In a target discrimination task, trials with incorrect responses elicit event-related potentials (ERPs) that include an error-related negativity (ERN or Ne) and a later error-positivity (Pe). Substantial evidence points to the anterior cingulate cortex as the source generator of the ERN. We examined the development of ERP component morphology, amplitude and latency to processing of correct and incorrect responses in 124 children, 7 to 18 years of age, and 27 adults, 19 through 25 years of age. The ERN and Pe were recorded during a standard 480-trial visual flanker task. As expected, response times decreased significantly with age. The ERN amplitude in error trials increased with age, although this was qualified by a nonlinear change as well. The Pe amplitude did not change with age. In correct trials, most participants produced a small negativity corresponding to the timing of the ERN in error trials. This correct-response negativity (CRN) amplitude was larger in children than in adults. Results are discussed with respect to continued maturation of the anterior cingulate cortex and prefrontal cortex into young adulthood.

LSVT-X successfully increased vocal SPL (which was consistent with improvements following traditional LSVT), decreased perceived voice handicap, and improved functional speech in individuals with PD. Further large-scale research is required to truly establish LSVT-X efficacy.

The efficacy of screening 2-year-old children for language delay using a parent-report questionnaire was investigated in three studies. The Language Development Survey (Rescorla, 1989) was mailed to 650 families at the time of their child's second birthday. Fifty-three percent of the surveys received by parents were completed and returned. Screening outcomes were then compared, in double-blind fashion, with the results of comprehensive clinical evaluations at ages 2 (N = 64) and 3 (N = 36). Parents' report of the size of their children's expressive vocabularies was highly correlated with clinical language measures at age 2. Children who screened positive performed significantly poorer than children who screened negative on standardized language tests and on measures taken from spontaneous conversation. The screening program demonstrated excellent sensitivity and specificity for identifying language delay at age 2 but somewhat lower levels for predicting developmental status one year later.

These results present empirical evidence that children with SPD display unique brain processing mechanisms compared to children who are typically developing and provide external validity for the diagnosis of SPD.

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