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RESEARCH REPORTS

Descriptive Report of the Impact of Fatigue and Current Management Strategies in Cerebral Palsy

Brunton, Laura K. PT, PhD

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doi: 10.1097/PEP.0000000000000490
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Fatigue is a common secondary impairment associated with cerebral palsy (CP)12 and may be related to changes or declines in physical function, including the cessation of walking.3 Adolescents and adults with CP reportedly experience greater fatigue than the general population.4–7 Estimates vary, with 18% to 39% of adults with CP (aged 16-80 years) experiencing fatigue related to CP. Those who are fatigued have between 12% and 41% severe fatigued, as measured by a Fatigue Severity Scale (FSS) score of 5.1 or more.5–7 The FSS was developed to measure fatigue of people with multiple sclerosis and systemic lupus erythematosus. The scale has 9 questions rated on a 7-point Likert scale.8 The FSS has not been validated for use with people with CP. Studies have used the FSS to provide evidence that fatigue is an issue for people with CP, as it is a quick tool and has been used for people who have other neurological conditions. The FSS has limitations; for example, it does not measure self-perceived severity of fatigue. It fails to adequately describe the effect that fatigue may have on a person's life. Finally, the FSS lacks descriptive information about possible targets for intervention or methods that may be useful in managing fatigue.

There are numerous published fatigue scales that have been used with people with neurological conditions; however, until recently there was no fatigue measure validated for use with people with CP. As a result, the Fatigue Impact and Severity Self-Assessment (FISSA) was specifically created and validated for use with people with CP to address the shortcomings of other measurement tools.9 The FISSA was created with specific intentions both to identify people with CP-related fatigue and to facilitate discussions between people with CP, families, and clinicians about possible management strategies to mitigate the effect of fatigue on daily activities.9 The FISSA is a comprehensive self-report questionnaire of 37 items created from a literature review, qualitative interviews with people with CP, and focus groups with health care providers.9 The first 31 questions are scored using a 5-point Likert scale from 1 (completely disagree) to 5 (completely agree),9 with the exception of items 13 to 17, which are scored on different scales, as they relate to levels of fatigue experienced or amount of time fatigue is experienced. There are 2 subscales: the Impact subscale, with questions on the effect and severity (items 1-17) and the Management and Activity Modification subscale, with items on possible strategies for mitigating fatigue or consequences of fatigue (items 18-31).9 There are 6 questions that are not scored as part of the measure but ask about diurnal fatigue and open-ended questions about self-management of fatigue for intervention planning.9 These questions provide a useful starting point for a conversation about fatigue management (items 32-37).9

An impact score is the sum of the first 17 items in the Impact subscale (including the severity profile) and a separate management score summing the remaining items (items 18-31 in the Management and Activity Modification subscale).9 The sum of 31 items is a total fatigue score representing fatigue experienced—considering effect, severity, and individual management. The FISSA is a valid and reliable tool for assessing fatigue in people with CP, and it defines fatigue as “physical tiredness, muscle soreness, exhaustion of your muscles and body or any related feeling.”9 Discrimination between groups expected to have more fatigue based on functional ability and pain experiences is evidence of construct validity.9 The FISSA has adequate test-retest reliability intraclass correlation coefficient (3,1) = 0.74 (95% confidence interval, 0.53-0.87).9

The purpose of this study is to describe the effect of fatigue and self-management of adolescents and young adults with CP. The primary objective is to describe and compare responses to the questions on the Impact subscale and the Management and Activity Modification subscale of the FISSA between 2 functionally defined groups: participants in Gross Motor Function Classification System (GMFCS)10 level I and those in GMFCS levels II to V.

