The effect of distraction on acute schizophrenics' visual tracking.

To examine the nature of impaired smooth pursuit eye movement (SPEM) in schizophrenia, 16 hospitalized schizophrenics in the acute phase and 16 hospitalized nonpsychotic patients were studied. The experiment consisted of five 30-sec visual tracking phases: (i) base line (no distraction); (ii) auditory-visual distraction; (iii) middle base line; (iv) dichotic listening; and (v) final base line. Schizophrenics were characterized by significantly more velocity arrests throughout all phases of the experiment. Auditory-visual distraction did not impair either group's SPEM relative to base line performance. In contrast, dichotic listening significantly increased both groups' velocity arrests. This form of distraction also tended to produce greater impairment among schizophrenics. The failure of apparently intense auditory-visual distraction to significantly disrupt schizophrenics' SPEM suggests that inattentiveness alone does not account for schizophrenics' tracking impairment. This notion is supported by the finding that only the more intense distraction by dichotic listening produced a (trend toward) greater impairment in schizophrenics.

The late positive component of the evoked response in acute schizophrenics during a test of sustained attention.

To investigate the relationship between behavioral and cortical measures of impaired attention in schizophrenia, 17 hospitalized acute schizophrenics and 16 hospitalized nonpsychotic patients were studied. Event-related potentials (ERP) were obtained while subjects performed the Continuous Performance Test (CPT) under three conditions: First base line, Auditory-Visual Distraction, and Second base line. Schizophrenics made more errors of omission and commission and had longer reaction times. Analysis of the Late Positive Component (LPC) of the ERP revealed that both groups had an attenuated LPC during distraction and a larger LPC to the critical compared to the noncritical stimulus throughout all conditions. Schizophrenics had a smaller LPC and a smaller amplitude difference between the critical and noncritical stimulus than the nonpsychotics throughout all conditions.

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.

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.

Executive functioning deficits in attention-deficit/hyperactivity disorder are independent of oppositional defiant or reading disorder.

OBJECTIVE: To evaluate deficits of executive functions in children with attention-deficit/hyperactivity disorder (ADHD) classified by type (combined [CT] or predominantly inattentive [IT]) and comorbidity with oppositional defiant disorder (ODD) and reading disorder (RD). METHOD: The Wisconsin Card Sorting Test (WCST) and Tower of Hanoi (TOH) were administered to 28 community volunteers and 359 children (7.5-13.5 years old) divided into ADHD types, RD, and ODD. RESULTS: ADHD/CT children solved fewer puzzles and violated more rules on the TOH than ADHD/IT or non-ADHD subjects. On the WCST there were no differences between diagnostic samples in perseverativeness, but ADHD/CT patients made more nonperseverative errors than ADHD/IT children. ODD was associated with moderately better TOH performance and RD with excessive rule breaks. CONCLUSIONS: Executive functioning deficits were found for only ADHD/CT children and were independent of comorbidity with RD or ODD.

A further assessment of predictors of the child's behavior in dental treatment.

The child's disruptiveness during dental treatment was related modestly to his age as well as his state, trait, and dental anxiety. In three samples comprising 132 experienced and 49 inexperienced pedodontic patients, the child's behavior during treatment could not be predicted from any aspect of maternal anxiety -- trait, state, or dental. Previous conceptions of maternal influence on the child's dental anxiety should be re-evaluated.

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.

Clinical and cognitive effects of methylphenidate on children with attention deficit disorder as a function of aggression/oppositionality and age.

Children diagnosed with attention deficit disorder (ADD; n = 44), ADD plus aggression/oppositionality (ADD/O; n = 34), and as not meeting ADD criteria (NC; n = 29) received methylphenidate and placebo for 21 consecutive days each. Parents and teachers rated all groups improved under medication, but teachers reported less improvement for NC than for ADD/O children. Methylphenidate and chronological age had generally similar effects in a Sternberg task: greater accuracy and speed (especially for nontargets at low memory loads), larger P3b waves of event-related potentials, more pronounced slowing of P3b latency by memory load, and a greater trend of earlier peaks for targets than for nontargets. Both methylphenidate and maturation promoted more efficient strategies involving differentiated evaluation of targets and nontargets. These results were comparable among ADD groups.

Facial, autonomic, and subjective components of emotion: the facial feedback hypothesis versus externalizer-internalizer distinction.

