Video Abstract

Video Abstract

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OBJECTIVES:

Describe development curves of motor and daily activity performance in individuals with cerebral palsy (CP).

METHODS:

Participants with CP aged 1 to 20 years at baseline (n = 421) and Gross Motor Functioning Classification System (GMFCS) levels I to V (27% of participants with intellectual disability [ID]) were longitudinally assessed up to a 13-year follow-up period. Motor and daily activity performance were assessed using the relevant subdomains of the Vineland Adaptive Behavior Scales survey. Nonlinear mixed effects analyses were used, estimating the limit (average maximal performance level) and the age by which individuals reached 90% of the limit (age90).

RESULTS:

Limits of motor performance decreased with each lower functional level. Age90 for motor performance was reached at ∼6 to 8 years of age in children with GMFCS levels I to III, and at younger ages in those with lower functional levels. Limits of daily activity performance did not differ between individuals without ID with GMFCS levels I to III. The age90s of daily activities were reached between 11 and 14 (personal), 26 and 32 (domestic), and 22 and 26 years of age (community). Individuals with ID reached lower daily activity performance limits earlier.

CONCLUSIONS:

Individuals with CP continue to develop motor performance after gross motor capacity limits are reached. For those without ID, daily activities continue to develop into their 20s. Individuals who are severely affected functionally have the least favorable development of motor performance, and those with ID have the least favorable development of daily activity performance.

What’s Known on This Subject:

Although the development of motor capacity in individuals with cerebral palsy (CP) is well studied, usual performance is not. Children with CP experience limitations in performance of motor and daily activity, whereas their development into adolescence and adulthood remains unclear.

What This Study Adds:

Children with CP approach their limit of motor performance development later than motor capacity, and development of daily activities continues into adolescence (self-care activities) and adulthood (domestic and community activities). Development seems delayed compared to individuals who are typically developing.

Cerebral palsy (CP) is a common cause of childhood-onset disability and involves disorders of movement and posture attributed to nonprogressive disturbances of the developing fetal or infant brain, causing activity limitation throughout the life span.1 In the International Classification of Functioning and Health, activity is defined as “the execution of a task or action,” which can be qualified by capacity (what one can do in a standard environment) or performance (what one actually does in their usual environment).2 Activity covers activities related to motor functioning (eg, mobility) and daily life situations (eg, activities in self-care, domestic life, and community life). Children with CP can be limited in activities in these domains; moreover, these limitations are greater for those with lower levels of gross motor function (classified by the Gross Motor Function Classification System [GMFCS]) or manual ability (classified by the Manual Ability Classification System [MACS]).3,6 

Apart from the degree of activity limitation, it is also important to describe its development for individuals with CP. Knowledge on long-term development can inform treatment decisions related to health development and also guide the expectations of (younger) individuals with CP and their parents regarding their future functioning.7 The development curves of gross motor capacity, as measured with the Gross Motor Function Measure, are widely used and have lower limits for each lower level of the GMFCS. These curves have been validated for Dutch individuals with CP in the Pediatric Rehabilitation Research in the Netherlands (PERRIN) study.8,9 Recently, development curves of fine motor capacity (as measured by using the Assisting Hand Assessment) were estimated for MACS levels I to III and revealed development curves similar to those of gross motor capacity.10 However, for gross and fine motor performance, similar developmental data are not yet available. Although motor capacity and performance are related,11,13 motor capacity development does not necessarily translate to identical motor performance development, indicating that the motor capacity curves do not provide information on performance.8,14 The concept of performance is of additional interest because it concerns activities in a person’s usual environment, referring to what individuals actually do in their daily life.

Previously, the PERRIN study provided longitudinal trajectories of overall motor performance (up to age 16 years) and daily activity performance (up to age 24 years) measured by using the Vineland Adaptive Behavior Scales (VABS). For individuals with mild physical impairment, the development of motor and daily activity performance revealed, on average, an incline up to values close to those of children who are typically developing. For children with GMFCS levels IV and V, motor performance limits were significantly lower, and for those with intellectual disability (ID), development of daily activity performance was less favorable.15 Small numbers of observations at the end of the age range caused uncertainty about the limits of performance, and it was unknown whether development of performance had been completed by age 24 years.15 In line with the emerging life course perspective of health development,7,16 the development of performance further into adulthood should be considered.

Current knowledge on the development of motor and daily activity performance can be extended in several ways. First, the use of a method of analysis similar to that used in the creation of the gross motor capacity curves would provide more detailed information on the rate and average maximal performance level (limit) of development of motor and daily activity performance and allow for a comparison between motor capacity and performance curves.9 Second, adding a 13-year follow-up measurement to the PERRIN study would enable a more accurate estimation of the limits of performance and would aid in determining if development of daily activity performance continues after age 24 years. Finally, discerning between specific domains of daily activities would be relevant because development in different life areas occurs at different ages; development of self-care is expected to peak earlier than that of domestic or community activities.17 In addition, the level of functional ability and ID may influence the performance development of these activities differently. Therefore, in the current study, we aim to describe the development curves of gross and fine motor performance as well as the performance of self-care, domestic, and community activities of individuals with CP from childhood into adulthood on the basis of the level of functional ability.

