Similarities and differences between learning abilities, "pure" learning disabilities, "pure" ADHD and comorbid ADHD with learning disabilities.
This research pursues the crucial question of the differentiation of preadolescents with "Pure" ADHD, comorbid ADHD with learning disabilities, "Pure" learning disabilities and age-matched normal controls. For this purpose, Topographic Mapping of Event-Related Brain Potentials (ERPs) to a Memory Workload Paradigm with visually presented words, Bilateral Electrodermal Activity during cognitive workload and Mangina-Test performance were used. The analysis of Topographic distribution of amplitudes revealed that normal preadolescents were significantly different from "Pure" ADHD (P<0.0001), "Pure" learning disabilities (P<0.0001), and comorbid ADHD with learning disabilities (P<0.0009), by displaying enhanced prefrontal and frontal negativities (N450). In contrast, preadolescents with "Pure" ADHD and comorbid ADHD with learning disabilities have shown a marked reduction of prefrontal and frontal negativities (N450). As for the "Pure" Learning Disabled preadolescents, very small positivities (P450) in prefrontal and frontal regions were obtained as compared to the other pathological groups. Bilateral Electrodermal Activity during cognitive workload revealed a significant main effect for groups (P<0.00001), Left versus Right (P=0.0029) and sessions (P=0.0136). A significant main effect for the Mangina-Test performance which separated the four groups was found (P<0.000001). Overall, these data support the existence of clear differences and similarities between the pathological preadolescent groups as opposed to age-matched normal controls. The psychophysiological differentiation of these groups, provides distinct biological markers which integrate central, autonomic and neuropsychometric variables by targeting the key features of these pathologies for diagnosis and intervention strategies and by providing knowledge for the understanding of normal neurocognitive processes and functions.
Cognitive Psychophysiology Laboratory, Montreal Research and Treatment Center for Learning Abilities and Disabilities, 3587 University Street, Montreal, Quebec, Canada. mcgill@ca.inter.net
Constantine A
CA
Mangina
Helen
H
Beuzeron-Mangina
D001289:Attention Deficit Disorder with Hyperactivity / Q000150:complications / Q000523:psychology*; D001931:Brain Mapping; D002648:Child; D003071:Cognition / Q000502:physiology; D005071:Evoked Potentials / Q000502:physiology; D005712:Galvanic Skin Response / Q000502:physiology; D006801:Humans; D007858:Learning / Q000502:physiology*; D007859:Learning Disabilities / Q000150:complications / Q000523:psychology*; D008297:Male; D008568:Memory / Q000502:physiology; D009483:Neuropsychological Tests; D011569:Psychiatric Status Rating Scales; D011597:Psychomotor Performance / Q000502:physiology