Advertisement

Epidemiology of Cerebral Palsy in Adulthood: A Systematic Review and Meta-analysis of the Most Frequently Studied Outcomes

Published:February 11, 2020DOI:https://doi.org/10.1016/j.apmr.2020.01.009

      Highlights

      • On average, adults with cerebral palsy (CP) are fatigued, and a majority experience pain.
      • A minority of adults with CP are employed and live independently.
      • Those without intellectual disability are often ambulant and live independently.
      • Epilepsy and asthma are common comorbidities in adults with CP.

      Abstract

      Objective

      To describe the epidemiology of health status, impairments, activities and participation in adults with cerebral palsy (CP).

      Data Sources

      Embase, MEDLINE, Web of Science, PsycINFO, Cumulative Index to Nursing and Allied Health, Cochrane, and Google Scholar were searched for 3 themes (“cerebral palsy,” “adult,” and “outcome assessment”) in literature published between January 2000 and December 2018.

      Study Selection

      Full-article peer-reviewed English journal articles on descriptive, observational, or experimental studies describing the most studied outcomes in adults with CP (n≥25, age≥18y) were included. Studies were included in the analyses if frequently studied outcomes were described in at least 3 studies using similar methods of assessment.

      Data Extraction

      Data were extracted independently by 2 authors from 65 articles (total N=28,429) using a standardized score sheet.

      Data Synthesis

      Meta-analyses revealed that overall, on average 65.1% (95% confidence interval [CI], 55.1-74.5) of adults with CP experienced pain, 57.9% (95% CI, 51.1-64.6) were ambulant, 65.5% (95% CI, 61.2-69.7) had little or no limitation in manual ability, 18.2% (95% CI, 10.6-27.2) had tertiary education, 39.2% (95% CI, 31.5;47.1) were employed, and 29.3% (95% CI, 9.0-55.3) lived independently. In adults without intellectual disability, proportions of individuals who were ambulant (72.6% [95% CI, 58.8-84.5]) and lived independently (90.0% [95% CI, 83.8-94.9]) were higher (P=.014 and P<.01, respectively). The Fatigue Severity Scale score was 4.1 (95% CI, 3.8-4.4). Epilepsy (28.8% [95% CI, 20.1-38.4]) and asthma (28.3% [95% CI, 18.7-38.9]) were especially prevalent comorbidities.

      Conclusions

      The present systematic review and meta-analysis on the epidemiology of adults with CP provided state-of-the-art knowledge on the most frequently studied outcomes. On average, adults with CP are fatigued, and a majority experience pain, are ambulant, and have little or no difficulty with manual ability. On average, 40% are employed and 30% live independently. More uniformity in assessment and reports is advised to improve knowledge on epidemiology and gain insight in more outcomes.

      Keywords

      List of abbreviations:

      BMI (body mass index), CI (confidence interval), CP (cerebral palsy), FSS (Fatigue Severity Scale), GMFCS (Gross Motor Function Classification System), ICF (International Classification of Functioning, Disability and Health), ID (intellectual disability), MACS (Manual Ability Classification System), SF-36 (Short Form-36 Health Survey)
      To read this article in full you will need to make a payment

      Purchase one-time access:

      Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
      One-time access price info
      • For academic or personal research use, select 'Academic and Personal'
      • For corporate R&D use, select 'Corporate R&D Professionals'

      Subscribe:

      Subscribe to Archives of Physical Medicine and Rehabilitation
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect

