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Monitoring energy levels in chronic fatigue syndrome.

Thousands of Americans have become afflicted with a puzzling and debilitating disease called Chronic Fatigue Syndrome (CFS) (Bell, 1991; Fisher, 1987; Goldstein, 1990; Jason, Fitzgibbon, et al., 1993; Jason, Taylor, et al., 1993). The most prominent symptom is persistent fatigue for at least six months (Holmes et al., 1988).

One promising theory of the etiology of CFS is that any of a number of infectious agents might alter immune response in genetically vulnerable people. With the immune system affected, other viruses that are normally controlled begin to replicate. In an attempt to attack these viruses, the immune system produces cytokines (e.g., interleukin-2) and these substances cause side effects such as fatigue and muscle aches. The immune system remains in an activated mode to combat a continuing viral infection (Feiden, 1990; Landay, Jessop, Lennette, & Levy, 1991). Demitrack et al. (1991) found low levels of cortisol in CFS patients, which might be caused by a deficit of corticotropin-releasing hormone. Deficits in cortisol have been linked to lethargy and fatigue, and this deficit might be contributing to the overactive immune system.

Cohen and Williamson (1991) suggest there is a relation between stress and increased illness behavior. Manuck, Cohen, Rabin, Muldoon, and Bachen (1991) found that only individuals who showed heightened catecholamine and cardiovascular reactions to stress showed suppression in their immune function in response to a 20-minute laboratory stressor. Kasl, Evans and Niederman (1979) studied mononucleosis infection among cadets who were not immune to mononucleosis. Those who contracted the illness had fathers who were described as overachievers. The sons were very committed to a military career, but performed poorly academically, thus creating stress. These studies suggest that there might be many factors, including stress, susceptibility, and coping styles that cause people to become ill with infectious diseases.

The traditional medical establishment was initially skeptical of the existence of CFS. Some physicians believed that CFS patients were just depressed. CFS patients show more alpha EEG activity during NREM sleep, but this is not seen in dysthymic or major depressive disorders (Whelton, Salit, & Moldofsky, 1992). In addition, many CFS-afflicted people have no premorbid history of depression, and some of their viral and immunological indicators have not been found in people solely suffering from depression (Goldstein, 1990). A study by Straus, Fritz, Dale, Gould, and Strober (1993) found CFS patients had a smaller percentage of CD4 T cells, and their memory T cells expressed increased levels of adhesion markers. Adhesion markers help T cells attach to particular tissues. The increased number of memory cells with adhesion molecules appear to shift from the blood to the tissues, and these tissue-based cells escape detection by research blood tests. In the tissues, the increased number of memory cells with adhesion cells release molecules that regulate the immune response, and they can cause mild inflammation and pain. This might explain some of the complaints of CFS patients, including painful muscles and joints, and tender lymph nodes. Although many studies do indicate abnormalities in cellular immune response in CFS-afflicted people, many of these findings have not been consistently reproduced (Krupp, Mendelson, & Friedman, 1991).

Articles have been written describing the use of cognitive and psychological therapeutic techniques in overcoming CFS symptoms (Burke, 1992; Butler, Chalder, Ron, & Wessely, 1991; Friedberg & Krupp, 1994; Hayden, 1991; Lloyd et al, 1993; Rikard-Bell & Waters, 1992). In brief, attempts at recovery for CFS-affected people might profit from following a theory outlined by Kaplan (1991), which posits that immunosuppression can be modified by decreasing vulnerability (e.g., increasing coping and social support), adverse life experiences, and dysphoric responses. A variety of personal strategies (e.g., relaxation, meditation, and hypnosis) and environmental interventions (e.g., staying with friends and supportive families) might be employed to ameliorate this illness.