Participants of the PERRIN cohort study were longitudinally measured over 3 or 4 years between 2000 and 2007. The PERRIN study consisted of 421 participants in 4 age cohorts: PERRIN 0 to 5 (baseline age: 1–2 years; 4 annual measurements; n = 97), PERRIN 5 to 9 (baseline age: 5 and 7 years; 3 annual measurements; n = 116), PERRIN 9 to 16 (baseline age: 9, 11, and 13 years; 4 annual measurements; n = 107), and PERRIN 16 to 24 (baseline age: 16–20 years; 3 biennial measurements; n = 101; see Table 1). The recruitment process of the 4 age cohorts is published elsewhere.11,13,18 Eligible participants had a clinical diagnosis of CP, and they (or a proxy) had sufficient knowledge of the Dutch language to complete interviews. Participants or their caregivers gave informed consent. In the PERRIN 16 to 24 cohort, individuals with ID (IQ of ∼<70) were excluded.18 A 13-year follow-up was performed in the PERRIN 9 to 16 and 16 to 24 cohorts (n = 121), indicated as the PERRIN DECADE study. Figure 1 is a flowchart of the inclusion of observations in the data analysis. The number of observations by cohort for all assessments is shown in Supplemental Fig 3. Approval was obtained from the medical ethics committees of the participating centers.

TABLE 1

Characteristics of the Study Population at Baseline and for Subgroups at 13-Years Follow-up

PERRIN 0–5 (n = 97; Observations: 314)PERRIN 5–9 (n = 116; Observations: 328)PERRIN 9–16PERRIN 16–24
(n = 107; Observations: 399)13-y Follow-up (n = 67a)(n = 101; Observations: 260)13-y Follow-up (n = 54a)
Age, mean (SD) 1 y 7 mo (0 y 2 mo) 6 y 3 mo (1 y 0 mo) 11 y 2 mo (1 y 8 mo) 24 y 7 mo (1 y 7 mo) 18 y 6 mo (1 y 6 mo) 31 y 8 mo (1 y 5 mo) 
Sex, n (%)       
 Male 56 (58) 76 (65) 67 (63) 45 (67) 60 (59) 29 (54) 
 Female 41 (42) 40 (35) 40 (37) 22 (33) 41 (41) 25 (46) 
Subtype, n (%)       
 Spastic 94 (97) 98 (84) 86 (80) 52 (77) 88 (88) 26 (85) 
  Unilateral 41 (42) 42 (36) 37 (35) 21 (31) 41 (41) 21 (39) 
  Bilateral 53 (55) 56 (48) 49 (46) 31 (46) 47 (47) 25 (46) 
 Dyskinetic 2 (2) 14 (12) 4 (4) 3 (5) 4 (4) 1 (2) 
 Ataxic 0 (0) 4 (4) 4 (4) 3 (5) 2 (2) 1 (2) 
 Mixed 1 (1) 0 (0) 14 (12) 9 (13) 7 (7) 6 (11) 
Level of gross motor function, n (%)       
 GMFCS level I 30 (31) 56 (48) 49 (46) 30 (45) 74 (73) 38 (70) 
 GMFCS level II 13 (13) 20 (17) 14 (13) 7 (10) 8 (8) 4 (7) 
 GMFCS level III 23 (24) 17 (15) 13 (12) 8 (12) 6 (6) 4 (7) 
 GMFCS level IV 21 (22) 9 (8) 13 (12) 9 (13) 12 (12) 7 (13) 
 GMFCS level V 10 (10) 14 (12) 18 (17) 13 (19) 1 (1) 1 (2) 
Level of manual ability, n (%)       
 MACS level I 24 (25) 44 (38) 39 (41) 26 (39) 69 (78) 41 (76) 
 MACS level II 39 (40) 38 (33) 33 (34) 22 (33) 15 (17) 10 (19) 
 MACS level III 15 (16) 15 (13) 9 (9) 7 (10) 2 (2) 1 (2) 
 MACS level IV 6 (6) 8 (7) 10 (10) 7 (10) 1 (1) 1 (2) 
 MACS level V 8 (8) 11 (10) 5 (5) 5 (7) 1 (1) 1 (2) 
 Unknown  11  13  
ID, n (%)       
 No 50 (52) 79 (68) 75 (70) 46 (69) 101 (100) 54 (100) 
 Yes 45 (46) 35 (30) 32 (30) 21 (31) 0 (0) 0 (0) 
 Unknown — — — — 
PERRIN 0–5 (n = 97; Observations: 314)PERRIN 5–9 (n = 116; Observations: 328)PERRIN 9–16PERRIN 16–24
(n = 107; Observations: 399)13-y Follow-up (n = 67a)(n = 101; Observations: 260)13-y Follow-up (n = 54a)
Age, mean (SD) 1 y 7 mo (0 y 2 mo) 6 y 3 mo (1 y 0 mo) 11 y 2 mo (1 y 8 mo) 24 y 7 mo (1 y 7 mo) 18 y 6 mo (1 y 6 mo) 31 y 8 mo (1 y 5 mo) 
Sex, n (%)       
 Male 56 (58) 76 (65) 67 (63) 45 (67) 60 (59) 29 (54) 
 Female 41 (42) 40 (35) 40 (37) 22 (33) 41 (41) 25 (46) 
Subtype, n (%)       
 Spastic 94 (97) 98 (84) 86 (80) 52 (77) 88 (88) 26 (85) 
  Unilateral 41 (42) 42 (36) 37 (35) 21 (31) 41 (41) 21 (39) 
  Bilateral 53 (55) 56 (48) 49 (46) 31 (46) 47 (47) 25 (46) 
 Dyskinetic 2 (2) 14 (12) 4 (4) 3 (5) 4 (4) 1 (2) 
 Ataxic 0 (0) 4 (4) 4 (4) 3 (5) 2 (2) 1 (2) 
 Mixed 1 (1) 0 (0) 14 (12) 9 (13) 7 (7) 6 (11) 
Level of gross motor function, n (%)       
 GMFCS level I 30 (31) 56 (48) 49 (46) 30 (45) 74 (73) 38 (70) 
 GMFCS level II 13 (13) 20 (17) 14 (13) 7 (10) 8 (8) 4 (7) 
 GMFCS level III 23 (24) 17 (15) 13 (12) 8 (12) 6 (6) 4 (7) 
 GMFCS level IV 21 (22) 9 (8) 13 (12) 9 (13) 12 (12) 7 (13) 
 GMFCS level V 10 (10) 14 (12) 18 (17) 13 (19) 1 (1) 1 (2) 
Level of manual ability, n (%)       
 MACS level I 24 (25) 44 (38) 39 (41) 26 (39) 69 (78) 41 (76) 
 MACS level II 39 (40) 38 (33) 33 (34) 22 (33) 15 (17) 10 (19) 
 MACS level III 15 (16) 15 (13) 9 (9) 7 (10) 2 (2) 1 (2) 
 MACS level IV 6 (6) 8 (7) 10 (10) 7 (10) 1 (1) 1 (2) 
 MACS level V 8 (8) 11 (10) 5 (5) 5 (7) 1 (1) 1 (2) 
 Unknown  11  13  
ID, n (%)       
 No 50 (52) 79 (68) 75 (70) 46 (69) 101 (100) 54 (100) 
 Yes 45 (46) 35 (30) 32 (30) 21 (31) 0 (0) 0 (0) 
 Unknown — — — — 