      References

        • Rosenbaum P.
        • Paneth N.
        • Leviton A.
        • et al.
        A report: the definition and classification of cerebral palsy April 2006.
        Dev Med Child Neurol Suppl. 2007; 109: 8-14
        • Odding E.
        • Roebroeck M.E.
        • Stam H.J.
        The epidemiology of cerebral palsy: incidence, impairments and risk factors.
        Disabil Rehabil. 2006; 28: 183-191
        • Paneth N.
        • Hong T.
        • Korzeniewski S.
        The descriptive epidemiology of cerebral palsy.
        Clin Perinatol. 2006; 33: 251-267
        • Maenner M.J.
        • Blumberg S.J.
        • Kogan M.D.
        • Christensen D.
        • Yeargin-Allsopp M.
        • Schieve L.A.
        Prevalence of cerebral palsy and intellectual disability among children identified in two U.S. National Surveys, 2011-2013.
        Ann Epidemiol. 2016; 26: 222-226
        • Access Economics
        The economic impact of cerebral palsy in Australia in 2007.
        Access Economics, Canberra2008
        • Benner J.L.
        • Noten S.
        • Limsakul C.
        • et al.
        Outcomes in adults with cerebral palsy: systematic review using the International Classification of Functioning, Disability and Health.
        Dev Med Child Neurol. 2019; 61: 1153-1161
        • Fortuna R.J.
        • Holub A.
        • Turk M.A.
        • Meccarello J.
        • Davidson P.W.
        Health conditions, functional status and health care utilization in adults with cerebral palsy.
        Fam Pract. 2018; 35: 661-670
        • Whitney D.G.
        • Hurvitz E.A.
        • Ryan J.M.
        • et al.
        Noncommunicable disease and multimorbidity in young adults with cerebral palsy.
        Clin Epidemiol. 2018; 10: 511-519
        • Turk M.A.
        • Logan L.R.
        • Ansoanuur F.
        Adults with childhood onset disabilities: a focused review of three conditions.
        Curr Phys Med Rehabil Rep. 2013; 1: 72-87
        • Benner J.L.
        • Hilberink S.R.
        • Veenis T.
        • Stam H.J.
        • van der Slot W.M.
        • Roebroeck M.E.
        Long-term deterioration of perceived health and functioning in adults with cerebral palsy.
        Arch Phys Med Rehabil. 2017; 98: 2196-2205
        • Opheim A.
        • Jahnsen R.
        • Olsson E.
        • Stanghelle J.K.
        Walking function, pain, and fatigue in adults with cerebral palsy: a 7-year follow-up study.
        Dev Med Child Neurol. 2009; 51: 381-388
        • Benner J.L.
        • Hilberink S.R.
        • Veenis T.
        • van der Slot W.M.A.
        • Roebroeck M.E.
        Course of employment in adults with cerebral palsy over a 14-year period.
        Dev Med Child Neurol. 2017; 59: 762-768
        • Schmidt A.K.
        • Van Gorp M.
        • Van Wely L.
        • et al.
        Autonomy in participation in cerebral palsy from chidhood to adulthood.
        Dev Med Child Neurol. 2020; 62: 363-371
        • van Gorp M.
        • Van Wely L.
        • Dallmeijer A.J.
        • et al.
        Long-term course of difficulty in participation of individuals with cerebral palsy aged 16 to 34 years: a prospective cohort study.
        Dev Med Child Neurol. 2019; 61: 194-203
        • Novak I.
        • Hines M.
        • Goldsmith S.
        • Barclay R.
        Clinical prognostic messages from a systematic review on cerebral palsy.
        Pediatrics. 2012; 130: e1285-e1312
        • Jonsson U.
        • Eek M.N.
        • Sunnerhagen K.S.
        • Himmelmann K.
        Cerebral palsy prevalence, subtypes, and associated impairments: a population-based comparison study of adults and children.
        Dev Med Child Neurol. 2019; 61: 1162-1167
        • WHO International
        Classification of Functioning, Disability and Health.
        ICF, Geneva2001
        • Ballester-Plane J.
        • Laporta-Hoyos O.
        • Macaya A.
        • et al.
        Cognitive functioning in dyskinetic cerebral palsy: its relation to motor function, communication and epilepsy.
        Eur J Paediatr Neurol. 2018; 22: 102-112
        • Laporta-Hoyos O.
        • Fiori S.
        • Pannek K.
        • et al.