METHODS

This was a descriptive cross-sectional study in which a total of 367 youth and young adults with CP were contacted by regular post or electronic mail as part a larger study. 8 Participants were recruited from children's rehabilitation centers in Ontario, Canada, previous research studies, preexisting Facebook groups for people with CP, and through an advertisement in the Ontario Federation for Cerebral Palsy Web site and newsletter. Eligibility criteria included aged 14 to 31 years, with a diagnosis of CP (self-reported), who were English speaking, and had the ability to complete self-report questionnaires with a degree of independence. Surveys completed entirely by parental proxy were excluded from the study. The mailing contained the FISSA, a self-report version of the GMFCS-Extended and Revised Version,11 to describe the functional abilities of respondents (self-report version available from https://www.canchild.ca) and a demographic questionnaire used to obtain self-reported distribution of impaired body regions, age, sex, and information regarding the amount of assistance required to complete the survey. The study used a modified Dillman approach,12 in which participants were contacted either 2 or 3 times depending on their participation. All potential participants initially received a full survey package (or an e-mail with the letter of information and survey link) containing a $10 gift card or code as an incentive to participate. In an effort to increase the number of respondents, a reminder letter was mailed to each potential participant approximately 2 weeks following the initial package mailing. All participants who had not returned the survey 2 weeks after the reminder letters were sent a second, complete questionnaire package 4 weeks following the initial mailing. Staff members at the children's rehabilitation centers facilitated the mailing of surveys and reminder letters as per their recruitment policies. The investigator facilitated mailing for participants recruited from other sources. All returned questionnaires were anonymous through the use of a study ID number. This study received approval from the ethics review boards at Western University, McMaster University, and specific clinical sites as appropriate. Returning a completed questionnaire was considered implied consent to participate in this study.

As a result of the small number of participants in each GMFCS level, they were grouped together to increase the subgroup sample size. Two groups were created. The first group consisted of participants at GMFCS level I (walk without limitations). The second group consisted of participants at GMFCS level II (walk with limitations), level III (walk using a hand-held mobility device), level IV (use powered mobility due to limitations in self-mobilization), and level V (without the ability to self-mobilize).11 These 2 groups were based on previous substudies of the same dataset that indicated that the total fatigue (FISSA) score was not different among those with ambulatory limitations (GMFCS levels II-V), but those groups were significantly different from those in level I.9,13 In a previous study with this dataset, the FISSA scores (Impact subscale and Management subscale scores) differed by the preidentified GMFCS grouping.13 In the current study, descriptive analysis of the survey responses was completed using the Pearson χ2 for each question based on the 2 groups, with a Bonferroni correction to account for the multiple comparisons

RESULTS

We received returns from 163 participants of the 367 people contacted (response rate of 44%). Thirty-three returned questionnaires were excluded from analysis because they were returned blank, were from people who did not meet eligibility criteria, or were completed entirely by parental proxy. An additional 6 participants failed to report their GMFCS level and were unable to be grouped for analysis. The final convenience sample consisted of 124 adolescents and young adults with CP (response rate of 34%) who returned a questionnaire completed at least semi-independently (independent completion or having had some assistance completing the questionnaire). Participant demographics are shown in Table 1.

TABLE 1 - Participant Characteristics and Demographic Information of the Sample
Characteristic Total (n = 124) n (%)
Sexa
Male 58 (47)
Female 65 (53)
Age
Mean (SD), y 18.7 (4.5)
Median 17
Range 14-31
GMFCS level
I 34 (27)
II 39 (32)
III 21 (17)
IV 18 (14)
V 12 (10)
Distribution of involvementb
Monoplegia 6 (5)
Hemiplegia 31 (25.5)
Diplegia 44 (36)
Triplegia 10 (8)
Quadriplegia 31 (25.5)
Abbreviations: GMFCS, Gross Motor Function Classification System; SD, standard deviation.
aOne participant did not report his or her sex.
bTwo participants did not report distribution of involvement.

Table 2 provides the frequency of responses by group for each item on the Impact subscale, and Table 3 provides this information for each item on the Management and Activity Modification subscale of the FISSA.

