Vegard Strøm

Work-induced pain, trapezius blood flux, and muscle activity in workers with chronic shoulder and neck pain

ABSTRACT Pain, trapezius microcirculation, and electromyography (EMG) were recorded during 90 min of simulated office work with time pressure and hand precision demands in 24 full‐time working subjects with chronic shoulder and neck pain. The responses were compared with those of a reference group of 28 healthy subjects without pain. Pain intensity was rated on a visual analogue scale. Intramuscular blood flux was measured by laser‐Doppler flowmetry (LDF) and muscle activity by surface EMG bilaterally in the upper trapezius. Pain increased during the work task, and the increase was larger in women than in men and in the reference group. Muscle activity was low: <4% of EMG during maximal voluntary contraction. LDF showed elevated intramuscular blood flux above baseline throughout the work task in both groups and during recovery in the pain group. Pain in the active side correlated positively with blood flux in the pain‐afflicted subjects and negatively in the reference group. In conclusion, office work induced pain, and trapezius vasodilation that did not return to resting values during recovery. These data show that pain is associated with trapezius vasodilation but not with muscle activity. Interaction between blood vessels and nociceptors may be important in the activation of muscle nociceptors in people with chronic shoulder and neck pain. Pain‐afflicted people may benefit from breaks spaced at shorter intervals than those needed by pain‐free subjects when working under time pressure.

Pain induced by a single simulated office-work session: Time course and association with muscle blood flux and muscle activity

The present study aimed to assess the development of pain during computer work with high precision demand and time pressure, and the association between pain and muscle blood fluxes and muscle activity. Twenty‐eight healthy subjects (range 22–44 years) performed a 90‐min standardized task of correcting a text on a word‐processor. Monetary reward was given according to productivity in order to induce time pressure. Pain intensity, general tension, and eye strain were reported on visual analogue scales before, during and after the computer session. Intramuscular trapezius blood fluxes were recorded by laser‐Doppler flowmetry (LDF) and analyzed as % of baseline level. Muscle activity was measured from the upper trapezius and forearm extensors by surface electromyography (EMG), analyzed as % of a maximal calibration contraction, %EMGmax. Pain, tension, and eye strain increased considerably during the computer session with different time course for pain and tension. The LDF of the active side of trapezius was elevated for 30min followed by a falling trend. There was an initial short‐lasting increase in the inactive trapezius. The upper trapezius EMG was low (<3 % of EMGmax) but increased during the work, similar in both the active and passive side. There was a significant time and blood flux interaction effect on pain in the shoulders/neck, but no association with EMG. In conclusion, considerable neck/shoulder pain may develop in healthy pain‐free subjects during 90min of office‐work and seems to be related to the regulation of trapezius muscle blood flow.

Pulmonary function, working capacity and strength in young adults with Marfan syndrome.

OBJECTIVE To investigate pulmonary function, working capacity and isokinetic muscle strength in subjects with Marfan syndrome. MATERIALS AND METHODS Seventeen subjects, mean age 23 years, performed spirometry, maximal ergometer cycle tests and knee extension and flexion isokinetic torque tests. RESULTS The subjects with Marfan syndrome had increased total and residual lung volume values compared with predicted values in healthy subjects and reduced peak oxygen uptake compared with healthy subjects of the same age. The isokinetic peak torque was reduced only at the highest velocity in the women. CONCLUSION Thirteen subjects were able to perform the bicycle test until exhaustion without cardiovascular complications or pulmonary restrictions. However, their aerobic capacity was considerably decreased, which we suggest is caused by deconditioning. Further investigations are needed to reveal how pulmonary and cardiovascular limitations change with ageing and to give guidelines for exercise.

Study Protocol of the International Spinal Cord Injury (InSCI) Community Survey

Objective The Learning Health System for Spinal Cord Injury (LHS-SCI) is an initiative embedded in the World Health Organizations (WHOs) Global Disability Plan and requires the statistical collection of data on the lived experience of persons with SCI to consequently formulate recommendations and policies. The International Spinal Cord Injury (InSCI) community survey has been developed as an initial step to gain information about the lived experience of persons with SCI within and across diverse nations. Design InSCI is a multinational community survey based on the International Classification of Functioning, Disability and Health Core Sets for SCI and involves 28 countries from all six WHO regions. The study will be implemented in 2017. Overall aims, guiding principles on sampling strategies, data collection modes, and reminder management are described. Conclusions InSCI will be the first survey to be conducted simultaneously in many countries and in all six WHO world regions that identifies the factors associated with functioning, health, and well-being of persons living with SCI. Expected results of the survey will be used for the basis of conducting stakeholder dialogs for policy reforms designed to improve the functioning, health maintenance, and well-being of persons with SCI.