At the National Institute of Allergy and Infectious Disease/National Institute of Mental Health workshop on Chronic Fatigue Syndrome, a number of recommendations were made concerning the assessment of illness severity. The organizers of this conference suggested that the clinical evaluation should include a screening test for psychiatric distress and depression. In addition, they identified six domains of interest: fatigue, mood disturbance, functional status, sleep disorders, global well-being, and pain (Schluederberg et al., 1992). To measure functional disability, the Coop charts (Nelson, Landgraf, Hays, Wasson, & Kirk, 1990) have been used. In addition, the Medical Outcomes Study 36-item Short-Form Survey (Ware & Sherbourne, 1992), a reliable and valid measure, has been used to discriminate between gradations of disability. Others have mentioned the need for a neuropsychological test battery for CFS (Grafman, Johnson, & Scheffers, 1991). Jason and Taylor (1994) devised a series of rating scales that were used to show changes in CFS symptoms over time. Many of these above scales and tests have been used to measure CFS, but one of the more perplexing problems has been developing measures of fatigue and energy levels (Bell, 1991).

Huang and Quinlan (1989) calculated disability based on the patient's kilocalorie expenditure for the day, but this method requires a time-consuming accurate diary of daily activity. Barofsky and Legro (1991) reviewed a number of single item and multiple item scales to measure the degree of fatigue. For example, Krupp, LaRocca, Muir-Nash, and Steinberg (1989) used a seven-point Fatigue Severity Scale (1 signifies no fatigue, 7 severe fatigue) to measure medical problems, and this easy-to-use instrument has been used to assess CFS (Krupp et al., 1991). These scales typically have been used to provide a sample describing one time point of the fatigue construct; however, fatigue might best be understood as a perceived phenomenon that varies over the course of both brief and longer time periods.

Another strategy has been offered by Wood, Magnello, and Sharpe (1992), who repeatedly collected data on energy levels over time with a sample of CFS patients, and this type of ongoing assessment seems critical in order to understand symptoms that often appear and disappear for at times brief, and at other times, protracted periods of time. Wood et al. (1992) had CFS patients rate their levels of physical and mental energy, and positive and negative affect 6 times daily for 7 days. Unfortunately, levels of activity and symptoms other than energy were not rated. Fatigue might best be understood in its relation to activity level, because some CFS-afflicted individuals might experience little fatigue if they restrict their activities, whereas others might experience extreme fatigue with only minor or moderate activity.

The current U.S. definition of CFS is based on a set of symptoms (e.g., sore throat, unexplained generalized muscle weakness), which are scored using a binary classification (i.e., occurrence versus nonoccurrence). Given the importance of these symptoms, and particularly energy levels, in defining CFS, a more differentiated system that provides time series data might provide researchers a more sophisticated methodology for classifying CFS. Because fatigue levels are such a prominent and defining symptom of Chronic Fatigue Syndrome, a behavioral approach using time series methods will illustrate some of the possible advantages of using behavioral procedures in describing fatigue in CFS. Other behaviorists have also indicated the need for a general system model that routinely assesses multiple reponses over time, which help explain covariations in multiple measures (Delprato, 1992; Ray & Delprato, 1989). The purpose of the present study was to collect time series data on two subjects who had been diagnosed with Chronic Fatigue Syndrome.

Method and Results

Subject A

The individual studied had been sick with CFS for 2 years. Onset had been immediate, with a vital infection. When data were gathered, Subject A had returned to work on a part-time basis. Two independent physicians confirmed a diagnosis of Chronic Fatigue Syndrome, using the criteria of Holmes et al. (1988). Subject A had no preexisting psychiatric problems.

For 2 consecutive days, starting at 6:30 a.m. and lasting until 9:30 p.m., data were collected each hour using a written form that was provided to the subject. Subject A was provided an explanation of how to use the forms, but no prompts were provided during data collection. Data were collected hourly on two of the primary symptoms: feverishness (0=normal, 10=severe problem) and fatigue (0=normal, 10=severe problem). During each hourly period, the slight presence (1), or definite presence (2) of two moods (i.e., obsessing, calmness) were recorded. Any uplifts (desirable events; 1=minor, 2=moderate, 3=extreme) or hassles (undesirable events; 1=minor, 2=moderate, 3=extreme) were recorded. Finally, activity level (1=practically none, 10=excessive), which was defined as energy expenditure for walking, working, thinking, and so forth, was recorded hourly.

