Hasil penelitian sebelumnya menyatakan bahwa terdapat perbedaan ciri-ciri morfologik pada beberapa tingkat retardasi mental (RM). Penelitian tersebut umumnya di lakukan pada penderita sindroma Down (SD). Penelitian ini bertujuan untuk mengetahui perbedaan indeks sefalometri dan tangan menurut tingkat RM primer. Pada penelitian ini digunakan sampel yang berjumlah 300 anak laki-laki yang berasal dari Sekolah Luar Biasa dan 100 anak dari Sekolah Dasar sebagai kelompok kontrol. Kriteria sampel adalah berusia 7 - 12 tahun, memiliki ciri-ciri penderita SD dan data kesehatan ibu dan anak menunjukkan RM primer. Pada penelitian ini, telah dilakukan pengukuran dengan menggunakan metode Martin pada masing-masing sampel, lalu hasil pengukuran diolah dalam bentuk indeks sefalometri dan tangan. Hasil penelitian ini memperihatkan bahwa indeks sefalometri dan tangan pada penderita RM ringan dan RM sedang tidak berbeda bermakna secara statistik dibandingkan kontrol (p > 0,05). Sedangkan RM berat berbeda bermakna dibandingkan kontrol (p < 0,05). Hal ini kemungkinan disebabkan oleh sampel pada RM ringan berasal dan penderita SD tertier atau SD kuarterner, RM sedang dapat berasal dari pendetita SD tertier atau SD kuarterner, dapat juga dari penderita phenylketonuria (PKU) atau pengaruh pranatal yang tidak jelas; RM berat berasal dari penderita SD primer atau SD sekunder.

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Cephalometric and Hand Indices on Boys with Several Primary Mental Retardation StagesSome early researches suggested that there were morphological characteristic differences on several mental retardation (MR) stages. The subjects of those researches were mostly Down syndrome (DS) patients. This study was conducted to assess the difference of cephalometric and hand indices on primary MR stages. The subjects of the study were 300 boys from the abnormal schools and 100 boys from the elementary school as a control group. The criterions of the subjects, were 7-12 years old, had DS characters and the medical record showed that there were primary MR.

In this study, measurement on each subject used Martin's methods, then the results were calculated to be cephalometric and hand indices. The results of this study indicated that there were no significant cephalometric and hand indices difference (p > 0,05) between the mild, moderate MR and the control groups. But there was significant cephalometric and hand indices difference (p < 0,05) between the severe MR and the control group. The possibilities of these results were the subjects of this study which the mild stage of MR was derived from either tertiary or quaternary DS patients; the moderate stage of MR might be derived from either tertiary or quaternary DS patients as well as phenylketonuria (PKU) patients or unknown early neonatal influence patients; and the severe stage of MR was derived from either primary or secondary DS patients.