—, not applicable.

a

Thirteen-year follow-up: n = 121.

FIGURE 1

Flow diagram of the inclusion of participants and observations.

FIGURE 1

Flow diagram of the inclusion of participants and observations.

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Motor and Daily Activity Performance

Gross and fine motor performance and performance of personal, domestic, and community daily activities were measured by using the Dutch version of the VABS survey motor and daily living skills subdomains.17,19 The VABS survey is used to assess performance by means of a semistructured interview. The original version was found reliable and valid for individuals up to age 19 years who were typically developing and adults with ID; the Dutch version was validated for individuals with ID.17,20 Items addressed activities of daily life in gross (20 items) and fine motor performance (16 items) and personal (39 items; eg, getting dressed or doing one’s hair), domestic (21 items; eg, doing laundry or cooking), and community daily activities (32 items; eg, using a bank account or job skills). These activities were scored as never performed (0), sometimes or partially performed (1), or usually or habitually performed (2). A validated Dutch version of the screener of the VABS survey was used for the PERRIN 0 to 5 cohort.21 This screener contains less items for each subdomain and is age appropriate for children age 0 to 12 years. Because there were few items for domestic and community daily activities, those scores of the PERRIN 0 to 5 cohort were discarded. Other VABS survey screener scores were linearly transformed to match the VABS survey scores. Gross and fine motor performances were not assessed in the PERRIN 16 to 24 cohort because that study was focused on daily activities and participation.18 Consequently, gross and fine motor performances were described over an age range of 1 to 27 years, and daily activity performance (individuals without ID) was described over age ranges of 1 to 34 years (personal) and 5 to 34 years (domestic and community activities). Finally, because of the exclusion of individuals with ID in the PERRIN 16 to 24 cohort, daily activity performance for this subgroup was described for ages up to 27 years.