Figure 1 presents Subject A's data on the symptom variables, hassles, uplifts, and moods for 2 days, starting hourly at 6:30 a.m. Figure 2 presents activity level data for Subject A.

As indicated in Figure 1, the data suggest that as activity level increases, the intensity of symptoms increases. In addition, hassles and obsessions appeared to occur in the morning while the subject was at work. When activities decreased and Subject A rested or relaxed at home, the symptoms tended to decrease.

Subject B

Subject B had originally been diagnosed with mononucleosis. For the next two and a half years, Subject B's work history was sporadic, working for periods of time and then not being able to work for weeks or months. For the past year and a half, Subject B had left work permanently, and was diagnosed as having CFS by two physicians, using the Holmes et al. (1988) criteria. Subject B reported requiring about 15 hours of sleep per day, and exercise consisted of walking around the house or completing a necessary errand. Subject B reported that symptom intensity was partially reduced by taking Naprosyn, Fluconazol, and Cardizem. Figure 3 charts the hourly changes which occurred during one 24-hour period for two primary symptoms (e.g., fatigue and sore throat) and the presence of uplifts and type of mood.

Activity level was rated as compared to Subject B's typical premorbid activity level (0=premorbid level, 10=severely different from premorbid level) and was defined as energy expenditure for sitting, driving, thinking, and so forth. These symptoms, fatigue and sore throat, were rated on a 10-point severity scale (0=none, 10=severe). The type of moods were either calm, mild anxiety, or mild depression. Data were not available for the hours between 9 p.m. and 10 a.m. and again for the hours between 2 and 5 p.m. as the subject slept during these periods. As is evident from Figure 3, Subject B's symptoms were rated as severe at all time points, even though activity level was rather low. Subject B's data, therefore, were very distinct from Subject A.


The present study provides an approach that uses data over time to capture some of the energy fluctuations that occur in the CFS syndrome. Most current efforts to chart symptoms and energy levels have involved data collected at one time point (except for the work of Wood et al., 1992, and Jason & Taylor, 1994), and thus some of the complexities of the disease and their relation to other precipitous ongoing events have been obscured. Given the many symptoms in this complex disease and the changing nature of some of its symptoms, new time series approaches might be needed to better understand CFS.

The original working case definition of Chronic Fatigue Syndrome by Holmes et al. (1988) has two major criteria:

1. New onset of persistent or relapsing, debilitating fatigue or easy fatigability in a person who has no previous history of similar symptoms, that does not resolve with bed rest, and that is severe enough to reduce or impair average daily activity below 50% of the patient's premorbid activity level for a period of at least 6 months. 2. Other clinical conditions that may produce similar symptoms must be excluded . . . (p. 388)

In addition to these two major criteria, there are 11 minor symptoms. The reduction in activity level definition has been modified by the Centers for Disease Control to include a greater than 50% reduction in energy level (Gunn, Connell, & Randall, 1993). No guidelines have been provided for evaluating a greater than 50% reduction in activity level or energy level. Of most importance, as indicated in the present study, energy levels for Subject A fluctuated dramatically over time, and they were associated with activity level and mood. For Subject B, energy levels were consistently low, but there did appear to be some marginal relation between more activity and higher levels of fatigue. Collection of time series data might provide researchers with the clinical data to revise the Holmes et al. (1988) definition so that energy level takes into account these fluctuations that may occur as a result of activity level and mood.

Wood et al. (1992) found diurnal variation in patterns of energy, with maximum levels recorded between 10.00 h and 12.00 h. Each CFS-afflicted person probably has a different pattern. Subject A usually felt stronger in the morning, but after 3 hours of work at the office, symptoms of fatigue and fever increased. Fatigue ratings rose to moderate levels, and they decreased rapidly after resting. It is important to realize that one year earlier, Subject A was not able to do any work. In addition, during the first year of the illness, Subject A indicated fatigue levels were higher, and the levels remained high for longer periods of time. Fluctuations in energy levels were considerably less variable for Subject B. Possibly, as individuals begin to recover from CFS, they become more active and more variations in energy patterns occur.

