Every year a large number of people come down with computer-related repetitive stress syndrome (RSI), causing
employers millions of dollars worth of damages. When these patients visit doctors, convention medical opinion is that too much typing has caused their hand-problems. The syndrome, alternatively termed cumulative trauma disorder, is vaguely defined by its symptoms of pain, tingling, numbness, weakness, really any condition of the upper body extremities. Is too much typing really causing all of these problems? A diseases is not a cluster of symptoms, it is an underlying pathology that leads to symptoms. Etiology, not symptoms, makes a specific disease what it is. In this paper I will examine critically the evidence that computer use causes hand problems and explore the possibility that RSI is a somatic syndrome. In order to determine the association between risk factors and disease both should be well defined; so we ask what is “repetitive stress”? Some conditions, such as carpal tunnel syndrome, have a defined pathogenesis and can be measured objectively with a variety of tests. Work-related musculoskeletal disorders (a neutral term for RSI that does not imply causation) have amorphous symptoms such as hand pain that are not easily quantifiable, nor is there a clear anatomical basis for the symptoms. Keyboarding may be extremely repetitive, but it only involves small amounts of force; nevertheless, there has been an epidemic of lost workdays due to alleged upper extremity repetitive stress injuries. Sixty percent of the 92,500 cases of upper extremity injury in 1999 were due to injury of unclear origins, thought to be repetitive stress injuries and such injuries have accounted for a comparable deluge of lawsuits. Interestingly, the lawsuits have not resulted in awards for the plaintiff’s, a highly unusual result in our pro-torte judicial
system. We will examine what the medical community has determined about RSI and what the courts have ruled. In the general population the occurrence of carpal tunnel is the same whether or not people perform repetitive activities, so we can hypothesize that RSI, if it exists, must be distinct from carpal tunnel and have a specific causation of its own. Two researchers, Barsky and Borus, consider repetitive stress injury to be a functional somatic syndrome characterized by a variety of symptoms and suffering, rather than a disease characterized by tissue abnormality. Let us look at the specific case of an Australian telecommunications company to illustrate the likely somatic roots of RSI. The company employed 90,000 workers and presumably of these workers, some percent had carpal tunnel, unrelated to typing. The incidence of disease should rise and fall in correspondence with risk factors for the disease. Let’s look at the incidence of RSI. In 1983 the rate of RSI began to rise, it peaked in 1984 and by 1987 was down to its 1983 levels. Now that may not sound like unusual variance, but the magnitude of the difference between 1983 and 1984 over a large population, is highly unlikely. From 1983 to 1984, the incidence increased by more than 30 times its original rate. It returned to its original rate in 1987 with no appreciable changes in typing patterns. Now let’s look at physiological data to support the theory that RSI is a somatic syndrome. The keyboard operators complained of pain; the objective clinical findings identified random tenderness. No consistent pattern of pain emerged. Individual’s pain failed to conform to any known neurological pathway, anatomical structure, or physiological pattern. The patients failed to respond to any form of physical treatment in a statistically significant way. RSI could not be shown to have a relationship with
keystroke rate, age, nor job duration. In a study of 229 patients from the Australian company, 29 were diagnosed with specific diseases such as carpel tunnel. Of the remaining 200 all had some anxiety, irritability or lowering of mood, many had other psychological symptoms such as sleep disturbances all reported that treatment for RSI was ineffective. Cooper vs. the Commonwealth, in which the Australian Supreme Court found the employer not guilty of negligence and that the plaintiff had not been injured may have been the single factor that decreased the incidence of RSI in Australia the most. America has also experienced a large number of product liability cases alleging an array of upper extremity injury and disease, predominantly carpal tunnel and repetitive stress injury, as results of typing. The steering committee for the National Academy of Sciences Workshop on Work-Related Musculoskeletal Disorders attempted to characterize the state of evidence that physical factors can cause musculoskeletal disorders. They concluded “Strong associations between measured biomechanical stressors at work and musculoskeletal disorders were observed; however, temporal contiguity between the stressors and onset of effects, as well as evidence of amelioration after reduction of stressors could not always be established.” In other words, typists may get RSI but there is no causal relationship. The committee also said “published studies that show associations between biomechanical stressors and musculoskeletal disorders are difficult to interpret because of the possibility that plausible but unmeasured factors could explain all of the observed differences in rates of musculoskeletal disorders. In other words, whether biomechanical stressors or something else have caused higher rates of musculoskeletal disorders could not be definitively answered.”1 The courts came to
Szabo RM, King KJ: Repetitive stress injury: diagnosis or self-fulfilling prophecy?