        Brain lesion scores obtained using a simple semi-quantitative scale from MR imaging are associated with motor function, communication and cognition in dyskinetic cerebral palsy.
        Neuroimage Clin. 2018; 19: 892-900
        • Whitney D.G.
        • Hurvitz E.A.
        • Devlin M.J.
        • et al.
        Age trajectories of musculoskeletal morbidities in adults with cerebral palsy.
        Bone. 2018; 114: 285-291
        • Cremer N.
        • Hurvitz E.A.
        • Peterson M.D.
        Multimorbidity in middle-aged adults with cerebral palsy.
        Am J Med. 2017; 130: 744
        • Agustsson A.
        • Sveinsson T.
        • Pope P.
        • Rodby-Bousquet E.
        Preferred posture in lying and its association with scoliosis and windswept hips in adults with cerebral palsy.
        Disabil Rehabil. 2019; 41: 3198-3202
        • Alriksson-Schmidt A.
        • Hagglund G.
        • Rodby-Bousquet E.
        • Westbom L.
        Follow-up of individuals with cerebral palsy through the transition years and description of adult life: the Swedish experience.
        J Pediatr Rehabil Med. 2014; 7: 53-61
        • Rodby-Bousquet E.
        • Czuba T.
        • Hagglund G.
        • Westbom L.
        Postural asymmetries in young adults with cerebral palsy.
        Dev Med Child Neurol. 2013; 55: 1009-1015
        • van Gorp M.
        • Roebroeck M.E.
        • Swan Tan S.
        • et al.
        Activity performance curves of individuals with cerebral palsy.
        Pediatrics. 2018; (142)
        • van Meeteren J.
        • Nieuwenhuijsen C.
        • de Grund A.
        • Stam H.J.
        • Roebroeck M.E.
        • Transition Research Group South West Netherlands
        Using the manual ability classification system in young adults with cerebral palsy and normal intelligence.
        Disabil Rehabil. 2010; 32: 1885-1893
        • Nieuwenhuijsen C.
        • Donkervoort M.
        • Nieuwstraten W.
        • Stam H.J.
        • Roebroeck M.E.
        • Transition Research Group South West Netherlands
        Experienced problems of young adults with cerebral palsy: targets for rehabilitation care.
        Arch Phys Med Rehabil. 2009; 90: 1891-1897
        • van der Dussen L.
        • Nieuwstraten W.
        • Roebroeck M.
        • Stam H.J.
        Functional level of young adults with cerebral palsy.
        Clin Rehabil. 2001; 15: 84-91
        • Kirk H.
        • Geertsen S.S.
        • Lorentzen J.
        • Krarup K.B.
        • Bandholm T.
        • Nielsen J.B.
        Explosive resistance training increases rate of force development in ankle dorsiflexors and gait function in adults with cerebral palsy.
        J Strength Cond Res. 2016; 30: 2749-2760
        • McPhee P.G.
        • Gorter J.W.
        • Cotie L.M.
        • Timmons B.W.
        • Bentley T.
        • MacDonald M.J.
        Descriptive data on cardiovascular and metabolic risk factors in ambulatory and non-ambulatory adults with cerebral palsy.
        Data Brief. 2015; 5: 967-970
        • McPhee P.G.
        • Gorter J.W.
        • Cotie L.M.
        • Timmons B.W.
        • Bentley T.
        • MacDonald M.J.
        Associations of non-invasive measures of arterial structure and function, and traditional indicators of cardiovascular risk in adults with cerebral palsy.
        Atherosclerosis. 2015; 243: 462-465
        • Slaman J.
        • van den Berg-Emons H.J.
        • van Meeteren J.
        • et al.
        A lifestyle intervention improves fatigue, mental health and social support among adolescents and young adults with cerebral palsy: focus on mediating effects.
        Clin Rehabil. 2015; 29: 717-727
        • Russchen H.A.
        • Slaman J.
        • Stam H.J.
        • et al.
        Focus on fatigue amongst young adults with spastic cerebral palsy.
        J Neuroeng Rehabil. 2014; 11: 161
        • Slaman J.
        • Roebroeck M.
        • van der Slot W.
        • et al.
        Can a lifestyle intervention improve physical fitness in adolescents and young adults with spastic cerebral palsy? A randomized controlled trial.
        Arch Phys Med Rehabil. 2014; 95: 1646-1655
        • Ryan J.M.
        • Crowley V.E.
        • Hensey O.
        • McGahey A.