TABLE 2 - Frequency Responses Between Functional Groups for the Impact Subscalea
Response Option Item (Impact Subscale) Completely Disagree Somewhat Disagree Neither Agree nor Disagree Somewhat Agree Completely Agree P Value
GMFCS I, % GMFCS II-V, % GMFCS I, % GMFCS II-V, % GMFCS I, % GMFCS II-V, % GMFCS I, % GMFCS II-V, % GMFCS I, % GMFCS II-V, %
1. Fatigue interferes with my general everyday activities 32.4 10.0 47.1 15.6 11.8 10.0 5.9 45.6 2.9 18.9 <.001b
2. Fatigue interferes with my ability to move around indoors 64.7 20 29.4 15.6 2.9 12.2 2.9 38.9 0 13.3 <.001
3. Fatigue interferes with my ability to do things on my own 67.6 16.7 11.8 13.3 14.7 18.9 2.9 31.1 2.9 20.0 <.001
4. Fatigue interferes with my ability to move around in my community 47.1 18.9 26.5 12.2 20.6 20.0 2.9 25.6 2.9 23.3 <.001
5. Fatigue interferes with my ability to get outside of my house 73.5 26.7 14.7 13.3 5.9 18.9 2.9 25.6 2.9 15.6 <.001
6. Fatigue interferes with my ability to finish things 38.2 12.2 20.6 7.8 14.7 14.4 23.5 45.6 2.9 20.0 .001
7. Fatigue interferes with my participation in social activities 47.1 17.8 26.5 10.0 11.8 17.8 14.7 36.7 0.0 17.8 .001
8. Fatigue interferes with my ability to start things 55.9 21.3 20.6 13.5 2.9 18.0 17.6 38.2 2.9 9.0 <.001
9. Fatigue interferes with my ability to take care of myself 82.4 31.8 8.8 11.4 2.9 25.0 2.9 18.2 2.9 13.6 <.001
10. I use adaptive equipment to manage my fatigue 93.8 32.6 6.3 1.1 0.0 12.4 0.0 14.6 0.0 39.3 <.001
11. I have had to reduce my work responsibilities outside of my home because of fatigue 75.8 35.6 6.1 6.7 12.1 18.9 3.0 24.4 3.0 14.4 .001
12. I have had to reduce my responsibilities at home because of fatigue 75.0 40.0 6.3 8.9 9.4 25.6 9.4 18.9 0.0 6.7 .015
Abbreviation: GMFCS, Gross Motor Function Classification System.
aItems 13 to 17 are not presented in this article, as they represent the severity of fatigue and are scaled differently from the rest of the Fatigue Impact and Severity Self-Assessment items; these results have been published separately.14
bStatistically significant results are italicized.

TABLE 3 - Frequency Responses Between Functional Groups for the Management and Activity Modification Subscale
Response Option Item (Management Subscale) Completely Disagree Somewhat Disagree Neither Agree nor Disagree Somewhat Agree Completely Agree P Value
GMFCS I, % GMFCS II-V, % GMFCS I, % GMFCS II-V, % GMFCS I, % GMFCS II-V, % GMFCS I, % GMFCS II-V, % GMFCS I, % GMFCS II-V, %
18. Fatigue interferes with my enjoyment of life 52.9 28.9 20.6 20.0 14.7 17.8 11.8 18.9 0.0 14.4 .044
19. Fatigue interferes with my leisure and recreational activities 41.2 13.3 17.6 14.4 14.7 14.4 23.5 38.9 2.9 18.9 .004
20. Fatigue interferes with the length of time I can be physically active 26.5 4.4 14.7 5.6 8.8 4.4 23.5 33.3 26.5 52.2 .001a
21. Fatigue interferes with my balance and coordination 23.5 5.6 14.7 9.0 14.7 13.5 26.5 25.8 20.6 46.1 .015
22. Fatigue interferes with my motivation to do physical activities 20.6 11.4 29.4 17.0 14.7 8.0 26.5 34.1 8.8 29.5 .053
23. Fatigue interferes with my motivation to participate in social activities 52.9 19.5 14.7 13.8 8.8 17.2 20.6 29.9 2.9 19.5 .003
24. My muscles ache when I am fatigued 20.6 8.0 14.7 8.0 8.8 10.2 26.5 30.7 29.4 43.2 .205
25. Long periods of inactivity increase my fatigue 29.4 18.2 17.6 8.0 8.8 23.9 35.3 23.9 8.8 26.1 .026
26. Stress increases my fatigue 20.6 13.6 14.7 6.8 29.4 10.2 17.6 23.9 17.6 45.5 .008
27. Fatigue increases my stress 20.6 14.8 20.6 6.8 23.5 23.9 14.7 23.9 20.6 30.7 .151
28. I pace my physical activities to manage my fatigue 32.4 17.8 8.8 7.8 20.6 28.9 23.5 31.1 14.7 14.4 .467
29. I think about fatigue when I plan my day 61.8 44.4 11.8 20.0 11.8 12.2 11.8 12.2 2.9 11.1 .365
30. I limit my physical activity to manage my fatigue 44.1 26.1 11.8 14.8 26.5 22.7 11.8 27.3 5.9 9.1 .220
31. I stop and rest during activity to manage my fatigue 36.4 21.1 6.1 4.4 15.2 11.1 27.3 27.8 15.2 35.6 .197
Abbreviation: GMFCS, Gross Motor Function Classification System.
aStatistically significant results are italicized.

