Auditory laterality and selective attention: normal performance in patients with early-onset schizophrenia.

In this study, auditory laterality and selective attention were examined in patients with early-onset schizophrenia using a dichotic listening (DL) test. Deficient performance on this test has repeatedly been found in adult patients with chronic schizophrenia, indicating abnormalities in left hemisphere function. The hypothesis in the present study was that subjects with early-onset schizophrenia manifest deficits in DL test performance similar to adult chronic patients. A group of 19 patients with early-onset schizophrenia were compared with a group of 20 adolescents with attention-deficit hyperactivity disorder and a group of 30 normal adolescents. Results indicated no significant differences between the three groups on any of the measures. Alternative hypotheses are put forth to explain the findings, among them that deficits in DL performance may be secondary to long-time illness and/or drug treatment, and that these deficits may become apparent only after interaction with maturational neurodevelopmental changes during adolescence.

No vigilance deficit found in either young schizophrenic or ADHD subjects.

Vigilance deficits have been found in both schizophrenic and ADHD subjects. The two patient groups have never been directly compared on any vigilance measure, however. In the present study 20 early-onset schizophrenics were compared to 20 ADHD adolescents on a Degraded Stimulus Continuous Performance Test (DS-CPT). A comparison group of 30 normal adolescents was also included. Results showed no significant differences between the three groups on any of the DS-CPT measures. Different hypotheses are put forth to explain the findings, among them that the task may be insensitive to identifying sustained attention deficits in adolescent populations.

Response to methylphenidate in boys with attention-deficit hyperactivity disorder.

The response to methylphenidate was examined in 36 boys, aged 7-11 y, with attention-deficit hyperactivity disorder (ADHD) in a double-blind, placebo-controlled, crossover design. Hyperactivity and conduct problems were significantly reduced during methylphenidate treatment. Stimulant medication was associated with improvements on tests of sustained attention, working memory and motor steadiness. When individual changes were studied, it was found that 83% showed a significant improvement in their hyperactivity at home or at school, and for 60% their levels of hyperactive behaviour were within the normal range. High levels of hyperactivity at school and relatively low age were significant predictors of normalization of hyperactivity in at least one setting. However, these predictors could only classify correctly 71% of the children. In clinical practice a trial with stimulants is indicated in ADHD children who show symptoms that are sufficiently severe to cause impairment at home and at school.