、HbA1c水平均明显降低（P＜0.05）,且观察组各项中医证候积分和血糖指标水平均明显低于对照组（P＜0.05）;治疗8周后,观察组相同频率正弦交流电刺激下的第一脚趾远端趾节甲小皮基部近端的CPT值均明显低于对照组（P＜0.05）,腓总神经MCV、腓肠神经SCV均明显高于对照组（P＜0.05）;两组治疗过程中均未发生明显药物不良反应。结论：丹蛭降糖胶囊口服联合硫辛酸、依帕司他治疗气阴两虚夹瘀型DPN,能够有效缓解患者的临床症状和体征,控制血糖水平,改善下肢神经功能,疗效明显优于单纯西药治疗,且安全性高。     

Guillain-Barré syndrome following bacterial meningitis: a case report and literature review

Background

We reported a case of an adult that presented Guillain-Barré syndrome (GBS) after bacterial meningitis which was secondary to chronic suppurative otitis media (CSOM). To our knowledge, this is the first case involving an adult presenting with GBS following bacterial meningitis.

Case presentation

A 46-year man with type 2 diabetes and otitis media (OM) suffered with fever, headache, and vomiting for 6?days. The patient’s neck stiffness was obvious and the Kernig and Brudzinski signs were produced. The result of cerebrospinal fluid (CSF) analysis and cytological examination of the CSF supported the diagnose of bacterial meningitis. On day 17 the patient felt numbness in both hands and feet, which gradually progressed to weakness of the limbs. Bladder dysfunction occurred, which required catheterization. The patient showed a tetraparesis with emphasis on the legs. The deep tendon reflexes of limbs were absent. The patient had peripheral hypalgesia and deep sensory dysfunction. The symptoms were possibly a result of GBS. Nerve conduction study showed that the F wave latency of the upper and lower limbs was prolonged, particularly the lower limbs. 8?days later the repeated nerve conduction study showed a low compound muscle action potential (3.3?mV) with a normal distal motor latency (14.2?ms) and a low motor nerve conduction velocity (34.3?m/s) in the tibial nerve. The patient still required assistance when walking 3 months after onset.

Conclusions

GBS following bacterial meningitis is rare and limbs weakness in patients with bacterial meningitis was usually considered because of weakness. This case should serve as a reminder for clinical doctors that when a patient with bacterial meningitis complains about limbs numbness or weakness, GBS should be considered, especially when the patient had diabetes mellitus (DM) history.

     

Self-reported symptoms associated with exposure to electromagnetic fields: a questionnaire study

In the last years, it has been discussed frequently whether there are any harmful effects of electromagnetic fields on human health. Electromagnetic fields are generated by several natural and man-made sources. Part of the electromagnetic spectrum called Radiofrequency is used in communication systems such as mobile (cellular) phone and computer. The aim of our study was to explore different self-reported symptoms that may be associated with exposure to electromagnetic fields. This survey study was conducted, using a questionnaire, on 350 people aged +9 years in Turkey. The chi-square test was used for data analysis. Self-reported symptoms were headache, vertigo/dizziness, fatigue, forgetfulness, sleep disturbance-insomnia, tension-anxiety, joint and bone pain, lacrimation of the eyes, hearing loss and tinnitus. As a result of the survey, the study has shown that users of mobile phone and computer more often complained of headache, joint and bone pain, hearing loss, vertigo/dizziness, tension-anxiety symptoms according to time of daily usage (p?p?相似文献   

