Introduction

The concept of cerebral palsy (CP) has evolved over time [1–3]; it is currently defined as “a group of disorders of the development of movement and posture, causing activity limitation, that are attributed to non-progressive disturbances that occurred in the developing fetal or infant brain. The motor disorders of cerebral palsy are often accompanied by disturbances of sensation, cognition, communication, perception, and/or behavior, and/or by a seizure disorder” [4]. The evolution of this concept has played a critical role in changing the disability paradigm, which has developed from a “deficit theory” to a “biopsychosocial conception,” supported by cultural importance and the participation of disabled people [5]. Moreover, CP is the most common physical impairment in childhood. Its prevalence in developed countries is estimated at 2–2.5 cases per 1,000 live births [6, 7]. However, the proportion of school-aged children in the United States diagnosed with CP is 3–4 per 1,000 people. This disorder affects more than 17 million people in the world and 25 percent of the affected children will never be able to walk. Just half of those with a severe intellectual disability survive to become adults [8].

The concept of Quality of Life (QoL) is relatively new in health evaluation. It is difficult to define the concept because it is not a simple notion. Although there is as yet no consensus on defining criteria, most of the international scientific community accepts that it includes the fulfillment of eight basic needs that represent the essence in everyone’s existence: emotional, economic, and physical well-being, interpersonal relationships, personal development, self-determination, social inclusion, and rights [9]. Several studies have affirmed that some factors such as interpersonal relationships [10], sexuality [11], and physical conditions [12] are also crucial to a higher QoL.

For disabled persons, gaining self-determination is paramount as it implies a willingness to take control of one’s own opportunities, decisions, and environmental conditions [13, 14]. This is vital because it promotes individuals to be active participants in the search for solutions to their needs. However, interest in self-determination is very recent, so few established theoretical models exist. Furthermore, comprehension of the concept and the consequences of QoL are still expanding [3]. Wehmeyer is the most recognized author on this subject, and his definition is the most accepted and well-known: “Self-determination is the process by which a person’s action is the primary causal agent in one’s life and to make choices regarding one’s actions free from undue external influence or interference” [15]. Therefore, discussing self-determination refers to rights, skills, actions, ethics, responsibility, authority, and freedom. It relates to the abilities and attitudes required to act as the primary causal agent in one’s life and to achieve adequate social interdependence [16]. This concept is of particular interest if we consider that, until recently, disabled people tended to be treated as if they were passive, depending on their families, professionals, and society in general to make their life decisions [17, 18]. However, this trend is changing; it is now recognized that disabled individuals should be actively involved in obtaining all the services and materials they need [5, 19].

Despite some progress having been made, the participation of disabled people locally, regionally, or nationally in the agencies where their life decisions are made is still low; even associations for persons with disabilities generally have administrations that are led by people without those disabilities. It is unknown whether this problem exists because disabled people do not have the qualifications to fulfill these positions or because people’s expectations of disabled individuals are too low. Either way, the qualifications of disabled people are an important factor on the path to self-determination and promoting a better QoL [20, 21].

Although several studies evaluating the QoL of people with CP have been conducted focusing on young people or children [22–25], most of these subjects go on to become adults, and QoL for that population has received far less attention.

Therefore, in this study, we analyzed the QoL of adults with CP who did not have an intellectual disability to elucidate relevant sociodemographic factors and predictors.

Materials and methods

Results

Participants’ characteristics are presented in Table 1. There was a significant relationship between age and education level (p = .001).

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Table 1. Participant characteristics (N = 75).

https://doi.org/10.1371/journal.pone.0191960.t001

GENCAT QoL scale

It is important to note that the overall mean score indicator of the participants’ QoL was 103.29, which corresponds to the 56.6th percentile on the GENCAT scale (Cronbach’s alpha = 0.92). The items with the lowest mean score were “has a satisfactory sexual life” (mean = 1.87 points, SD = 1.24, range = 1–4) and “presents with depression symptoms” (mean = 1.95 points, SD = 1.08, range = 1–4). Those with higher mean scores were “has good personal hygiene” (mean = 3.89 points, SD = .39, range = 1–4) and “reports feeling loved by the most important people to him or her” (mean = 3.81 points, SD = .54, range = 1–4).

When analyzing the eight factors that compose QoL and relating them to the different sociodemographic variables we found the following results. A relationship between age and “personal development” was identified. This factor was increased in the youngest participants. It was observed that people who lived in their own residence had a higher level of self-determination than those who lived in a center or group home. However, those who lived with family or at a center obtained higher scores in the “social inclusion” factor than those who lived in their own residence. In addition, those who had their homes adapted obtained higher scores for the “physical wellbeing” factor. Participants who lived with their partner obtained a higher score in the factors “interpersonal relationships,” “personal development,” and “self-determination.” Examining the level of education, we found significant differences in the factors “personal development” and “self-determination.” Moreover, those who currently had a partner obtained higher scores in “interpersonal relationships,” “personal development,” “rights,” and the global QoL index. Finally, participants who maintained sexual relationships had higher scores in “interpersonal relationships,” “personal development,” “self-determination,” and the global QoL index (Tables 2 and 3). However, no differences were found for the “material wellbeing” or “emotional wellbeing” factors.

