[Neurological soft signs in pervasive developmental disorders]

Many studies have focused on specific motor signs in autism and Asperger's syndrome, but few has been published on the complete range of neurological soft signs (NSS) in children with pervasive developmental disorder (PDD). Scarce are the studies evaluating NSS in children suffering from PDD not otherwise specified (PDDNOS).

This study compared performance of 11 autistic children (AD) and 10 children with PDDNOS, with controls matched on age, sex and cognitive performance on Krebs et al.'s NSS scale. Because of the duration of the assessments and specific difficulties encountered in managing some items, an adaptation of the scale had to be made during a pilot study with the agreement of the author. To be eligible, patients had to meet the following inclusion criteria: an age range of 6-16 years, a diagnosis of autistic disorder or PDDNOS based on the DSM IV criteria (American Psychiatric Association 1994). The autism diagnostic interview-revised (ADI-R) was used in order to confirm the diagnosis and to evaluate the association of the symptoms to the severity of the NSS. The childhood autism rating scale (CARS) was completed for the patients in order to evaluate symptoms at the time of the NSS examination. Cognitive ability was assessed with Raven's progressive matrices. Were excluded patients with: history of cerebral palsy, congenital anomaly of the central nervous system, epilepsy, known genetic syndrome, tuberous sclerosis, neurofibromatosis, antecedent of severe head trauma, Asperger's syndrome, obvious physical deformities or sensory deficits that would interfere with neurological assessment, deep mental retardation and recent or chronic substance use or abuse. Healthy controls shared the same exclusion criteria, with no personal history of neurological, psychiatric disorder or substance abuse, no family history of psychiatric disorder and normal or retardation in schooling. All study procedures were approved by the local Ethics Committee (Comité d'éthique, Razi Hospital), according to the declaration of Helsinki.

There was no difference between patients and controls with respect to sex, age and cognitive function. All children had an IQ higher than 81. Significant differences were found between AD children and control group in the motor integration function and sensory integration function. Different NSS scores were significantly higher in the PDDNOS group than in controls: the total scores, motor coordination, motor integration function, sensory integration and abnormal movements. Lower performance in motor coordination skills was associated with higher ADI-R communication score in the AD group. No relationship was found between NSS and CARS' total sore.

This study confirms the impaired neurological functioning in autistic as well as PDDNOS children. The association of motor impairment with autistic symptoms highlights the argument that motor control problems can be part of the autism spectrum disorders. The lack of relationship between NSS and intellectual aptitude in the clinical sample provides new elements for the neurodevelopment model of the autism spectrum.