三维旋进式振动疗法联合常规康复训练对脑卒中偏瘫患者上下肢痉挛状态、步行能力及生活质量的影响

摘要 目的：探讨三维旋进式振动疗法联合常规康复训练对脑卒中偏瘫患者上下肢痉挛状态、步行能力及生活质量的影响。方法：按照随机数字表法,将南京医科大学附属苏州医院2020年4月~2022年4月期间收治的80例脑卒中偏瘫患者分为对照组（常规康复训练）和实验组（三维旋进式振动疗法联合常规康复训练）,每组各40例。对比两组偏瘫侧上下肢痉挛状态、步行能力及生活质量情况。结果：两组干预4周后、干预8周后Fugl-Meyer运动功能评分（FMA）上肢、下肢评分均较干预前升高,且实验组高于对照组（P<0.05）。两组干预4周后、干预8周后步长、步速、6 min步行试验（6MWT）均较干预前升高,且实验组高于对照组（P<0.05）。两组干预8周后,生理职能（RP）、活力（VT）、生理功能（PF）、总体健康（GH）、社会功能（SF）、躯体疼痛（BP）、情感职能（RE）、精神健康（MH）均较干预前升高,且实验组高于对照组（P<0.05）。结论：三维旋进式振动疗法联合常规康复训练应用于脑卒中偏瘫患者,可有效改善上下肢痉挛状态,提高步行能力,促进生活质量提高。     

The cubital tunnel syndrome caused by intraneural ganglion cyst of the ulnar nerve at the elbow: a case report

Background

Cubital tunnel syndrome is common nerve compression syndrome among peripheral nerve compression diseases. However, the syndrome caused by intraneural ganglion cysts has been rarely reported. Medical approaches, like ultrasound-guided aspiration and open surgical treatment remain to be discussed.

Case presentation

A 57-year-old woman presented with occasional pain, numbness and paralysis in her left hand and a palpable, painless mass in the ulnar side of her left elbow. Ultrasound-guided aspiration of the mass was performed to decompress the ulnar nerve. The patient experienced an evident release of pain in her hand, but symptoms of numbness and paralysis recurred 3 months later which greatly bothered the patient’s daily life. After evaluation, we had to perform an open surgery to excise the cyst. External neurolysis and anterior subcutaneous transposition were done. The patient was followed up for 2 years, and she made a complete recovery with no functional limitation.

Conclusions

The symptoms caused by intraneural ganglion cyst can be alleviated by accurate puncture. But puncture may be not complete and symptoms could recur. Complete external neurolysis can be counted as a complete and reliable treatment. Therefore, early diagnosis, careful preoperative imaging assessment and full decompression can be expected to receive a good rehabilitation.

     

沙格雷酯治疗2型糖尿病伴下肢动脉硬化闭塞症患者的疗效评估

目的:探讨沙格雷酯治疗2型糖尿病伴下肢动脉硬化闭塞症(ASO)患者的临床疗效。方法:选择2014年4月~2015年5月我院2型糖尿病伴下肢ASO患者80例,给予口服沙格雷酯100 mg,3次/日,连续8周,监测治疗前后患肢的症状与体征、双下肢动脉峰值血流速度、血糖、血脂及血液流变学等指标的变化。结果:口服沙格雷酯8周后,患者疼痛感、冷感、间歇性踱行、麻木感及下肢溃疡等主观症状有效率均大于91%,临床总有效率为93.75%。治疗后患者左、右下肢动脉血管直径与治疗前比较,差异无统计学意义(P0.05),但左、右下肢动脉峰值血流速度比治疗前显著降低,差异有统计学意义(P0.05)。治疗后患者的甘油三酯、总胆固醇、低密度脂蛋白、全血高切黏度及全血低切黏度比治疗前降低,差异有统计学意义(P0.05)。结论:沙格雷酯可改善2型糖尿病伴下肢ASO患者的症状,降低双下肢动脉峰值血流速度,临床疗效确切,值得临床推广应用。     

The Effects of Vibration and Muscle Fatigue on Trunk Sensorimotor Control in Low Back Pain Patients

Introduction

Changes in sensorimotor function and increased trunk muscle fatigability have been identified in patients with chronic low back pain (cLBP). This study assessed the control of trunk force production in conditions with and without local erector spinae muscle vibration and evaluated the influence of muscle fatigue on trunk sensorimotor control.

Methods

Twenty non-specific cLBP patients and 20 healthy participants were asked to perform submaximal isometric trunk extension torque with and without local vibration stimulation, before and after a trunk extensor muscle fatigue protocol. Constant error (CE), variable error (VE) as well as absolute error (AE) in peak torque were computed and compared across conditions. Trunk extensor muscle activation during isometric contractions and during the fatigue protocol was measured using surface electromyography (sEMG).