        • Gormley J.
        Waist circumference provides an indication of numerous cardiometabolic risk factors in adults with cerebral palsy.
        Arch Phys Med Rehabil. 2014; 95: 1540-1546
        • Morgan P.E.
        • Soh S.E.
        • McGinley J.L.
        Health-related quality of life of ambulant adults with cerebral palsy and its association with falls and mobility decline: a preliminary cross sectional study.
        Health Qual Life Outcomes. 2014; 12: 132
        • Morgan P.
        • McGinley J.
        Performance of adults with cerebral palsy related to falls, balance and function: a preliminary report.
        Dev Neurorehabil. 2013; 16: 113-120
        • Reddihough D.S.
        • Jiang B.
        • Lanigan A.
        • Reid S.M.
        • Walstab J.E.
        • Davis E.
        Social outcomes of young adults with cerebral palsy.
        J Intellect Dev Disabil. 2013; 38: 215-222
        • van der Slot W.M.
        • Roebroeck M.E.
        • Nieuwenhuijsen C.
        • et al.
        Cardiovascular disease risk in adults with spastic bilateral cerebral palsy.
        J Rehabil Med. 2013; 45: 866-872
        • van der Slot W.M.
        • Nieuwenhuijsen C.
        • van Den Berg-Emons R.J.
        • et al.
        Chronic pain, fatigue, and depressive symptoms in adults with spastic bilateral cerebral palsy.
        Dev Med Child Neurol. 2012; 54: 836-842
        • van der Slot W.M.
        • Nieuwenhuijsen C.
        • van den Berg-Emons R.J.
        • et al.
        Participation and health-related quality of life in adults with spastic bilateral cerebral palsy and the role of self-efficacy.
        J Rehabil Med. 2010; 42: 528-535
        • Opheim A.
        • Jahnsen R.
        • Olsson E.
        • Stanghelle J.K.
        Physical and mental components of health-related quality of life and musculoskeletal pain sites over seven years in adults with spastic cerebral palsy.
        J Rehabil Med. 2011; 43: 382-387
        • Jahnsen R.
        • Villien L.
        • Egeland T.
        • Stanghelle J.K.
        • Holm I.
        Locomotion skills in adults with cerebral palsy.
        Clin Rehabil. 2004; 18: 309-316
        • Jahnsen R.
        • Villien L.
        • Aamodt G.
        • Stanghelle J.K.
        • Holm I.
        Musculoskeletal pain in adults with cerebral palsy compared with the general population.
        J Rehabil Med. 2004; 36: 78-84
        • Jahnsen R.
        • Villien L.
        • Stanghelle J.K.
        • Holm I.
        Coping potential and disability--sense of coherence in adults with cerebral palsy.
        Disabil Rehabil. 2002; 24: 511-518
        • Maltais D.B.
        • Dumas F.
        • Boucher N.
        • Richards C.L.
        Factors related to physical activity in adults with cerebral palsy may differ for walkers and nonwalkers.
        Am J Phys Med Rehabil. 2010; 89: 584-597
        • Michelsen S.I.
        • Uldall P.
        • Hansen T.
        • Madsen M.
        Social integration of adults with cerebral palsy.
        Dev Med Child Neurol. 2006; 48: 643-649
        • Michelsen S.I.
        • Uldall P.
        • Kejs A.M.
        • Madsen M.
        Education and employment prospects in cerebral palsy.
        Dev Med Child Neurol. 2005; 47: 511-517
        • Engel J.M.
        • Jensen M.P.
        • Hoffman A.J.
        • Kartin D.
        Pain in persons with cerebral palsy: extension and cross validation.
        Arch Phys Med Rehabil. 2003; 84: 1125-1128
        • Gillett J.G.
        • Lichtwark G.A.
        • Boyd R.N.
        • Barber L.A.
        Functional capacity in adults with cerebral palsy: lower limb muscle strength matters.
        Arch Phys Med Rehabil. 2018; 99: 900-906
        • Lundh S.
        • Nasic S.
        • Riad J.
        Fatigue, quality of life and walking ability in adults with cerebral palsy.
        Gait Posture. 2018; 61: 1-6
        • Park M.W.
        • Kim W.S.
        • Bang M.S.
        • et al.
        Needs for medical and rehabilitation services in adults with cerebral palsy in Korea.
        Ann Rehabil Med. 2018; 42: 465-472
        • Peterson M.D.
        • Kamdar N.
        • Hurvitz E.A.
