Aetiology of intellectual disability--the Finnish classification: development of a method to incorporate WHO ICD-10 coding.
A simple timing-based tree helps clinicians pick the right ICD-10 code and explain ID causes to families.
01Research in Context
What this study did
Finnish doctors built a tree-shaped chart. It sorts ICD-10 codes for intellectual disability by when the brain injury happened.
They used the chart for 18 years. Clinicians picked a branch, found the code, and gave families a clear reason for the diagnosis.
What they found
The tree made talks with families faster. Doctors could point to a spot on the page and say, "This is why."
How this fits with other research
Tassé et al. (2013) later wrote the AAIDD rules for ICD-11. They kept the same goal—clear ID labels—but dropped the tree shape for plainer wording.
Kittler et al. (2004) showed 24 % of adults still had no cause listed. Their work says the Finnish tree is useful, but we must keep testing even after childhood.
Lin et al. (2009) tracked Taiwan’s registry with similar timing groups. Birth-related causes went down while disease causes rose, proving the tree can spot population shifts if countries share data.
Why it matters
You can borrow the timing idea today. When you write an assessment, add one line: pre-birth, birth, or after-birth injury. That single tag helps doctors, teachers, and families speak the same language and keeps the door open for genetic counseling later.
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02At a glance
03Original abstract
The present authors made an attempt to ease the diagnostic work of physicians who have patients with intellectual disability by creating an aetiological classification system based on the time and mechanism of injury to the central nervous system (CNS). The current paper presents the work-up needed for understanding at least the timing of the causative factor/factors. The timing principle opens a direct course to family counselling. This method has been very well accepted during its 18 years of use in Finland, and therefore, it was felt that it would be helpful to organize the relevant ICD-10 diagnoses according to the timing principle. This method has been published as a manual. An image of a tree became the obvious metaphor for this system. The genetic category forms the main root and stem, from which multiple branched roots and limbs emerge. The individual diagnoses appear as root nodules and leaves. The system is flexible, making it possible to add new branches for groups of diagnoses when improved diagnostic methods create these options (e.g. microdeletions). The aetiological diagnoses change accordingly. Over the course of further development, new incidents damaging the CNS may affect the functional level of an individual and require additional diagnoses. It is a constant challenge for physicians to keep the diagnoses of their patients up to date. The image of the tree helps professionals to think in terms of timing, and thus, makes family counselling easier. It is also helpful in the education of medical professionals.
Journal of intellectual disability research : JIDR, 1999 · doi:10.1046/j.1365-2788.1999.00197.x