The current study examined the frequency, severity, and course of a number of symptoms reported by adults with CP and their association with psychosocial functioning. Pain, fatigue, imbalance, and weakness emerged as the most common and most severe symptoms reported in this sample. All eight symptoms under study were more often reported to have either stayed the same or worsened than to have improved or resolved over time. Moreover, the symptoms—memory loss in particular—were more closely related to social integration than to other domains of community integration and psychological functioning. The results of this study provide new information about the experience of adults living with CP and have important implications for the assessment and treatment of symptoms in these patients.
As hypothesized, and consistent with previous reports [9
], almost three-quarters of participants in this study reported the presence of pain. These findings highlight the need for ongoing pain assessment in adults with CP. Previous research and our own clinical experience indicate that these patients are at risk for having their pain inadequately assessed; this may be due to factors such as patient communication and cognitive difficulties [44
], as well as provider biases and knowledge deficits [45
]. It is important that pain assessment in adults with CP be tailored to the individual patient. For example, a standard numeric rating scale or visual analog scale may be appropriate for relatively high functioning individuals, whereas a scale depicting facial expressions (e.g., Faces Pain Scale [46
]) may be preferred for those with cognitive impairments. A significant-other rating scale may be necessary for patients who lack the capacity to provide such self-report information, although observation or significant other ratings should not replace patient self-report when patients are able to describe their experience [47
In addition to its prevalence, both the severity and refractory nature of pain in the current sample was notable. These findings are consistent with the few previous studies that examined pain in adults with CP. Jensen et al. found relatively similar rates of moderate-to-severe pain in a sample of 50 adults with CP who were followed over a 2-year period [48
]. Interestingly, despite using many different types of pain treatments (e.g., over-the-counter and prescription medication, physical activity/exercise, application of heat and ice) over the course of the study and the fact that these treatments were rated as providing at least a moderate amount of pain relief, the average pain intensity reported by the participants in this study was largely unchanged over time [48
]. Engel et al. also investigated pain-related healthcare utilization in this population and found that a variety of pain treatments and healthcare providers were sought and used by study participants [35
]. Moreover, although many of the interventions were rated as being helpful, only a small subset of the sample reportedly accessed these services [35
]. Taken together, this emerging body of research points to a critical need for the development and provision of more effective treatments for pain in adults with CP.
The specific frequency and course of the other seven symptoms that were assessed in this study have received relatively little empirical attention to date. This is a conspicuous gap in the literature as indicated by the current findings; many of these symptoms were quite prevalent, severe, and refractory in nature. Specifically, more than half the sample reported fatigue, imbalance, and/or weakness, all of which were noted to have stayed the same or gotten worse over time. While it might be tempting to view these three symptoms as largely interchangeable—indeed, few investigations have considered them independently—we believe this would be unwise for several reasons. As a matter of measurement, these symptoms shared, at most, only 21 percent of their variances, suggesting that the study participants did in fact consider these symptoms to be distinct from one another. Moreover, a given patient could certainly experience balance problems—perhaps as a consequence of vestibular dysfunction [49
]—while still maintaining a normal level of strength and energy. Thus, although it is possible that fatigue, imbalance, and weakness are experienced concurrently by many individuals with CP, it is important that both clinicians and researchers assess the presence and severity of the three symptoms separately.
Previous research has found fatigue and weakness to be common in individuals with CP and related to various indices of physical and psychological functioning [13
]. Weakness, in particular, was significantly associated with social functioning in the current sample, which is not surprising, since one would expect that individuals experiencing weakness would find it especially challenging to engage in social activities, particularly those that occur outside the home. Given the many positive physical and emotional benefits associated with satisfying social relations [50
], providers may want to pay specific attention to the management of weakness in their patients with CP. Research has shown that interventions aimed at reducing weakness in this patient group can be quite effective [54
Research on balance problems among individuals with CP has typically focused on children (e.g., Burtner et al. [55
]) rather than adults. The current study, however, suggests that such problems are quite prevalent and severe in adults with CP. A recent longitudinal study by Scandinavian investigators also highlighted the importance of balance integrity in this population [56
]. In that study, 149 adults with CP were followed over 7 years to determine changes in walking function. The results indicated that changes in balance were the most frequently reported determinants of changes in walking ability over time [56
]. Additional research is needed that examines the causes and consequences of postural control and balance in adults with CP, as well as potential therapeutic strategies to improve any deficits. However, at this point, it does appear that these issues are prevalent and important enough to receive early and ongoing attention in the clinical setting.