        Age-related trends in cardiometabolic disease among adults with cerebral palsy.
        Dev Med Child Neurol. 2019; 61: 484-489
        • Sienko S.E.
        An exploratory study investigating the multidimensional factors impacting the health and well-being of young adults with cerebral palsy.
        Disabil Rehabil. 2018; 40: 660-666
        • Smith K.J.
        • Peterson M.D.
        • O'Connell N.E.
        • et al.
        Risk of depression and anxiety in adults with cerebral palsy.
        JAMA Neurol. 2019; 76: 294-300
        • Daunter A.K.
        • Kratz A.L.
        • Hurvitz E.A.
        Long-term impact of childhood selective dorsal rhizotomy on pain, fatigue, and function: a case-control study.
        Dev Med Child Neurol. 2017; 59: 1089-1095
        • de Albuquerque Botura C.
        • Ames F.Q.
        • de Albuquerque Botura A.C.
        • Bersani-Amado L.E.
        • Bardini A.V.S.L.
        • Cuman R.K.N.
        Pain symptoms in patients with severe cerebral palsy: prevalence among patients with higher degree of locomotor impairment.
        Trop J Pharm Res. 2017; 16: 1431-1436
        • Hayward K.
        • Chen A.Y.
        • Forbes E.
        • Byrne R.
        • Greenberg M.B.
        • Fowler E.G.
        Reproductive healthcare experiences of women with cerebral palsy.
        Disabil Health J. 2017; 10: 413-418
        • Park E.Y.
        • Kim W.H.
        Prevalence of secondary impairments of adults with cerebral palsy according to gross motor function classification system.
        J Phys Ther Sci. 2017; 29: 266-269
        • Vukojević M.
        • Cvitković T.
        • Splavski B.
        • Ostojić Z.
        • Šumanović-Glamuzina D.
        • Šimić J.
        Prevalence of intellectual disabilities and epilepsy in different forms of spastic cerebral palsy in adults.
        Psychiatr Danub. 2017; 29: 111-117
        • Yıldız N.
        • Akkoç Y.
        • Ersöz M.
        • et al.
        Cross-sectional study of urinary problems in adults with cerebral palsy: awareness and impact on the quality of life.
        Neurol Sci. 2017; 38: 1193-1203
        • Brunton L.
        • Hall S.
        • Passingham A.
        • Wulff J.
        • Delitala R.
        The prevalence, location, severity, and daily impact of pain reported by youth and young adults with cerebral palsy.
        J Pediatr Rehabil Med. 2016; 9: 177-183
        • Peterson M.D.
        • Ryan J.M.
        • Hurvitz E.A.
        • Mahmoudi E.
        Chronic conditions in adults with cerebral palsy.
        JAMA. 2015; 314: 2303-2305
        • Peterson M.D.
        • Haapala H.J.
        • Chaddha A.
        • Hurvitz E.A.
        Abdominal obesity is an independent predictor of serum 25-hydroxyvitamin D deficiency in adults with cerebral palsy.
        Nutr Metab (Lond). 2014; 11: 22
        • Huang I.C.
        • Wang Y.T.
        • Chan F.
        Employment outcomes of adults with cerebral palsy in Taiwan.
        Disabil Rehabil. 2013; 35: 228-235
        • Hamrah Nedjad J.
        • Jansson E.
        • Bartonek Å.
        Physical activity in a swedish youth and adult population with cerebral palsy.
        Eur J Physiother. 2013; 15: 70-77
        • Mesterman R.
        • Leitner Y.
        • Yifat R.
        • et al.
        Cerebral palsy—long-term medical, functional, educational, and psychosocial outcomes.
        J Child Neurol. 2010; 25: 36-42
        • Gaskin C.J.
        • Morris T.
        Physical activity, health-related quality of life, and psychosocial functioning of adults with cerebral palsy.
        J Phys Act Health. 2008; 5: 146-157
        • Andersson C.
        • Asztalos L.
        • Mattsson E.
        Six-minute walk test in adults with cerebral palsy. A study of reliability.
        Clin Rehabil. 2006; 20: 488-495
        • Sandström K.
        • Alinder J.
        • Öberg B.
        Descriptions of functioning and health and relations to a gross motor classification in adults with cerebral palsy.
        Disabil Rehabil. 2004; 26: 1023-1031
        • Strauss D.
        • Ojdana K.
        • Shavelle R.
        • Rosenbloom L.
        Decline in function and life expectancy of older persons with cerebral palsy.
        NeuroRehabilitation. 2004; 19: 69-78
