A cross-sectional study of the relation between symptoms and physical findings in computer operators

Abstract

BackgroundThe character of upper limb disorder in computer operators is subject to debate. A peripheral nerve-involvement is suggested from the common presence of a triad of symptoms consisting of pain, paraestesiae and subjective weakness, and from physical findings suggesting neuropathy. This study aimed to examine the outcome of a detailed neurological examination in computer operators and to compare findings with the presence of symptoms.Methods96 graphical computer operators answered a modified Nordic Questionnaire including information on perceived pain in the shoulder, elbow, and wrist/hand scored for each region on a VAS-scale 0 – 9. In addition, they underwent a physical examination including the subjective assessment of the individual function of 11 upper limb muscles, of algesia in five and vibratory threshold in three territories, respectively, and of mechanosensitivity of nerves at seven locations. In order to reflect an involvement of the brachial plexus (chord level), the posterior interosseous nerve and the median nerve at elbow level we defined three patterns of neurological findings illustrating the course of nerves and their innervation. The pain scores summarized for the three upper limb regions (min. = 0, max = 27) in the mouse-operating and contralateral limbs were compared by a Wilcoxon test and the relation to each physical item analyzed by Kendall's rank correlation. The relation of summarized pain to each pattern was studied by application of a test of the trend across ordered groups (patterns).ResultsPain, paraestesiae and subjective weakness was reported for 67, 23, and 7 mouse-operating limbs, respectively, with the summarized pain scores exceeding 4 in 33 limbs. Abnormal physical findings were prevalent. The summarized pain was significantly related to a reduced function in five muscles, to mechanical allodynia at one location and to elevated threshold to vibration in two territories. Brachial plexopathy was diagnosed in 9/2, median neuropathy in 13/5 and posterior interosseous neuropathy in 13/8 mouse operating/contralateral limbs, respectively. The summarized pain was significantly higher in the mouse-operating limbs and in limbs with any of the defined patterns. There was a significant trend between the summarized pain and the summarized scores for the items contained in each pattern.ConclusionThis small-scale study of a group of computer-operators currently in work and with no or minor upper limb symptoms has indicated in symptomatic subjects the presence of peripheral nerve-afflictions with specific locations.

Pathophysiology of non-specific arm pain

“…3,17 In a study of 96 intensive computer users (67 of whom had mild upper limb pain), pin prick hyperalgesia was noted in 40 computer mouse operating limbs while 60 computer mouse operating limbs were found to have mechanical allodynia. 17 Touch evoked allodynia has also been noted in 58% of participants with NSAP. 3 A number of studies have reported abnormal neural mechanosensitivity in NSAP.…”

Work-Related Upper Limb Pain and Its Diagnosis: Contribution from the Neurological Examination

“…Application of the same physical examination in upper limb patients in the primary health sector [11], and in occupational risk groups [12,17] identified similar disorders displaying the same physical neurological abnormalities.…”

“…The significance of this approach is evident from previous studies [10][11][12]. As an example, one third of a series of 82 pronator syndromes in 73 patients had previously undergone carpal tunnel decompression without remission and the remaining patients were given various other diagnoses.…”

“…Using this approach indicated that upper limb peripheral nerve afflictions were frequently responsible for work-related upper limb pain in the majority of the examined upper limb patients in a hospital based clinic of occupational medicine [10], general practice [11], and occupational groups such as computer operators [12]. The infraclavicular part of the brachial plexus, the posterior interosseous nerve at the edge of the supinator muscle, and the median nerve at elbow level were the most common locations of nerve afflictions, and these locations were often combined in the same limb [7,8,10].…”

Applications of the Standardized Nordic Questionnaire: A Review

“…Jepsen and Thomsen [206] examined the effect on the nervous system in the arms of workers who used the computer mouse and found problems of nerve transmission in three areas of the upper arm. Arvidsson et al [208] also found musculoskeletal problems in the elbow and hand of the right arm as a consequence of using the computer mouse in air controllers.…”