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Table 2. Comparing the GENCAT Quality of Life Scale (part 1)^*.

https://doi.org/10.1371/journal.pone.0191960.t002

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Table 3. Comparing the GENCAT Quality of Life Scale (part 2)^*.

https://doi.org/10.1371/journal.pone.0191960.t003

Post-hoc subgroup analyses, presented in Table 4, showed significant differences between the following groups and variables:

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Table 4. Post-hoc subgroup analyses^*.

https://doi.org/10.1371/journal.pone.0191960.t004

To study the possible relationship between sociodemographic variables and the GENCAT scale, we developed a linear model. For this, we included variables that showed p-values lower than .20 derived from the previous analysis (i.e., active sexual relationships, partnership, education, and people with whom they live) and the variables age and sex. We determined that the “maintenance of sexual relationships” was related to the GENCAT and increased QoL (Table 5).

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Table 5. Linear model.

https://doi.org/10.1371/journal.pone.0191960.t005

Discussion

The aim of this study was to analyze the QoL of adults with CP who did not have an intellectual disability and investigate possible predictors of a higher QoL.

The overall mean score indicator of participants’ QoL was 103.29, which corresponds to the 56.6th percentile on the GENCAT scale. This means adults with CP tend to perceive their QoL the same way the general population does. Consistent with this finding, Hergenröder and Blank [10] stated that subjective wellbeing and general satisfaction were not diminished in adults with CP. However, the sample population in Morgan et al. [32] reported that they perceived their health-related QoL to be poor.

We agree with Davis et al. [23], who affirmed in their study of adolescents with CP and their parents that self-determination is a crucial factor, especially when teenagers opined about their future and felt good about themselves. Similarly, Tarsuslu and Livanelioglu [12] stated that while physical aspects such as mobility and pain are stronger indicators of health-related QoL in healthy populations, for young adults with CP, psychological factors such as communication skills and social inclusion are more important. Moreover, we agree with Hergenröder and Blank [10], who stated that interpersonal relationships are critical to a higher QoL. It is also noteworthy that in Wiegerink et al.’s study [11], they found a relationship between age and time spent dating and stated that being of an older age was associated with greater sexual activity.

With respect to sociodemographic variables, we focused on middle-aged adults with CP (mean = 40.84 years). In other studies, very little information about this age range exists. Most publications were centered on children and adolescents [29, 33]. Some similar studies have addressed middle-aged adults [10, 34]; however, these were largely male-dominated, which was also the case in Young et al. [29].

Regarding place of residence, we found it striking that most participants lived in their family home; however, almost half had not had their home adapted. Comparing our results with other studies that investigated the places where adults with CP reside, Blum et al. [35] showed similar results, affirming that 90 percent lived in parental households, 7 percent lived in group situations, and only two people lived alone. However, that study addressed adolescents who are typically not independent. Andersson and Mattson [34] concluded that 84 percent lived in their own house, with or without home help service.

Regarding participants’ educational level, the data showed a declining percentage and an inverse proportional relationship with age. The percentages of our study are different from those obtained by Hergenröder and Blank [10], who concluded that 32 percent did not have professional qualifications, 44 percent did, and 24 percent were working towards higher education. In addition, in Van der Dussen et al.'s study [36], 53 percent had completed secondary education, 15 percent had not, and 12.5 percent attended a school for people with special needs. In other words, in our sample, participants had less education (5.4 percent had completed higher education, 16.2 percent had professional qualifications, 13.5 percent had completed secondary education, 23 percent had completed primary studies, and 41.9 percent had no educational record). Our relatively higher proportion rate in level 5 of the GMFCS might explain this fact.

Regarding personal relationships, consistent with other studies, 71.8 percent reported that they were not currently involved in a sexual relationship. In Van der Dussen et al. [36], 87.5 percent were single, 12.5 percent were married or living with their partner, and 5 percent had children. Wiegerink et al. [37, 38] showed that 23 percent of people in their sample were in a relationship. On the other hand, in a survey about sexuality [39], single men with CP displayed lower scores on a standardized sexuality instrument concerning sexual information, experience, attitude, psychological symptoms, affection, and satisfaction than did healthy single men. Moreover, both middle-aged men and women with CP had higher scores for psychological items; however, women reported a lower rate of sexual satisfaction [39]. Finally, it is worth highlighting the relationship found in the linear model, where the maintenance of sexual relationships was related to the GENCAT and increased their QoL. No studies were found relating these two factors, and therefore it would also be interesting to take them into account for future researches.

Conclusion

The QoL conceptual framework created by Schalock and Verdugo [28] was a useful guide for this study. The results indicate that adults with CP perceive their QoL as equivalent to that of healthy adults. “Interpersonal relationships,” “personal development,” and “social inclusion” were the most important factors for QoL, whereas “material wellbeing” and “physical wellbeing” were the least. Our data also support the theory that a high QoL is related to having a current sexual relationship. These results have social implications for nursing practice. It is important to encourage sexual education among adults with CP and adapt existing social inclusion programs to increase their QoL.

Acknowledgments

The authors would like to thank Marta Sanchez-Zaballos for dedicating her time and providing additional guidance, suggestions, and helping to edit the paper. We would also like to thank PLOS editor Karen Lidzba and the anonymous reviewers for their meticulous scrutiny.