        • Andersson C.
        • Mattsson E.
        Adults with cerebral palsy: a survey describing problems, needs, and resources, with special emphasis on locomotion.
        Dev Med Child Neurol. 2001; 43: 76-82
        • Bottos M.
        • Feliciangeli A.
        • Sciuto L.
        • Gericke C.
        • Vianello A.
        Functional status of adults with cerebral palsy and implications for treatment of children.
        Dev Med Child Neurol. 2001; 43: 516-528
        • Furukawa A.
        • Iwatsuki H.
        • Nishiyama M.
        • Nii E.
        • Uchida A.
        A study on the subjective well-being of adult patients with cerebral palsy.
        J Phys Ther Sci. 2001; 13: 31-35
        • Hodgkinson I.
        • Jindrich M.L.
        • Duhaut P.
        • Vadot J.P.
        • Metton G.
        • Bérard C.
        Hip pain in 234 non-ambulatory adolescents and young adults with cerebral palsy: a cross-sectional multicentre study.
        Dev Med Child Neurol. 2001; 43: 806-808
        • Maruishi M.
        • Mano Y.
        • Sasaki T.
        • Shinmyo N.
        • Sato H.
        • Ogawa T.
        Cerebral palsy in adults: independent effects of muscle strength and muscle tone.
        Arch Phys Med Rehabil. 2001; 82: 637-641
        • Murphy K.P.M.
        • Molnar G.E.
        • Lankasky K.
        Employment and social issues in adults with cerebral palsy.
        Arch Phys Med Rehabil. 2000; 81: 807-811
        • Aaronson N.K.
        • Muller M.
        • Cohen P.D.
        • et al.
        Translation, validation, and norming of the Dutch language version of the SF-36 Health Survey in community and chronic disease populations.
        J Clin Epidemiol. 1998; 51: 1055-1068
        • Krupp L.B.
        • LaRocca N.G.
        • Muir-Nash J.
        • Steinberg A.D.
        The fatigue severity scale. Application to patients with multiple sclerosis and systemic lupus erythematosus.
        Arch Neurol. 1989; 46: 1121-1123
        • Eliasson A.C.
        • Krumlinde-Sundholm L.
        • Rosblad B.
        • et al.
        The Manual Ability Classification System (MACS) for children with cerebral palsy: scale development and evidence of validity and reliability.
        Dev Med Child Neurol. 2006; 48: 549-554
        • UNESCO Institute for Statistics
        International Standard Classification of Education (ISCED) 2011.
        UNESCO Institute for Statistics, Montreal2012
        • Lemmens J.
        • van Engelen E.I.S.M.
        • Post M.W.M.
        • Beurskens A.J.H.M.
        • Wolters P.M.J.C.
        • de Witte L.P.
        Reproducibility and validity of the Dutch Life Habits Questionnaire (LIFE-H 3.0) in older adults.
        Clin Rehabil. 2007; 21: 853-862
        • Collin C.
        • Wade D.T.
        • Davies S.
        • Horne V.
        The Barthel ADL Index: a reliability study.
        Int Disabil Stud. 1988; 10: 61-63
        • Linacre J.M.
        • Heinemann A.W.
        • Wright B.D.
        • Granger C.V.
        • Hamilton B.B.
        The structure and stability of the Functional Independence Measure.
        Arch Phys Med Rehabil. 1994; 75: 127-132
        • Russell D.J.
        • Rosenbaum P.L.
        • Cadman D.T.
        • Gowland C.
        • Hardy S.
        • Jarvis S.
        The gross motor function measure: a means to evaluate the effects of physical therapy.
        Dev Med Child Neurol. 1989; 31: 341-352
        • Graham H.K.
        • Harvey A.
        • Rodda J.
        • Nattrass G.R.
        • Pirpiris M.
        The Functional Mobility Scale (FMS).
        J Pediatr Orthop. 2004; 24: 514-520
        • Izumida S.
        • Inoue S.
        Assessment of treatment for low back pain.
        J Jpn Orthop Assoc. 1986; 60: 391-394
        • Palisano R.J.
        • Hanna S.E.
        • Rosenbaum P.L.
        • Russell D.J.
        • Walter S.D.
        • Wood E.P.
        • et al.
        Validation of a model of gross motor function for children with cerebral palsy.
        Phys Ther. 2000; 80: 974-985
        • DerSimonian R.
        • Laird N.
        Meta-analysis in clinical trials.
        Control Clin Trials. 1986; 7: 177-188
        • Freeman M.F.
        • Tukey J.W.