Results

Force reproduction accuracy of the trunk was significantly lower in the patient group (CE = 9.81 ± 2.23 Nm; AE = 18.16 ± 3.97 Nm) than in healthy participants (CE = 4.44 ± 1.68 Nm; AE = 12.23 ± 2.44 Nm). Local erector spinae vibration induced a significant reduction in CE (4.33 ± 2.14 Nm) and AE (13.71 ± 3.45 Nm) mean scores in the patient group. Healthy participants conversely showed a significant increase in CE (8.17 ± 2.10 Nm) and AE (16.29 ± 2.82 Nm) mean scores under vibration conditions. The fatigue protocol induced erector spinae muscle fatigue as illustrated by a significant decrease in sEMG median time-frequency slopes. Following the fatigue protocol, patients with cLBP showed significant decrease in sEMG root mean square activity at L4-5 level and responded in similar manner with and without vibration stimulation in regard to CE mean scores.

Conclusions

Patients with cLBP have a less accurate force reproduction sense than healthy participants. Local muscle vibration led to significant trunk neuromuscular control improvements in the cLBP patients before and after a muscle fatigue protocol. Muscle vibration stimulation during motor control exercises is likely to influence motor adaptation and could be considered in the treatment of cLBP. Further work is needed to clearly identify at what levels of the sensorimotor system these gains are achievable.     

A hip abduction exercise prior to prolonged standing increased movement while reducing cocontraction and low back pain perception in those initially reporting low back pain

Persons who develop low back pain from prolonged standing exhibit increased muscle cocontraction, decreased movement and increased spine extension. However, it is unclear how these factors relate to pain development. The purpose of this study was to use hip abductor fatigue to manipulate muscle activity patterns and determine its effects on standing behaviours and pain development. Forty participants stood for two hours twice, once following a hip abductor fatigue exercise (fatigue), and once without exercise beforehand (control). Trunk and gluteal muscle activity were measured to determine cocontraction. Lumbo-pelvic angles and force plates were used to assess posture and movement strategies. Visual analog scales differentiated pain (PDs) and non-pain developers (NPDs). PDs reported less low back pain during the fatigue session, with females having earlier reductions of similar scale than males. The fatigue session reduced gluteal and trunk cocontraction and increased centre of pressure movement; male and female PDs had opposing spine posture compensations. Muscle fatigue prior to standing reduced cocontraction, increased movement during standing and reduced the low back pain developed by PDs; the timing of pain reductions depended on spine postures adopted during standing.     

Upper extremity impairment in workers performing repetitive tasks.

A series of subjective and objective measures were chosen to determine impairment of upper extremity function in 157 workers performing repetitive tasks. Workers were asked to respond to questions regarding their perception of the presence or absence of numbness, pain, weakness, or swelling in their upper extremities. Objective tests consisted of the measurement of grip strength, pinch strength, Semmes-Weinstein monofilament sensory responses, vibrometer responses, neurometer measurement, and the presence or absence of Tinel's or Phalen's signs. These measures were considered collectively to estimate the overall levels of impairment of each individual. Overall findings show that 55 percent of workers examined had impairment scores of 2 or more and 75 percent had scores of 1 or more. Significant differences were found in impairment ratings between job types. Those jobs requiring the highest repetition with the least rest per cycle had the highest impairment ratings. Workers that rotated jobs had impairment scores significantly less (p less than 0.005) than the average of workers performing single-task jobs. We conclude that cumulative trauma disorders are more prevalent than originally believed and that the disorder is best examined from an overall functional impairment perspective.     

EMG recurrence quantifications in dynamic exercise

This study was designed to evaluate the suitability of nonlinear recurrence quantification analysis (RQA) in assessing electromyograph (EMG) signals during dynamic exercise. RQA has been proven to be effective in analyzing nonstationary signals. The subject group consisted of 19 male patients diagnosed with low back pain. EMG signals were recorded from left and right paraspinal muscles during isoinertial exercise both before and after 12 weeks of regimented physical therapy. Autorecurrence analysis was performed between the left and right EMG signals individually, and cross-recurrence analysis was performed on the left-right EMG pairs. Spectral analysis of the EMG signals was employed as an independent, objective measure of fatigue. Increase in the RQA variable % determinism during the 90-s dynamic tests was found to be a good marker for fatigue. Before physical therapy, this nonlinear marker revealed simultaneous increases in motor unit recruitment within each pool and between left and right pools. After physical therapy, the motor unit recruitment was less within and between pools, indicative of increased fatigue resistance. Finally, fatigue resistance (less increase in % determinism) correlated well with subjective scores of pain relief. Taken together, these latter results indicate that recurrence analysis may be useful in charting the efficacy of a specific exercise therapy program in reducing low back pain by elevating the fatigue threshold.     