People with Spinal Cord Injury in Norway

EPIDEMIOLOGY OF SPINAL CORD INJURY IN NORWAY In 2014,122 new cases of spinal cord injury (SCI) were registered in the Norwegian Spinal Cord Injury Registry (NorSCIR), of which 80 were traumatic and 42 were nontraumatic. Written consent is obtained from the participants before entering data into the registry, and permission is only requested from SCI patients submitted to a specialized SCI unit in Norway. Such permissions are obtained from 91% to 93% of the relevant patients. Data from 419 individuals are included for the period 2011–2014: 250 with a traumatic SCI and 169 with a nontraumatic SCI. Historical data on incidence and prevalence of SCI in Norway are relatively sparse. In 1974–1975, the incidence of traumatic SCI was reported to be 16.5. For the period 1952–2001, it was found to be 13.9 in western Norway. Thus, a relatively stable trend is found during the past 50 to 60 years. The etiology of SCI, based on the 2014 data from NorSCIR, are nontraumatic causes, 34.4%; traumatic causes due to falls, 29.5%; sports, 13.9%; transport, 13.1%; other traumatic, 8.2%; and assault, 0.8%. The main causes of traumatic SCIs have been unchanged for the past 50 years, except for an increasing trend toward higher incidence of fall-induced SCI among persons older than 50 years. People with traumatic SCI have an increased mortality rate (1.85) compared with the Norwegian population. Women with SCI have a significant higher mortality rate than men.

Deep tissue hyperalgesia after computer work

Abstract Background and purpose A growing number of people are using computers. Shoulder and neck pain occur commonly during computer work. Peripheral and central sensitization may play a major role in establishing and maintaining several chronic pain conditions. We have previously reported that a 90 min simulated computer office-work induced substantial pain in the shoulders and neck. We hypothesized that the development of pain during the computer work may be related to sensitization. The aim of the present study was to examine if the 90 min computer work induced deep tissue muscle hyperalgesia manifested as altered pressure pain thresholds (PPTs). Methods Twenty-two subjects with chronic shoulder and neck pain (pain group) and 26 healthy and pain free subjects (reference group) performed a standardized computer office-work task with use of a computer-mouse and with time pressure and high precision demands continuously for 90 min. The pressure pain threshold was measured with a pressure algometer in shoulder and forearm muscles (bilaterally in upper trapezius and extensor carpi radialis), and at sternum, before and 15 min and 30 min after the computer work task. Results The PPTs before starting the computer work were not different between the groups at any of the five locations. In both groups, the PPTs in the active and inactive side of the upper trapezius as well as in the extensor carpi radialis of the forearm operating the computer mouse were significantly reduced after the 90 min computer work compared with the pre-work levels. In the pain group, also the PPT in the inactive resting forearm was significantly reduced. The changes seen in PPTs from pre-to post-work were not significantly different between the groups, except for the inactive resting forearm where the groups exhibited different time course. Conclusion A decrease in pressure pain thresholds of involved muscles suggests that computer office-work can induce deep tissue hyperalgesia within 90 min. The development of pain during the computer work indicates peripheral sensitization as the predominant mechanism. Decreased pressure pain thresholds also in sites distant from pain areas may indicate a contribution from central sensitization in the subjects with chronic shoulder and neck pain. Implications The lasting pain after work and the reduced PPTs both in involved and distant musculature may indicate need for frequent pauses during computer work, especially when performed with time pressure and high precision demands, in order to avoid pain to increase and sustain after work, and thus to prevent the possibility of pain to become chronic.

Reliability of three-dimensional kinematic gait data in adults with spinal cord injury:

Objectives Three-dimensional gait analysis has been recommended as part of standardized gait assessment in people with spinal cord injury. The aim was to investigate inter- and intra-session reliabilities of gait kinematics in people with spinal cord injury. Methods Fifteen adults with spinal cord injury performed two test sessions on separate days. Six infrared cameras, 16 reflective markers and the Plug-in gait model were used. For each subject, five gait trials from both sessions were included. The Gait Profile Score and the Gait Variable Score were used as kinematic outcome measures. Reliability was assessed with intraclass correlation coefficient, standard error of measurement, minimal detectable change, and Bland–Altman plots. Results Inter-session intraclass correlation coefficient for all variables was >0.82 and standard error of measurement <1.8°, except for hip rotation. Intra-session reliability was found to be high (≥0.78) and slightly better than that for inter-session. Minimal detectable change for all variables was <4.7°, except for hip rotation. Conclusions The high inter- and intra-session reliabilities indicate small intrinsic variation of gait. Thus, three-dimensional gait analysis seems to be a reliable tool to evaluate kinematic gait in adults with spinal cord injury, but caution is warranted especially for hip rotation evaluation.

Coffee intake and development of pain during computer work

BackgroundThe present study sought to determine if subjects who had consumed coffee before performing a simulated computer office-work task found to provoke pain in the neck and shoulders and forearms and wrists exhibited different time course in the pain development than the subjects who had abstained from coffee intake.FindingsForty eight subjects all working fulltime, 22 with chronic shoulder and neck pain and 26 healthy pain-free subjects, were recruited to perform a computer-based office-work task for 90 min. Nineteen (40%) of the subjects had consumed coffee (1/2 -1 cup) on average 1 h 18 min before start. Pain intensity in the shoulders and neck and forearms and wrists was rated on a visual analogue scale every 15 min throughout the work task.During the work task the coffee consumers exhibited significantly lower pain increase than those who abstained from coffee.ConclusionsSubjects who had consumed coffee before starting a pain provoking office work task exhibited attenuated pain development compared with the subjects who had abstained from coffee intake. These results might have potentially interesting implications of a pain-modulating effect of caffeine in an everyday setting. However, studies with a double blind placebo controlled randomized design are needed.