        Transformations related to the angular and the square root.
        The Ann Math Stat. 1950; 21: 607-611
        • Miller J.J.
        The inverse of the Freeman-Tukey double arcsine transformation.
        Am Stat. 1978; 32: 138
        • Higgins J.P.
        • Thompson S.G.
        • Deeks J.J.
        • Altman D.G.
        Measuring inconsistency in meta-analyses.
        BMJ. 2003; 327: 557-560
        • Himmelmann K.
        • Beckung E.
        • Hagberg G.
        • Uvebrant P.
        Gross and fine motor function and accompanying impairments in cerebral palsy.
        Dev Med Child Neurol. 2006; 48: 417-423
        • To T.
        • Stanojevic S.
        • Moores G.
        • et al.
        Global asthma prevalence in adults: findings from the cross-sectional world health survey.
        BMC Public Health. 2012; 12: 204
        • van der Slot W.
        • Benner J.
        • Brunton L.
        • et al.
        Pain in adults with cerebral palsy: a systematic review and meta-analysis of individual participant data.
        Ann Phys Med Rehabil. 2020 Feb 13; ([Epub ahead of print])
        • Nahin R.L.
        Estimates of pain prevalence and severity in adults: United States, 2012.
        J Pain. 2015; 16: 769-780
        • Valko P.O.
        • Bassetti C.L.
        • Bloch K.E.
        • Held U.
        • Baumann C.R.
        Validation of the fatigue severity scale in a Swiss cohort.
        Sleep. 2008; 31: 1601-1607
        • Gross P.H.
        • Bailes A.F.
        • Horn S.D.
        • et al.
        Setting a patient-centered research agenda for cerebral palsy: a participatory action research initiative.
        Dev Med Child Neurol. 2018; 60: 1278-1284
        • Vogtle L.K.
        Pain in adults with cerebral palsy: impact and solutions.
        Dev Med Child Neurol. 2009; 51: 113-121
        • Brunton L.K.
        • McPhee P.G.
        • Gorter J.W.
        Self-reported factors contributing to fatigue and its management in adolescents and adults with cerebral palsy.
        Disabil Rehabil. 2019; 30: 1-7
        • Carnahan K.D.
        • Arner M.
        • Hagglund G.
        Association between gross motor function (GMFCS) and manual ability (MACS) in children with cerebral palsy. A population-based study of 359 children.
        BMC Musculoskelet Disord. 2007; 8: 50
        • Langerak N.G.
        • Hillier S.L.
        • Verkoeijen P.P.
        • Peter J.C.
        • Fieggen A.G.
        • Vaughan C.L.
        Level of activity and participation in adults with spastic diplegia 17-26 years after selective dorsal rhizotomy.
        J Rehabil Med. 2011; 43: 330-337
        • Donkervoort M.
        • Roebroeck M.
        • Wiegerink D.
        • van der Heijden-Maessen H.
        • Stam H.
        Determinants of functioning of adolescents and young adults with cerebral palsy.
        Disabil Rehabil. 2007; 29: 453-463
        • Jacobsen E.L.
        • Bye A.
        • Aass N.
        • et al.
        Norwegian reference values for the Short-Form Health Survey 36: development over time.
        Qual Life Res. 2018; 27: 1201-1212
        • Surveillance of Cerebral Palsy in Europe. Surveillance of cerebral palsy in Europe: a collaboration of cerebral palsy surveys and registers
        Surveillance of Cerebral Palsy in Europe (SCPE).
        Dev Med Child Neurol. 2000; 42: 816-824
        • Hurley D.S.
        • Sukal-Moulton T.
        • Msall M.E.
        • Gaebler-Spira D.
        • Krosschell K.J.
        • Dewald J.P.
        The cerebral palsy research registry: development and progress toward national collaboration in the United States.
        J Child Neurol. 2011; 26: 1534-1541
        • McPhee P.G.
        • Benner J.L.
        • Balemans A.C.J.
        • et al.
        Multimorbidity risk assessment in adolescents and adults with cerebral palsy: a protocol for establishing a core outcome set for clinical research and practice.
        Trials. 2019; 20: 176
        • Maulik P.K.
        • Mascarenhas M.N.
        • Mathers C.D.
        • Dua T.
        • Saxena S.
        Prevalence of intellectual disability: a meta-analysis of population-based studies.
        Res Dev Disabil. 2011; 32: 419-436