Characteristics of CP

The level of functional ability registered at baseline was described for gross motor functioning (GMFCS) and manual ability (MACS).5,6 The GMFCS and MACS are classification systems based on functional abilities with levels that range from I (highest level) to V (lowest level). GMFCS levels range from walking without limitation (level I) to being severely limited in self-mobility and posture control (level V); individuals with a GMFCS level of IV or V are unable to walk independently. MACS levels range from handling objects in everyday life easily (level I) to needing assistance in handling all objects or with simple actions (level V). Individuals were classified with ID if they had an IQ <70, which was assessed by the Snijders-Oomen Nonverbal Intelligence Test (PERRIN 0–5 cohort)22 or the Raven’s Colored Progressive Matrices (PERRIN 5–9 cohort),23 or on the basis of school type; those following a special education program for children with ID were classified as individuals with ID (PERRIN 9–16 cohort).13 

To describe baseline characteristics, frequencies of sex, subtype of CP, GMFCS level, MACS level, and ID were calculated. To estimate the motor and daily activity performance development, similar to the gross motor capacity curves,8,9 nonlinear mixed effects modeling was conducted on the 5 VABS subdomain scores for each GMFCS or MACS level separately for age (continuous variable) by using R 3.2.5.24 Gross motor performance was analyzed by GMFCS level, and fine motor performance was analyzed by MACS level. To allow for comparison and ease of interpretation between the 3 domains of daily activity performance, the 3 domains were all analyzed by GMFCS level. In accordance with a previous PERRIN publication,15 daily activity performance was analyzed separately for individuals with and without ID. The nonlinear model has 2 parameters with straightforward clinical interpretations: the rate (speed of development) and limit (average maximal performance level for a subgroup). In the used model, a limit of maximal potential performance and a development that is rapid at first but levels off toward reaching this limit are assumed. These assumptions seem to fit the motor and daily activity performance development described by the reference values of the VABS survey.17 To enhance interpretation, the rate parameters were used to calculate the average age by which individuals reached 90% of the limit (age90). Higher values of age90 therefore indicate slower development toward the limit. The 95% confidence intervals (CIs) of the limit and age90 were calculated and used to detect differences between GMFCS or MACS levels, with significant differences if the 95% CIs did not overlap (P < .05). The degree of interindividual variability of the limit was estimated by including a random limit in the model. From the random variance around limits, we calculated 50% ranges that encompassed the estimated limits of 50% of the individuals in the analysis. Because development of the subdomains of motor and activity performance does not necessarily start at birth, a start age of modeled development was selected on the basis of the best fit of all observations, irrespective of GMFCS or MACS level (according to the Akaike information criterion). The residual SDs of the models provide an indication of the model fit.

To allow for the low number of observations in certain subgroups according to functional level and ID, no daily activity performance curves were estimated for individuals without ID with a GMFCS level of V, and the observations of individuals with ID were combined for the daily activity performance curves of GMFCS levels I to III and GMFCS levels IV and V.

Overall, 421 participants (50% with a GMFCS level of I, 45% with an MACS level of I, and 73% without ID) contributed to 1428 VABS survey observations at ages 1 to 34 years. Table 1 includes the characteristics of the participants of the 4 age cohorts at baseline and of the 2 oldest cohorts at the 13-year follow-up. Dropouts are described in Fig 1 and were not selective regarding sex or CP characteristics. The estimated average development curves by GMFCS or MACS level are shown in Fig 2. Parameter estimates (limit and age90) and 50% ranges of the limits are reported in Table 2. The raw observations are shown in Supplemental Figs 4–8 with the estimated curves and 50% ranges of the limits for the motor and daily activity subdomains.

FIGURE 2

Average curves of motor and daily activity performance development, with the age equivalents of the reference group indicated in gray. DLS, daily living skills.

FIGURE 2

Average curves of motor and daily activity performance development, with the age equivalents of the reference group indicated in gray. DLS, daily living skills.

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TABLE 2

Model Parameters of Gross and Fine Motor Performance Development (Age 1–27 Years) for GMFCS and MACS Levels and Parameters of Performance of Daily Living Skills Development (Age 1–34 Years) for GMFCS Level and Intellectual Status