similar conclusions. In 1997, a group of plaintiffs went to trial in a mass consolidation of cases against one particular keyboard manufacturer. Once again, the claim of a link between typing and injury did not hold up. The jury unanimously can down in favor of the defendant and to-date no one has succeeded in litigation against a computer-keyboard manufacturer. If typing is not the cause of unspecified musculoskeletal disorders, what is? Recall the hypothesis that musculoskeletal disorders are somatic syndromes. Researchers have had trouble trying to find a correlation between typing and musculoskeletal disorders. Some pieces of evidence, such as the delayed onset of RSI, no direct increase in RSI with increased intensity or frequency of typing and a lack of relief from stopping typing, make it harder to support a theory of causal relationship between typing and RSI. If we look at other characteristics of people who get work-related musculoskeletal disorders some trends become clearer. Researchers have correlated monotonous work, a perceived high workload, time pressure, and lack of social support with musculoskeletal symptoms.
Certain characteristics span and unite sufferers of all functional somatic
syndrome. Some hypothesize that it is medical specialization that has differentiated these syndromes and that a substantial overlap exists between the individual syndromes and that the similarities between them outweigh the differences. Scientists can observe objective abnormality in diseases. RSI has no objective pathology, only patients’ subjective experiences of symptoms, causing it to be categorized as a somatic syndrome. RSI fits the definition the functional somatic profile in as medically inexplicable in terms of a conventionally defined disease resulting from pathology. The prevalence of
emotional distress and disorder in patients who attend hospital with functional syndromes is higher than in patients with comparable medical conditions such are carpal tunnel. These patients are not making up their symptoms, nor are they hypochondriacs. Many are severely disabled and conventional medical therapy is ineffective for them. A new disease paradigm is needed to treat RSI and other functional somatic syndromes. Functional somatic syndromes are amplified by medicalization. Patients, once diagnosed, experience an exacerbation of symptoms and suffering because of the validation of their “disease” and assumption of the “sick” role because the sickness is portrayed as catastrophic and disabling. Other functional somatic syndromes include multiple-chemical sensitivity, chronic fatigue, and irritable bowel syndrome. Altered central nervous system function has been implicated in many functional somatic syndromes. Psychotherapy, antidepressant drugs, and emphasis of rehabilitation at the expense of cure have all been shown to increase recovery rates from functional somatic syndromes. Convincing the patient that he or she is not critically ill may be just important; these diseases are not “all in the patient’s head” they are originating from the patient’s head. To explain the point that the illness may be psychological in nature but physiologically exhibited we will focus in again on RSI. In RSI, decreased blood flow to the hands and upper extremity due to the body’s interpretation of possible injury there may be causing the damage. A study that measured vascular response to muscular work in the radial artery in patients with the diffuse arm pain characteristic of RSI found that the radial artery is relatively constricted and fails to dilate with exercise. They also showed decreased blood flow and colder than average arms. Thus, it appears that diffuse
forearm pain is due to a physiological claudication (lameness) of the muscle. This physiological symptom is not the result of a disease, caused by a self-perpetuating pain condition. An explanation of the constriction is inhibition of local endothelial nitric oxide function (the thin layer of cells that line blood vessels are dilated by NO). In the study of blood flow, we once again saw the common feature of stress, often work related, before onset and all participants could not continue with their work due to their RSI. It is hypothesized that the disability and progressive pain is a result of biofeedback set into a cycle of pain. Patients have developed RSI after a specific arm injury or prolonged use and fatigue. We can hypothesize that the body cut off blood flow to protect the arm and tell the patient to decrease activity and that this became a cycle of pain and progressive reduction in blood flow. The original feeling may have come from typing, but it is the short circuit in feedback and continued constriction that likely causes the disease. It is hypothesized that the cycle can be triggered by worrying about risk at the onset of symptoms and thus causing constriction after relatively harmless fatigue if the patient has heard of RSI. Perhaps the best cure for RSI and other somatic syndromes will be to continue to research the body’s feedback mechanisms and to educate about functional somatic syndromes, not the terrible debilitation caused by their symptoms.