DIFFERENTIAL DIAGNOSIS OF ATYPICAL DEVELOPMENT IN
PRESCHOOL CHILDREN (AUTISM, MENTAL RETARDATION AND LANGUAGE DISORDERS)
Mark D. Simms, MD, MPH
Medical College of Wisconsin, Milwaukee, USA
Objective
of Presentation: To identify key factors that may
assist professionals in the accurate diagnosis of young children with
atypical patterns of behavior and development. Differential diagnosis
includes mental retardation, autistic spectrum disorder, developmental
language disorder and/or normal variation.
Background: Children who have atypical patterns of development are a
diagnostic challenge in the preschool years. Atypical behaviors include
those considered to be uncommon, such as perseveration on specific
activities, adherence to strict daily rituals, aloofness, and echolalia.
Atypical patterns are characterized by deviations in the order of skill
acquisition, discrepancies among areas of development, or regression and
loss of previously established abilities. DSM-IV and ICD-10 definitions of
mental retardation, autism and language disorders are often not helpful for
young children because of the non-specific nature of the presenting
symptoms. Long-range prognosis and treatment efficacy are dependent on the
etiology and natural history of the underlying disorder.
Results: Medical diagnostic
tests may identify a neurological basis for a child¡¯s disability but are
generally not helpful in determining a developmental diagnosis. Knowledge
of the prevalence rates of developmental disorders and specific family/genetic
history, evaluation of non-verbal cognitive abilities and speech-language
abilities, structured observation of social interaction patterns, and
comprehensive physical and neurological examination are essential
components of the diagnostic process. The presence of joint social
attention, affective reciprocity, imitation and pretend play, appropriate
to the child¡¯s mental age, help to distinguish between autism and language
disorders or uncomplicated mental retardation. In some cases, response to
therapeutic interventions and reevaluation may be required before an
accurate diagnosis can be established.