NNo. Observations, MeanLimit(95% CI)50% RangeAge90(95% CI)Residual SDsOffset
Gross motor performance          
  GMFCS level          
  I 134 3.4 37.8 (36.9–38.7) 35.8–39.8 6 y 8 mo (6 y 1 mo–7 y 3 mo) 3.0 0.0 
  II 44 3.3 31.2 (28.9–33.6) 28.5–33.9 8 y 1 mo (6 y 6 mo–10 y 0 mo) 3.3 0.0 
  III 53 3.2 22.2 (19.7–24.6) 18.9–25.4 6 y 8 mo (5 y 0 mo–9 y 0 mo) 3.6 0.0 
  IV 43 3.2 10.1 (8.8–11.4) 7.6–12.6 2 y 4 mo (1 y 3 mo–4 y 3 mo) 2.2 0.0 
  V 40 3.7 3.9 (3.3–4.4) 2.8–4.9 1 y 3 mo (0 y 2 mo–9 y 7 mo) 1.5 0.0 
Fine motor performance          
  MACS level          
  I 106 3.5 30.9 (29.7–32.2) 27.9–32.0 7 y 2 mo (6 y 6 mo–7 y 11 mo) 2.2 1.2 
  II 109 3.3 27.3 (25.6–29.0) 23.2–31.5 7 y 1 mo (6 y 3 mo–8 y 0 mo) 2.5 1.2 
  III 39 3.4 20.4 (17.0–23.8) 15.0–25.8 6 y 7 mo (4 y 9 mo–9 y 3 mo) 2.7 1.2 
  IV 24 3.3 7.6 (5.5–9.8) 4.7–10.5 2 y 11 mo (1 y 5 mo–15 y 5 mo) 4.1 1.2 
  V 23 3.4 1.0 (0.4–1.5) 0.2–1.7 1 y 6 mo (1 y 3 mo–4 y 4 mo) 1.0 1.2 
Personal activity performance          
 GMFCS level          
  No ID          
   I 194 3.3 77.8 (76.8–78.7) 75.2–78.0 11 y 2 mo (10 y 9 mo–11 y 7 mo) 3.9 0.4 
   II 42 3.2 74.7 (70.0–79.4) 68.5–78.0 12 y 5 mo (10 y 11 mo–14 y 2 mo) 4.0 0.4 
   III 36 3.3 73.1 (67.1–79.1) 66.0–78.0 13 y 8 mo (11 y 10 mo–15 y 9 mo) 4.4 0.4 
   IV 27 3.0 68.3 (61.7–74.8) 61.5–75.1 15 y 2 mo (12 y 3 mo–18 y 9 mo) 6.0 0.4 
  ID          
   I–III 44 3.0 53.6 (45.7–61.5) 45.6–61.6 11 y 2 mo (8 y 6 mo–14 y 8 mo) 5.8 0.4 
   IV–V 63 3.3 19.0 (15.7–22.3) 10.9–27.1 3 y 0 mo (2 y 4 mo–4 y 5 mo) 6.8 1.6a 
Domestic activity performance          
 GMFCS level          
  No ID          
   I 168 3.3 39.9 (37.6–42.3) 36.1–42.0 27 y 5 mo (24 y 11 mo–30 y 2 mo) 4.4 3.4 
   II 34 3.3 35.2 (30.4–39.9) 32.6–37.8 26 y 8 mo (21 y 10 mo–32 y 9 mo) 3.9 3.4 
   III 26 3.4 34.0 (24.0–43.9) 28.6–39.3 32 y 5 mo (22 y 6 mo–47 y 8 mo) 5.0 4.4a 
   IV 21 3.0 16.9 (12.6–21.3) 12.1–21.7 12 y 9 mo (7 y 5 mo–25 y 0 mo) 5.1 3.4 
  ID          
   I–III 27 2.9 10.3 (7.9–12.8) 8.2–12.5 8 y 5 mo (5 y 7 mo–14 y 10 mo) 3.5 3.4 
   IV–V 40 3.7 2.9 (1.7–4.2) 0.6–5.3 6 y 6 mo (4 y 9 mo–72 y 2 mo) 3.5 4.7a 
Community activity performance          
 GMFCS level          
  No ID          
   I 168 3.4 64.4 (62.5–66.4) 60.8–64.0 23 y 4 mo (22 y 2 mo–24 y 7 mo) 4.4 3.0 
   II 34 3.3 64.0 (58.6–69.5) 60.8–64.0 26 y 5 mo (23 y 3 mo–30 y 1 mo) 4.3 3.0 
   III 26 3.5 54.1 (45.9–62.3) 46.6–61.6 22 y 11 mo (18 y 10 mo–28 y 1 mo) 5.1 3.0 
   IV 22 3.3 53.3 (45.6–61.0) 46.8–59.9 23 y 10 mo (18 y 9 mo–30 y 5 mo) 6.0 3.0 
  ID          
   I–III 27 2.9 21.8 (15.3–28.3) 15.1–28.5 14 y 3 mo (9 y 10 mo–21 y 7 mo) 5.1 3.0 
   IV–V 40 3.7 6.6 (3.9–9.4) 1.3–11.9 6 y 6 mo (4 y 10 mo–90 y 8 mo) 4.3 4.8a 
