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Biomedical subjects

J T Brumaghim

Publications and source records attributed to J T Brumaghim.

11 recordsLinked to original sources
PubMed1992

Methylphenidate reduces abnormalities of stimulus classification in adolescents with attention deficit disorder.

Forty-eight adolescents with attention deficit disorder (ADD) received placebo and methylphenidate (M = 35.21 mg/day) for 3 consecutive weeks each. ADD patients who received placebo in the first phase of treatment were compared with unmedicated normal adolescents. ADD and normal adolescents did not differ in slope of reaction time as a function of memory load in a Sternberg (1969) memory task. These results may be interpreted as reflecting normal rates of memory search in ADD. However, in comparison with normal subjects, ADD subjects made disproportionately more errors to targets and lacked faster latencies of the P3b component of event-related potentials for targets than nontargets. These findings suggest abnormalities in stimulus classification. Methylphenidate did not affect ADD patients' rates of memory search, but it did reduce misclassifications of targets at high memory loads. The drug also evoked the normal pattern of slower P3b latencies for nontargets by shortening latencies for targets. Thus the stimulant reduced ADD adolescents' abnormalities in stimulus classification.

Adolescent↗
PubMed1992

Effects of sustained-release and standard preparations of methylphenidate on attention deficit disorder.

Nineteen children with attention deficit disorder (ADD) participated in a double-blind trial consisting of four 2-week phases: sustained-release methylphenidate (MPH); standard MPH; a combination of standard and sustained-release MPH; and placebo. Pharmacological treatments were evaluated by means of parent and teacher ratings and open-ended comments, examiner ratings, and patients' performance and event-related potentials during Continuous Performance and Paired-Associate Learning Tests. Results revealed that the MPH conditions were superior to placebo and comparable to one another. Within the limited time frame of the research, the findings suggest comparable effectiveness for sustained-release and standard preparations of MPH.

Attention Deficit Disorder with Hyperactivity↗
PubMed1991

Methylphenidate speeds evaluation processes of attention deficit disorder adolescents during a continuous performance test.

Forty-six Attention Deficit Disorder (ADD) adolescents took a Continuous Performance Test (CPT) under placebo and methylphenidate (35.33 mg/day). The task required pressing one button for targets (p = .133), and another button for nontargets. Subjects displayed a strong bias to make the more frequent negative response before completely evaluating stimuli. Consistent with this assumption, subjects responded faster (by an average of 87 ms) to nontargets than to targets. Methylphenidate increased accuracy and speeded reaction times (RTs) to targets. The drug also increased the amplitude of the P3b component of the event-related potential for nontargets and shortened the latency of P3b for both targets and nontargets. These results suggest increased capacity allocation to and faster evaluation of task stimuli. Finally, the stimulant lengthened relative motor processing time (RT-P3b latency) for nontargets, a finding implying that response processing was accomplished with the benefit of earlier completion of evaluation processes for these stimuli.

Adolescent↗
PubMed1990

Clinical effects of a controlled trial of methylphenidate on adolescents with attention deficit disorder.

Forty-eight attention deficit disorder patients, 12 to 18 years old and without previous stimulant therapy, received a double-blind trial of methylphenidate and placebo for 3 weeks each. Stimulant treatment produced mild side effects and weight reduction. Methylphenidate significantly reduced teachers' and parents' ratings of hyperactivity, inattention, and oppositionality. In addition, patients rated themselves as clinically improved and reported elevated subjective mood during stimulant therapy. Treatment benefits were comparable for patients with and without concurrent conduct or oppositional disorder as well as those with and without past or present depressive disorders. These results support the continued effectiveness of stimulant therapy for attention deficit disorder in adolescence. However, the magnitude of clinical effectiveness reported was smaller than previously found in younger patients.

Adolescent↗
PubMed1990

Effects of methylphenidate on processing negativities in patients with attention-deficit hyperactivity disorder.

This study compared the impact of methylphenidate on patients with Attention-deficit Hyperactivity Disorder (ADHD) with and without aggressive/noncompliant features in an oddball test consisting of a randomly ordered series of loud (frequent) tones, soft (rare) tones, bright (frequent) lights, and dim (rare) lights. In alternate conditions, subjects were required to respond to either the rare tones or the rare lights. These tasks were administered in a drug-free baseline session and after a counterbalanced treatment of 14 days each of methylphenidate (0.3 mg/Kg b.i.d.) and placebo (lactose b.i.d.). In comparison with placebo, methylphenidate resulted in greater accuracy and speed of reactions to targets of both modalities. The amplitude of N1 to auditory nontargets was larger when the target was a rare tone as opposed to a rare light, and this attention-related effect was increased by methylphenidate. The same differential amplitude enhancement by stimulant treatment was found for an early area measure of difference ERPs. In contrast, for N1 to visual nontargets the effect of selective attention (larger amplitude when the target was a rare light vs. a rare tone) was not significant and was not affected by stimulant medication. All these findings were comparable for the three ADHD subgroups, a result attesting to the generality of stimulant effects on information processing.

Arousal↗