The epidemiology ofcerebral palsy

Reaching for the Stars

A Cerebral Palsy Conference for Parents & Caregivers

11 August 2007

Maxine M. Kuroda, Ph.D., M.P.H.

Measuring frequency, determining causal factors,and evaluating existing treatments

Definition of epidemiology

• Flagship science of public health• Gr. epi (among) + demos (people) + -ology

(discourse, treatise, ‘study of’)• The study of the distribution and

determinants of health-related states and events in populations, and the application of this study to control of health problems.

[Last JM. A dictionary of epidemiology. New York:Oxford University Press, 1983]

Descriptive v analytical

• Descriptive epidemiology provides information on patterns of disease occurrence in populations according to characteristics of the population, e.g., PERSON, PLACE, TIME.

• Analytical epidemiology tests causal hypotheses that are generated from data derived from descriptive studies.

Purposes

1. To determine the magnitude and impact of diseases or other conditions in populations or in selected subgroups

2. To learn more about the natural history and clinical course of diseases and of their pathogenesis in both the community and the individual

3. To detect changes in disease rates early on (surveillance)

4. To identify causes of disease (etiology)

[Modified from Kelsey JL, Thompson WD, Evans AS. Methods in observational epidemiology. New York: Oxford University Press, 1986]

Definition of cerebral palsy

“Cerebral palsy (CP) describes 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 behaviour, and/or by a seizure disorder.”

Bax M, Goldstein M, Rosenbaum P, Leviton A, Paneth N. Proposed definition and classification of cerebral palsy,April 2005. Dev Med Child Neurol 2005;47(8):571-6.

Significance of CP• Most costly of the clinically important birth

defects in the U.S.• Most common contributor to childhood

mortality among the developmental disabilities

• Most common and severe physical disability in childhood

• Most frequently used developmental disability to monitor the effects of perinatal and neonatal care in the U.S. and elsewhere

Where are research $ going?

Pediatric AIDS $2,319,672

Cutaneous anthrax $1,350,000

Autism $80,000

Cystic fibrosis $52,400

Cerebral palsy $1,200

Where are research $ going?

$0

$500,000

$1,000,000

$1,500,000

$2,000,000

$2,500,000

Pediatric AIDS

Cutaneous anthrax

Autism

Cystic fibrosis

Cerebral palsy

Prevalence of CP

Source: Stanley F, Blair E, Alberman E. How common are the cerebral palsies?In: Cerebral palsies: Epidemiology and causal pathways.Clinics in Developmental Medicine. London: MacKeith Press; 2000.

Numbers! Numbers! Numbers!

?312,947

500,000

1.4-2 million

Best guess?

Prevalence of CP by gender

0

0.5

1

1.5

2

Pro

po

rtio

n

Male Female

1.4

Clinical picture of CP

Extremity distribution: Tonal abnormality:Diplegia Spastic hypertoniaHemiplegia Dystonic hypertoniaQuadriplegia/triplegia Ataxic

HypotonicHyperkinetic

Chicago Cerebral Palsy Registry: Predecessors

• Few geographically-defined population-based studies in U.S.• CA births: Contra Costa, San Francisco,

San Mateo, Santa Clara (1983-1985)• GA births: Clayton, Cobb, DeKalb, Fulton,

Gwinnett (1975-1977)

• Only 1 population-based national study (dissertation)

Goals of Chicago CP Registry

• To collect data on the population-based prevalence, demographic characteristics, functional status, and natural history of CP

• To support research efforts of CP etiology, pathophysiological mechanisms, bioengineering assistance, functional status, activities, participation, and quality of life of individuals with CP

Methods• Development

• IRB approval• Enrollment packet

• Questionnaires (demographics, care and comfort, caregiver characteristics)• Chart abstraction (extremity distribution, tonal abnormality, GMFCS, MACS,

accompanying conditions)• Buccal swab for genotyping

• Registrar and abstractor training• Computer set up• Advisory Board membership

• Expansion• Collar counties• Participant follow-up• Computer software enhancements

• Evaluation• Rate of recruitment/enrollment• Proportion of total population enrolled

Questions? Questions? Questions?

• How does the demographic profile (gender, race/ethnicity) of American children with CP differ from that of children in other countries?

• What is the trajectory of development for children with CP?• How often do other disorders accompany CP (e.g., cognitive delays, seizures,

sensory deficits, speech disorders, behavior problems)?• What is the frequency of other illnesses (e.g., respiratory infections,

cardiovascular abnormalities) in children with CP? Hydrocephalus? How about G-tubes? Tracheotomy tubes?

• What is the frequency of CP due to injury occurring after ages 2-3 years (i.e., acquired CP)?

• What are the primary concerns of the caregivers? Are respite services available to caregivers?

• How often is Botox used in children with CP? In which extremities? How often is intrathecal baclofen used for spasticity management?

• How much therapy is received at school?• What are the levels of activities and participation of children with CP at home,

at school, and in the community?• How do parents rate their child’s quality of life? Do the ratings of parents differ

from that of their children (who are able to report)?• How can biomechanical devices assist in the therapy of children with CP?

A couple of ongoing studiesat RIC

• Association of apolipoprotein E (APOE) polymorphism with function and disability of children with cerebral palsy (CP)

• Assessing rehabilitation outcomes in children with cerebral palsy: The Care & Comfort Caregiver Questionnaire (CareQ)

Chromosome 19

13.3

13.2

13.1121111

12

13.1

13.2

13.3

13.4

APOE polymorphism

112 158 ε2 Cys Cys ε3 Cys Arg ε4 Arg Arg

Preliminary study

• More children with CP have at least one ε4 compared to control children.

• More children with severe CP have at least one ε4 compared to children with mild or moderate CP.

Kuroda MM, Weck ME, Sarwark JF, Hamidullah A, Wainwright MS.  Association of apolipoprotein E genotype and cerebral palsy in children.  Pediatrics  2007;119(2):306-13).

Proposed study

• Is motor function of children with CP different between those who do or do not have an ε4?

• Are activity restrictions and participation of children with CP different between those who do or do not have an ε4?

Care & Comfort Caregiver Questionnaire (CareQ)

• Although CP cannot be cured, therapies aimed at promoting as much independence as possible are available.

• Caregiver’s perceptions of ease of care are important to the child’s quality of life and are necessary when choosing treatment options and management.

• The original Care and Comfort Caregiver Questionnaire was designed at RIC with input from health care professionals, family members, and caregivers as an aid to goal setting, and could be used along with measures of functional outcome to evaluate the effect of treatment interventions.

Domains of the CareQ• Personal care

• Oral-facial hygiene• Dressing (shirts, pants,underpants)• Washing upper and lower body

• Positioning• Ease of sitting in/out of wheelchair• Ease of transfers• Applying orthotics (braces)

• Comfort• Pain or discomfort

• During diaper/clothing changes• While sitting in wheelchair• Prevent participation in family activities• Prevent participation in school programs or community activities

• Difficulty sleeping through the night• Use of pain control medicine

Methods

• Reliability (internal consistency) tested by Cronbach’s alpha

• Validity tested by Pearson or Spearman correlation (as appropriate) in order to compare scores on the CareQ with scores on another instrument that has been used in the clinics for a long time (WeeFIM)

Concluding comments

• Epidemiology– Importance of cerebral palsy as a field of

study– Some specifics of CP epidemiology– Identifying research needs

• On the docket at RIC– Chicago CP Registry– Apolipoprotein E (APOE)– Care & Comfort Caregiver Questionnaire