Tissue vibration in prolonged running

The impact force in heel–toe running initiates vibrations of soft-tissue compartments of the leg that are heavily dampened by muscle activity. This study investigated if the damping and frequency of these soft-tissue vibrations are affected by fatigue, which was categorized by the time into an exhaustive exercise. The hypotheses were tested that (H1) the vibration intensity of the triceps surae increases with increasing fatigue and (H2) the vibration frequency of the triceps surae decreases with increasing fatigue. Tissue vibrations of the triceps surae were measured with tri-axial accelerometers in 10 subjects during a run towards exhaustion. The frequency content was quantified with power spectra and wavelet analysis. Maxima of local vibration intensities were compared between the non-fatigued and fatigued states of all subjects. In axial (i.e. parallel to the tibia) and medio-lateral direction, most local maxima increased with fatigue (supporting the first hypothesis). In anterior–posterior direction no systematic changes were found. Vibration frequency was minimally affected by fatigue and frequency changes did not occur systematically, which requires the rejection of the second hypothesis. Relative to heel-strike, the maximum vibration intensity occurred significantly later in the fatigued condition in all three directions. With fatigue, the soft tissue of the triceps surae oscillated for an extended duration at increased vibration magnitudes, possibly due to the effects of fatigue on type II muscle fibers. Thus, the protective mechanism of muscle tuning seems to be reduced in a fatigued muscle and the risk of potential harm to the tissue may increase.     

A two alternative forced choice method for assessing vibrotactile discrimination thresholds in the lower limb

The development of an easy to implement, quantitative measure to examine vibration perception would be useful for future application in clinical settings. Vibration sense in the lower limb of younger and older adults was examined using the method of constant stimuli (MCS) and the two-alternative forced choice paradigm. The focus of this experiment was to determine an appropriate stimulation site on the lower limb (tendon versus bone) to assess vibration threshold and to determine if the left and right legs have varying thresholds. Discrimination thresholds obtained at two stimulation sites in the left and right lower limbs showed differences in vibration threshold across the two ages groups, but not across sides of the body nor between stimulation sites within each limb. Overall, the MCS can be implemented simply, reliably, and with minimal time. It can also easily be implemented with low-cost technology. Therefore, it could be a good candidate method to assess the presence of specific deep sensitivity deficits in clinical practice, particularly in populations likely to show the onset of sensory deficits.     

Electromyographic changes in work-related myalgia of the trapezius muscle.

In 11 patients, all women, 21-55 years of age, with unilateral work-related myalgia of the trapezius muscle, the right and left trapezius muscles were examined simultaneously for electromyogram (EMG) signs of localized muscle fatigue. All patients were tested with 0-kg hand load for 5 min, holding the arms straight at 90 degrees of elevation in the scapular plane. Only 4 of the patients tolerated exposure to higher load levels. They were tested with 1 kg hand load for 3 min and 2 kg hand load for 2 min, with a period of rest of 30 min between the trials. The EMG mean power frequency (MPF) and root mean square (rms) were calculated. Data were normalized with the initial value as a reference and regression analyses were performed. On both sides a decrease of MPF and an increase of rms were found with increasing time and load, i.e. classical EMG signs of localized muscle fatigue. Compared with the nonaffected side smaller changes were found on the affected side, possibly due to pain inhibition, impaired microcirculation and biochemical changes along the muscle fibres. At 0-kg hand load we found no change of MPF on either side despite subjective feelings of fatigue and pain. We interpreted these findings as an indication of reduced capacity of the affected trapezius muscle to sustain static load with early development of pain-associated local fatigue.