The symptoms that were reported less frequently by this sample—numbness, shortness of breath, memory loss, and vision loss—have not been widely investigated in adults with CP. Nevertheless, these symptoms were endorsed by between one-fifth and one-third of participants, suggesting that they are experienced by a not-insignificant proportion of this patient population. Where prevalence estimates are available—specifically in the domains of memory [34
] and visual [27
] impairments—the current findings are generally consistent with previously observed rates. Moreover, much like the more prevalent symptoms that were assessed in this study, these less common symptoms were reported to have either stayed the same or worsened over time. The refractory nature of these symptoms may simply reflect the functional deficits that are characteristic of CP; however, it may also be the result of clinical inattention and/or ineffective treatment. Since memory and visual impairments demonstrated the closest associations to the functioning measures, it will be important for future research to further elucidate the prevalence, consequences, and most effective treatments for these symptoms, even if they do occur less frequently than other symptoms.
It was somewhat surprising that the individual symptom severity ratings were not more closely related to the four indices of psychosocial functioning. In fact, as a group, these variables only accounted for a significant amount of variance in the Social Integration scale of the CIQ, with memory loss being the only independent contributor in the prediction model. Even at the univariate level, the only significant associations were between social integration and vision loss, memory loss, and weakness and between psychological functioning and vision loss. It is difficult to contextualize these findings, given the relatively thin literature on the correlates of community integration and psychological functioning in adults with CP. A similar study by Jensen et al. in individuals with SCI also found that social integration was significantly associated with a group of seven symptoms (pain, fatigue, numbness, weakness, shortness of breath, vision loss, and memory loss) [42
]. However, in that study, memory loss, weakness, pain, and vision loss were all unique predictors [42
]. In addition, the group of symptoms was also significantly associated with psychological functioning in persons with SCI [42
]. Although strong conclusions related to the current study are premature at this point for adults with CP, other symptoms that were not assessed in this study may be more important determinants of community integration and psychological functioning. In particular, psychological symptoms, which were not targeted in this study, may be particularly important in this context. For example, previous research has found symptoms of depression and anxiety to be associated with functioning in other patient populations, such as SCI [57
] and multiple sclerosis [59
]. Future research is needed to determine whether this is also true for adults with CP. It is also possible that we did not assess the functional domains that are particularly sensitive to the eight symptoms that were examined and/or that the instruments used to assess community integration and psychological functioning did not adequately capture these constructs in the current sample. These are empirical questions that could be investigated in future work.
Several limitations of the current study should be considered. First, the number of secondary symptoms that was assessed represents only a subset of those that are experienced by individuals with CP. Although we believe, and the current results support, that the eight symptoms that were examined are important, future research should include additional symptoms (e.g., spasms, bladder/bowel dysfunction, insomnia, and weight problems) in order to examine their frequency, course, and relationship to important functional domains. Second, and relatedly, only two domains of functioning were assessed: community integration and psychological functioning. Important domains such as physical functioning, social role functioning, and participation were not measured in this study and should be considered for future research. Third, some or all of the eight symptoms that were assessed in this study are multidimensional and contain magnitude, spatial, quality, and/or temporal components. Participants in this study rated only the magnitude of these symptoms on a 0 to 10 scale, which did not permit evaluation of the nature and effect of the other symptom dimensions. A fourth limitation concerns the cross-sectional nature of the data, which does not allow for causal interpretations about the relationships between symptoms and functioning. Nor do these data allow for investigation of actual (as opposed to perceived) symptom change over time. Such longitudinal work will, among other things, help elucidate the association between advancing age and functioning in CP. In the current sample, age was not significantly associated with ratings of current severity or course for any of the eight symptoms (data not presented). Fifth, the different data collection strategies (in-person and postal) could have elicited different responses from participants. Although this procedural variability could have influenced the results in some way, systematic differences between the data collection strategies were not evident. Sixth, data were not collected on participants’ use of lower-limb orthoses, which is likely to be relevant to some of the assessed symptoms (e.g., imbalance, weakness). Finally, characteristics of the study sample may limit the generalizability of the findings. The participants were largely white, well-educated, and living independently, and almost half had spastic-type CP. Many of the participants had also been involved in previous research by our group, which could bias the current results. Moreover, although the response rate for the current study is standard for this type of research, it nevertheless represents only a subset of the population.