NNo. Observations, MeanLimit(95% CI)50% RangeAge90(95% CI)Residual SDsOffset
Gross motor performance          
  GMFCS level          
  I 134 3.4 37.8 (36.9–38.7) 35.8–39.8 6 y 8 mo (6 y 1 mo–7 y 3 mo) 3.0 0.0 
  II 44 3.3 31.2 (28.9–33.6) 28.5–33.9 8 y 1 mo (6 y 6 mo–10 y 0 mo) 3.3 0.0 
  III 53 3.2 22.2 (19.7–24.6) 18.9–25.4 6 y 8 mo (5 y 0 mo–9 y 0 mo) 3.6 0.0 
  IV 43 3.2 10.1 (8.8–11.4) 7.6–12.6 2 y 4 mo (1 y 3 mo–4 y 3 mo) 2.2 0.0 
  V 40 3.7 3.9 (3.3–4.4) 2.8–4.9 1 y 3 mo (0 y 2 mo–9 y 7 mo) 1.5 0.0 
Fine motor performance          
  MACS level          
  I 106 3.5 30.9 (29.7–32.2) 27.9–32.0 7 y 2 mo (6 y 6 mo–7 y 11 mo) 2.2 1.2 
  II 109 3.3 27.3 (25.6–29.0) 23.2–31.5 7 y 1 mo (6 y 3 mo–8 y 0 mo) 2.5 1.2 
  III 39 3.4 20.4 (17.0–23.8) 15.0–25.8 6 y 7 mo (4 y 9 mo–9 y 3 mo) 2.7 1.2 
  IV 24 3.3 7.6 (5.5–9.8) 4.7–10.5 2 y 11 mo (1 y 5 mo–15 y 5 mo) 4.1 1.2 
  V 23 3.4 1.0 (0.4–1.5) 0.2–1.7 1 y 6 mo (1 y 3 mo–4 y 4 mo) 1.0 1.2 
Personal activity performance          
 GMFCS level          
  No ID          
   I 194 3.3 77.8 (76.8–78.7) 75.2–78.0 11 y 2 mo (10 y 9 mo–11 y 7 mo) 3.9 0.4 
   II 42 3.2 74.7 (70.0–79.4) 68.5–78.0 12 y 5 mo (10 y 11 mo–14 y 2 mo) 4.0 0.4 
   III 36 3.3 73.1 (67.1–79.1) 66.0–78.0 13 y 8 mo (11 y 10 mo–15 y 9 mo) 4.4 0.4 
   IV 27 3.0 68.3 (61.7–74.8) 61.5–75.1 15 y 2 mo (12 y 3 mo–18 y 9 mo) 6.0 0.4 
  ID          
   I–III 44 3.0 53.6 (45.7–61.5) 45.6–61.6 11 y 2 mo (8 y 6 mo–14 y 8 mo) 5.8 0.4 
   IV–V 63 3.3 19.0 (15.7–22.3) 10.9–27.1 3 y 0 mo (2 y 4 mo–4 y 5 mo) 6.8 1.6a 
Domestic activity performance          
 GMFCS level          
  No ID          
   I 168 3.3 39.9 (37.6–42.3) 36.1–42.0 27 y 5 mo (24 y 11 mo–30 y 2 mo) 4.4 3.4 
   II 34 3.3 35.2 (30.4–39.9) 32.6–37.8 26 y 8 mo (21 y 10 mo–32 y 9 mo) 3.9 3.4 
   III 26 3.4 34.0 (24.0–43.9) 28.6–39.3 32 y 5 mo (22 y 6 mo–47 y 8 mo) 5.0 4.4a 
   IV 21 3.0 16.9 (12.6–21.3) 12.1–21.7 12 y 9 mo (7 y 5 mo–25 y 0 mo) 5.1 3.4 
  ID          
   I–III 27 2.9 10.3 (7.9–12.8) 8.2–12.5 8 y 5 mo (5 y 7 mo–14 y 10 mo) 3.5 3.4 
   IV–V 40 3.7 2.9 (1.7–4.2) 0.6–5.3 6 y 6 mo (4 y 9 mo–72 y 2 mo) 3.5 4.7a 
Community activity performance          
 GMFCS level          
  No ID          
   I 168 3.4 64.4 (62.5–66.4) 60.8–64.0 23 y 4 mo (22 y 2 mo–24 y 7 mo) 4.4 3.0 
   II 34 3.3 64.0 (58.6–69.5) 60.8–64.0 26 y 5 mo (23 y 3 mo–30 y 1 mo) 4.3 3.0 
   III 26 3.5 54.1 (45.9–62.3) 46.6–61.6 22 y 11 mo (18 y 10 mo–28 y 1 mo) 5.1 3.0 
   IV 22 3.3 53.3 (45.6–61.0) 46.8–59.9 23 y 10 mo (18 y 9 mo–30 y 5 mo) 6.0 3.0 
  ID          
   I–III 27 2.9 21.8 (15.3–28.3) 15.1–28.5 14 y 3 mo (9 y 10 mo–21 y 7 mo) 5.1 3.0 
   IV–V 40 3.7 6.6 (3.9–9.4) 1.3–11.9 6 y 6 mo (4 y 10 mo–90 y 8 mo) 4.3 4.8a 
a

