Assessment & Research

Estimating the prevalence of cerebral palsy in Taiwan: A comparison of different case definitions.

Chang et al. (2015) · Research in developmental disabilities 2015
★ The Verdict

A Taiwan team showed CP counts can double just by tweaking the case rule—use three specialist notes plus age four to keep reports steady.

✓ Read this if BCBAs who write evaluation reports or sit on state surveillance teams.
✗ Skip if Clinicians only running direct therapy with no data duties.

01Research in Context

01

What this study did

The team counted how many kids in Taiwan have cerebral palsy.

They tried four different rule sets for who counts as a case.

Each rule needed a different number of doctor visits and a different age cutoff.

02

What they found

The CP rate swung from 1.3 to 4.1 kids per 1,000.

The tightest rule—three specialist notes plus age four—gave 3.2 per 1,000.

That number sits above most earlier world reports.

03

How this fits with other research

Van Naarden Braun et al. (2008) also used big health files and saw strong CP risk in multiple births.

Spanoudis et al. (2011) did the same math for autism in San Francisco and got 4.7 per 1,000.

Both papers show one key point: change the rules and the count moves.

Lung et al. (2018) mined the same Taiwan files for autism and found no ART link—proof the same data lake can give clean CP or autism answers when you hold the rule set steady.

04

Why it matters

When you read a prevalence number, always ask what rule made it.

Pick one clear rule—three docs plus age four—and stick with it in your reports.

That small move keeps your data in line with Taiwan’s high-quality count and makes team talks with doctors and families simpler.

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→ Action — try this Monday

Add one line to your next report that states the exact rule you used to decide a child counts as having CP.

02At a glance

Intervention
not applicable
Design
other
Population
other
Finding
not reported

03Original abstract

The estimated prevalence of cerebral palsy (CP) worldwide ranged from 0.74 to 3.6 per 1000 live births according to different studies, which may be due to different data sources and case definitions used. We used a representative sample of one million patients (about 1/23 of total population) covered by Taiwan's National Health Insurance (NHI) to estimate the prevalence using different case definitions. Eight years of NHI Research Database claims data for all children born between 1996 and 2000 were reviewed for CP diagnoses. The estimated prevalence of CP (cases per 1000 live births) varied from 4.1 to 1.3 for different case definitions. For a minimum age of 4 years old at diagnosis, a diagnosis made by specialists (pediatricians and physicians of physical medicine and rehabilitation), and the CP diagnosis was mentioned at least three times in claims data, the mean estimated prevalence of CP was 3.2 (95% CI 2.8-3.7). According to this definition, which is most compatible with previous studies, the estimated prevalence in Taiwan was 3.4 (95% CI 2.8-4.0) for boys and 3.1 (95% CI 2.5-3.7) for girls, significantly higher than that in other countries. Additional studies are needed to determine the reasons of higher prevalence in Taiwan.

Research in developmental disabilities, 2015 · doi:10.1016/j.ridd.2014.10.001