Evans and Edgerton (1991) have found a significant decrease in the frequency of desirable events, a directional increase in undesirable events, and an increase in negative emotions during the 4 days prior to a cold onset. In the present study, for Subject A, it appeared that there was a slight relation between the onset of hassles and obsessing with increased symptoms. Wood et al. (1992) found that levels of energy did not correlate with negative affect. It is possible that a relation was not found because Wood et al. assessed the CFS patients only six times per day, and more frequent data collection is needed in order to show a relation. In addition, different CFS patients might show different patterns, and these might be hidden when data are collapsed across subjects. In the present study, it appears that when more activity occurred for Subject A, often at work, the subject encountered more undesirable events and began obsessing about them. The elevation of symptoms was halted after going home and resting.

An important question involves why moderate activity levels and low stress levels so dramatically increased the intensity of symptoms for Subject A. Possibly, the subject's body had not been able to eradicate one or more viruses, and thus was in a state of arousal with high levels of cytokines, which caused fatigue. Deficits in corticotropin-releasing hormone and cortisol might also have produced the lethargy and fatigue (Demitrack et al., 1991). It is also possible that the low levels of stress or exercise negatively influenced the subject's brain, which might have become hypersensitive to stress because cytokines had reduced the threshold for neuronal excitability (Goldstein, 1990). It is also possible that exercise, which raises the body temperature, might have increased the already high levels of cytokines, thus precipitating more fatigue (Locke & Colligan, 1987). Impairments in the muscle system might have also contributed to the fatigue (Archard, Bowles, Behan, Bell, & Doyle, 1988; Shepherd, 1990). Wong et al. (1992) suggest that reduced physical endurance might be caused by a defect of oxidative metabolism with a resultant acceleration of glycolysis in the muscles. Finally, dramatic increases in cytokines occur when people go to sleep, and because CFS-afflicted people already have elevated levels of these cytokines, further increases in these levels could produce sleep disorders, which then might have contributed to additional fatigue (Moldofsky, 1991). A promising treatment of CFS using Ampligen has allowed some previously bedridden patients to resume their normal lives. Patients most likely to respond to this therapy have had markedly elevated levels of interleuken 1 (Cotton, 1991). Because many of the above findings have not been consistently reproduced (David, Wessely, & Pelosi, 1991; Shafran, 1991), caution needs to be exercised in interpreting these studies.

Another explanation of these data is that Subject B had CFS, because high levels of fatigue were less related to activity and mood. On balance, it could be argued that Subject A had a psychiatric problem, because negative mood states occurred prior to increased fatigue. This latter explanation is not likely as the subject had been assessed by several medical and psychiatric personnel, and no psychiatric disorders were uncovered. Still, using a psychoneuroimmunology model, it is possible that activity and negative moods did affect energy levels, and it is likely that there are constant communications between the endocrine, nervous, and immune systems.

CFS is still a perplexing disorder requiring more research. Because much of the research in this area has been more biological in orientation (Feiden, 1990), there is a need for more research exploring the interactional, social, and psychological dimensions of this illness (Antoni et al., 1994; Ray, Weir, Stewart, Miller, & Hyde, 1993). Patterns of fatigue may vary considerably for CFS patients. The present time series data might help in understanding the complexity of fatigue, and how it either changes or does not change over short and long periods of time. The present study involved only two subjects, and therefore caution needs to be exercised in interpreting the findings until studies are conducted with larger samples for more extended periods of time.


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Author:Jason, Leonard A.; Holden, John; Taylor, Stephanie; Melrose, Harriet J.
Publication:The Psychological Record
Date:Sep 22, 1995
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