If the offset (determined on the basis of all observations of a subdomain) resulted in a severity subgroup model that did not fit, then the offset was based on the optimal fit to the observations of the subgroup.

The estimated limits of gross and fine motor performance revealed a significant difference between all GMFCS and MACS levels because the 95% CIs did not overlap. Limits were lower for each lower level of gross motor function or manual ability (Table 2).

The age90s revealed no significant difference between GMFCS and MACS levels I to III and were estimated at ages 6 to 8 years (Table 2). Individuals with GMFCS and MACS levels of IV and V had a lower age90 compared with those with levels I to III, indicating that they reach their lower limit at a younger age compared with their peers who are less affected. Furthermore, both the large 95% CIs around the age90 and the raw observations of individuals with an MACS level of IV and a GMFCS level of V suggested that average development did not increase or decrease over time (Supplemental Fig 4).

The limits of personal and domestic daily activity performance revealed no significant difference between individuals with GMFCS levels of I to III (without ID), whereas the limits for those with a GMFCS level of IV were lower compared with the limits for those with a GMFCS level of I (II and III for domestic activity performance). The community daily activity limits of individuals with GMFCS levels of III and IV were lower than that of those with a GMFCS level of I. Interindividual variance of daily activity performance limits (indicated by the 50% ranges) tended to increase with increasing GMFCS level (Table 2).

The age90s of individuals without ID (GMFCS levels I–IV) revealed no significant difference between GMFCS levels except for individuals with a GMFCS level of IV, who had a lower age90 for the community domain. The age90 ranged from 11 to 15 years old for personal daily activities, from 26 to 32 years old for domestic daily activities, and from 22 to 26 years old for community daily activities.

In all domains of daily activity, the limits of individuals with ID were significantly lower than the limits of individuals without ID. Among individuals with ID, the limits of those with GMFCS levels of IV and V were lower than the limits of those with GMFCS levels of I to III (Table 2).

Individuals with ID reached their limits earlier than individuals without ID, as was indicated by lower age90s. This was significantly so for personal activities of individuals with ID and GMFCS levels of IV and V and for domestic and community activities of individuals with ID and GMFCS levels of I to III. Furthermore, for domestic and community activities, both the large 95% CIs around the age90s and the raw observations of individuals with ID and GMFCS levels IV and V suggested that average development did not increase or decrease over time (Supplemental Fig 4).

In this study, we describe the development curves of motor and daily activity performance from childhood into adulthood of individuals with CP by their functional ability level to supplement the widely used development curves of motor capacity of children with CP.8 Individuals with CP with walking ability (GMFCS levels of I–III) approached their maximal performance levels at age 6 to 8 years for gross and fine motor performance, age 11 to 14 years for personal (self-care) activities, age 26 to 32 years for domestic activities, and age 22 to 26 years for community daily activities. Individuals who were severely affected showed the least favorable development of motor performance and daily activities, which was observed as lower maximal performance levels in all domains approached at a younger age.

The average maximal gross motor performance levels (limits) of children with CP were distinctly lower with each lower GMFCS level. Although we observed a pattern for motor performance that is comparable to the published gross motor capacity curves, children with CP continue to improve their gross motor performance level as they age (age90 for GMFCS levels I–III at 6–8 years old), whereas their gross motor capacity has plateaud at a younger age (age90 at 4–5 years old).9 A similar effect of functional classification on the limits and a similar slower development are observed when comparing the fine motor performance curves with those of fine motor capacity in a Swedish cohort.10 However, direct comparison between these curves of performance and capacity requires caution because the specific activities assessed in the outcome measures (Gross Motor Function Measure or Assisting Hand Assessment for capacity and VABS survey for performance) are not identical.17,25 Nevertheless, a lagged development of motor performance seems valid because performance does not only depend on the ability of the person to do activities in a standardized setting (ie, capacity) but also is affected by personal factors (such as motivation or self-efficacy) and the environment in which the activities are performed in daily life.8,12,14 Therefore, health care professionals should be aware of further development of motor performance in children with CP after they have reached their limit in motor capacity.

Development of self-care activities continued into adolescence, whereas domestic and community activities continued to develop into the early- and late-20s. For these specific domains of activities, the estimated maximal levels of performance of individuals without ID with GMFCS levels of I to III are close to those of individuals who are typically developing,17 which is similar to our previous report on the overall daily activities domain.15 Our results further reveal that development also occurs differently in specific domains of activities for individuals with CP. Regarding the pace of development, reference values of the VABS survey reveal that individuals who are typically developing reach 90% of their maximal performance level of self-care, domestic, and community activity at about 7, 18, and 15 years of age, respectively.17 This indicates that even though the limits are similar, the development of daily activity performance in individuals with CP without ID seems to be delayed, which is most pronounced in domestic activities.17 

The ages up to which individuals with CP without ID were found to develop daily activities are surprisingly high. The ongoing development of daily activities well into adulthood supports the need for taking a life course health development approach for individuals with CP.7,16 In addition to the lagged development of daily activity performance presented here, high proportions of this sample of individuals with CP experience difficulty in participation in domestic and community life in young adulthood.26 Moreover, European adolescents with CP participate less frequently in domestic activities (doing chores) and community life (having work experience).27 These aspects of difficulty and frequency of performance are also important to consider in clinical decision-making. Routine monitoring of individuals with CP for activity limitations or participation restrictions is recommended into adulthood because development of the performance of daily activities does not stop at age 18 (when many individuals leave the pediatric setting and make the transfer to adult health care services).