Scores on Impact subscale items were significantly different (P < .004) between the groups (items 1-11; P < .001 for items 1-5 and 8-10; P = .001 for items 6, 7, and 11) except for item 12 “I have had to reduce my responsibilities at home because of fatigue” (P = .015).

Significant differences on the Management and Activity Modification subscale between groups were only evident in the questions related to fatigue interference with the length of time someone could be physically active (item 20; P = .001) and with motivations to participate in social activities (item 23; P = .003). Participants in GMFCS level I were almost equally split on their thoughts about fatigue interference with the length of time they could be active physically; 41% disagreed with this statement and 50% agreed that fatigue impacted the length of physical activity sessions. Of the participants in levels II to V, 85% agreed that fatigue limited the length of physical activity sessions. Sixty-eight percent at GMFCS level I disagreed that fatigue impacted their motivation for social interaction, and 49% of at GMFCS levels II to V felt fatigue did have an effect on motivation to participate in social activities. The remaining items on the fatigue Management and Activity Modification subscale were not significantly different between the 2 groups. Despite the difference in effect of fatigue between the 2 groups, participants in both groups equally disagreed with statements that they use specific management strategies.

DISCUSSION

Participants in GMFCS level I reported little effect of fatigue on their general activities, independence, self-care, and mobility activities. However, participants in GMFCS levels II through V did report significant effect of fatigue on their general activities, independence, and mobility. Only 32% of those in GMFCS levels II to V agreed that fatigue impacted their ability to perform self-care activities, likely representing some differences between GMFCS levels contained within this larger grouping. Similarly, about half the participants in levels II to V reported that they used adaptive equipment to manage fatigue.

Based on the observed differences on items contained in the Impact subscale, the overall effect of fatigue is greater for participants with more functional limitations. The lack of differences between groups on the items related to strategies used to mitigate fatigue is not surprising, given the lack of interventions aimed at fatigue management for all people with CP in the current health care climate. Many studies have reported the presence of fatigue in people with CP, but there are currently no evidence-based interventions for fatigue management for people with CP. Fatigue management strategies such as pacing, planning, resting, and activity modification were discussed by participants in a qualitative study regarding the bodily experience of CP and were therefore included as explicit questions in the Management and Activity Modification subscale of the FISSA to facilitate a better understanding of the strategies used by youth with CP.15 In the current study, resting was the most commonly employed strategy, with 56% of the sample reporting that they stop and rest to mitigate fatigue levels. The next most used strategy was pacing; however, less than half (44% of total sample) of the participants reported using this strategy. Finally, planning was the least common fatigue management strategy used by participants. Approximately 70% of participants reported not thinking about fatigue when planning their day. The lack of significant differences for many of the items on the Management and Activity Modification subscale of the FISSA combined with the known difference in effect of fatigue suggests that we are not doing enough to help manage fatigue for people with CP. Pacing, planning, resting, and activity modification should be integrated into clinical conversations about fatigue management to address the overwhelming effect and individualized experience of fatigue reported by youth with CP. Only 30% of participants reported limiting their physical activity to manage fatigue. This result is promising, as it is thought that increasing physical activity levels may be useful for managing fatigue,14,16,17 although the specific relationship between physical activity and fatigue remains unknown. Observations from the current study in combination with previously published research related to fatigue in people with CP support the complexity of the relationship between fatigue and physical activity and highlight the need to better understand the relationship.