The less favorable development of performance in those individuals with CP with significant impairments and in individuals with CP and ID support findings of previous cross-sectional studies of younger populations.4,13,15,28 This knowledge can be used to educate and counsel these individuals and their families on expected future daily activity performance. In addition, clinicians should take the development curves into consideration when setting treatment goals (eg, focusing treatment on increasing their independence in daily activities or promoting participation by creating opportunities while also offering adequate supports and resources).

To further specify expectations of performance development and to identify subgroups at an increased risk of a less favorable development of activity performance, future studies should be used to determine which personal factors besides CP-related factors, such as GMFCS level, MACS level, and ID, and which environmental factors are determinants of performance development. In addition, it is of interest to examine which interventions and at what point during the development curve can best facilitate performance. For instance, we could evaluate the effects of a boost of therapy with high intensity at an age when change in performance is expected or the effects of offering participation-based therapy29 when the development of activities stabilizes.

A general limitation relates to the relatively small subgroups of those other than the GMFCS level I without ID; there were in particular small numbers of observations for individuals with GMFCS levels of II to IV in the age of mid-20s and up. Second, comparison with the VABS survey reference values is hampered by a different culture (United States) and time frame (1984).17 Furthermore, both caregiver- (for children and adults with ID) and self-reported scores (for adolescents and adults without ID) were used. However, we assume that the effect on the results will be limited because of the straightforward content of the VABS survey items.

The development of motor performance in individuals with CP continues after gross motor capacity limits have been reached in childhood. Self-care performance continues into adolescence, and the development of domestic and community activities progresses into the mid- to late-20s. Individuals with severe CP show the least favorable development of motor and daily activity performance.

     
  • age90

    age by which individuals reached 90% of the limit

  •  
  • CI

    confidence interval

  •  
  • CP

    cerebral palsy

  •  
  • GMFCS

    Gross Motor Function Classification System

  •  
  • ID

    intellectual disability

  •  
  • MACS

    Manual Ability Classification System

  •  
  • PERRIN

    Pediatric Rehabilitation Research in the Netherlands

  •  
  • VABS

    Vineland Adaptive Behavior Scales

Ms van Gorp collected the data of the 13-year follow-up, conducted the analysis, and drafted and revised the manuscript; Dr Roebroeck conceptualized, designed, and guided the study, interpreted the results of the analysis, and critically reviewed the content of the manuscript; Dr Swan Tan prepared the database for analysis and critically reviewed the content of the manuscript; Dr de Groot interpreted the results of the analysis and critically reviewed the content of the manuscript; Dr Gorter interpreted the results for clinical relevance and critically reviewed the content of the manuscript; Dr Smits prepared the database for analysis, contributed to the analysis, and critically reviewed the content of the manuscript; Ms Schmidt prepared the database for analysis, contributed to the initial analysis, and critically reviewed the content of the manuscript; Dr Dallmeijer conceptualized, designed, and guided the study, interpreted the results of the analysis for clinical relevance, and critically reviewed the content of the manuscript; and all authors approved the final manuscript as submitted.

FUNDING: Supported by Fonds NutsOhra (grant 1403-030 to Dr Dallmeijer) and Rijndam Rehabilitation (Rotterdam, the Netherlands).

This study was performed as part of the PERRIN research program.

Members of the PERRIN-DECADE Study Group are as follows:

VU University Medical Center (Amsterdam, Netherlands): A.J. Dallmeijer, M. van Gorp, L. van Wely, V. de Groot; Erasmus MC University Medical Center and Rijndam Rehabilitation (Rotterdam, Netherlands): M.E. Roebroeck, S.S. Tan, J. van Meeteren, W. van der Slot, H. Stam; University Medical Center Utrecht and De Hoogstraat Rehabilitation Center (Utrecht, Netherlands): M. Ketelaar, J.M. Voorman; Revalidatie Friesland and University Medical Center Groningen (Groningen, Netherlands): H.A. Reinders-Messelink; McMaster University (Hamilton, Canada): J.W. Gorter; BOSK, Association of Physically Disabled Persons and their Parents: J. Verheijden.

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Competing Interests

POTENTIAL CONFLICT OF INTEREST: The authors have indicated they have no potential conflicts of interest to disclose.

FINANCIAL DISCLOSURE: The authors have indicated they have no financial relationships relevant to this article to disclose.

Supplementary data