Further exploration of many of the remaining Management and Activity Modification subscale items suggests variability in responses that reinforce the highly individualized presentation of CP and may provide opportunities for increased clinical guidance for fatigue management. For example, many participants felt that additional stress in their lives increased their fatigue levels (item 26), or the reverse that experiencing fatigue was stressful (item 27), while others did not agree with these statements. Clinicians could explore stress-reducing strategies for people who agree with these items on the FISSA as a potential fatigue management intervention. Similarly, motivation to participate in physical (item 22) and social activities (item 23) was variable, as was the effect of fatigue on participation in leisure and recreation activities (item 19). Variability in responses within and across functional ability levels may represent the value that different participants placed on being social, physically active, or the enjoyment they receive from participating in leisure activities and could be potential targets for intervention.

The FISSA is a tool that can initiate or guide conversations in alignment with current practices using shared management approaches to care.9 The FISSA may provide a better understanding of the variable nature of fatigue in people with CP, and as it pertains to a specific client. For example, in the current study, approximately half the sample (49%) felt that long periods of inactivity increased their fatigue. In the clinic, the Canadian 24-hour movement guidelines18 or the recently published physical activity guidelines for people with CP19 could be used as educational tools to facilitate conversations about fatigue management. Clinicians might suggest small, manageable bouts of physical activity to decrease sedentary behaviors and mitigate fatigue for people who agree with this item on the FISSA.

As another example, the participants in the current study were overwhelmingly in agreement that fatigue can interfere with balance and coordination (item 21). Clinicians know that when balance and coordination are affected there may be an increased risk of a fall and/or injury that may affect functional status. Therefore, adequate fatigue management, ideally self-awareness and self-management of fatigue guided by a rehabilitation clinician, may reduce the negative health consequences of falls or unintentional injuries and contribute to greater overall health and well-being.

Early identification of fatigue and timely intervention should be a health promotion goal that rehabilitation professionals discuss with families throughout the adolescence. Given the effect that fatigue can have on functional status in adulthood,3 we need to use the supportive care models provided in the pediatric health care setting. Early recognition and intervention are more feasible during childhood and adolescence, because the supports that exist for people transitioning into adulthood are variable or often nonexistent.

Limitations

This study used a convenience sample that may have resulted in a selection bias. It is possible that participants experiencing fatigue were more likely to respond to a survey about fatigue, and this could have resulted in an overestimation of the fatigue experienced by the population with CP. In addition, the treatment centers used to identify potential participants required an internal staff member to facilitate the survey mailing. As a result, the investigator did not have access to descriptors for people who did not respond to the survey mailing and was therefore unable to determine whether the characteristics of responders and nonresponders were different. This could affect the generalizability of the findings from this study. The small sample size prevented the possibility of analyzing the GMFCS levels independently and required collapsing levels II to V into a single group.

Future Directions

Given the paucity of knowledge about fatigue in people with CP, more research is needed. Future studies should focus on identifying the age of onset and peak age of fatigue effect and severity. These outcomes should be tracked during growth and development. Studies with are needed with larger sample sizes and power to detect differences at each GMFCS level. A better understanding of self-manage for fatigue in the context of daily life supports participation in life roles. Finally, interventions to address fatigue need to be developed, implemented, and evaluated, as there are currently no evidence-informed fatigue management practices.

CONCLUSIONS

This is the first reporting of descriptive information on fatigue experienced by people with CP using a valid measure. Fatigue had a higher effect for participants with more functional limitations. The absence of observed differences between groups on the Management and Activity Modification subscale may be due to the lack of available fatigue management strategies, regardless of functional ability level. There is a need to explore and understand the causes, effect, and severity of fatigue and provide meaningful and relevant fatigue interventions. Fatigue is a commonly reported cause of functional deterioration; better prevention and management could increase the quality of life for all ages and functional ability levels.

ACKNOWLEDGMENTS

The author thanks Dr Doreen Bartlett for her support of and guidance on this project and her careful review of this article.

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Keywords:

adolescents; cerebral palsy; fatigue; young adults

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