Two different models have been advanced concerning the role of facial expression in the experience of emotion. The facial feedback hypothesis states that facial expressions regulate affective experience. This position has been supported by findings that experimentally induced changes in facial expressiveness produced corresponding changes in autonomic responses and self-reports of emotion. A second model posits that expressive behavior and autonomic responses are negatively related. Evidence supporting this view consists of correlational analyses showing that facially expressive people (externalizers) exhibit less autonomic arousal than do those who are not facially expressive (internalizers). In the present study, the facial feedback hypothesis and the externalizer-internalizer distinction were evaluated by manipulating facial expressiveness and measuring subsequent autonomic responses and self-reports of emotion. Results showed that higher levels of facial expressiveness were accompanied by higher levels of autonomic activity and subjective reports of affective experience. This relationship was obtained in comparisons among experimental conditions as well as correlational analyses within conditions.

Effects of warning-signal duration on the early and late components of the contingent negative variation.

Slow EEG potentials were recorded from three sites on the scalp (Fz, Cz and Pz) during a simple reaction time task in which the duration of the warning signal was either 0.5 or 2 sec. The duration of the foreperiod was held constant, and order of conditions was varied according to a latin square design. As predicted, the longer warning signal evoked increased amplitude of the early component of the contingent negative variation (CNV). These results confirm the interpretation of that wave as an orienting response. In contrast, the duration of the warning signal did not affect the second CNV component or reaction time latency. Additional dissociation between the two CNV components was evident in their distribution on the scalp. The early component was smallest at Pz, whereas the late component attained its lowest amplitude at Fz. Concurrently recorded palmar skin potentials exhibited different polarity and latency from the CNV.

Relationships between stimulus intensity and amplitude of visual and auditory event related potentials.

Event related potentials were recorded from subjects presented with separate trains of lights and tones of three intensity levels (75, 240 and 750 fl and 60, 77 and 95 dB respectively). The auditory P1-N1 and N1-P2 components increased linearly with loudness, whereas in visual evoked responses, these components were maximal at an intermediate brightness. There was no correlation between responses to the two modalities. The results are examined in relation to current theories of cortical stimulus processing.

Effects of lithium on evoked potentials and performance during sustained attention.

Two versions of the continuous performance test (CPT) differing in complexity were administered to 15 patients with bipolar affective disorder, manic type before and after treatment with lithium. Reaction time, performance accuracy, and the late positive component (LPC) of the event related potential evoked by the task were measured concurrently. Lithium treatment decreased errors of commission on both CPT tasks, although the difference was significant only for the simpler task. Reaction time was significantly increased by lithium treatment on the more difficult CPT task, LPC amplitude to the target stimulus on the difficult CPT was significantly increased by lithium. The data are interpreted as consistent with an attention-enhancing effect of lithium, coupled with a general reduction in the tendency to respond to stimuli.

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.

Methylphenidate does not modify the impact of response frequency or stimulus sequence on performance and event-related potentials of children with attention deficit hyperactivity disorder.

Twenty-six children with attention deficit/hyperactivity disorder (ADHD) participated in a double-blind trial consisting of 2 consecutive weeks each of placebo and methylphenidate (M = 26.92 mg/day = 0.78 mg/kg/day). As expected, stimulant therapy resulted in moderate weight loss, increased somatic complaints, and teacher and parent reports of reduced inattentiveness, aggression, and oppositionality. In both phases of the trial, patients were tested in a choice reaction time task assessing two aspects of the task that presumably affect response selection: response frequency (ratio of targets/nontargets = 25/75 vs. 50/50) and stimulus sequence (alternations vs. repetitions). Both manipulations yielded expected results on performance and event-related potentials (ERPs). Stimulant treatment increased accuracy and speed among younger children and curtailed variability of reaction time for the sample as a whole. However, methylphenidate did not affect ERPs. In combination, the results imply that the enhancement of performance by methylphenidate does not involve the demands of response selection examined in this study.

Methylphenidate slows reactions of children with attention deficit disorder during and after an error.

A Sternberg memory search task was administered under placebo and methylphenidate to 42 children with cross-situational attention deficit disorder (ADD), 31 children with cross-situational ADD plus oppositional features, and 25 patients with marginal ADD. Overall, stimulant medication enhanced accuracy and speed. In addition, patients reacted faster on correct responses not preceded by an error than on errors (especially false alarms) or on correct responses following an error. The slowness during error reactions may reflect decreased confidence or confusion during stimulus classification. This uncertainty may also lead subjects to respond with greater caution, hence more slowly, on correct responses following errors. Notably, methylphenidate increased the slowing of reactions on error trials as well as on correct reactions following an error. Stimulant medication may augment subjects' persistence when they are uncertain or confused, thereby heightening caution and promoting accuracy on succeeding trials. Consistent with previous reports of the generality of enhancement of performance by stimulant medication, the impact of methylphenidate was comparable for the three subtypes of ADD studied.

Learning-disordered children's evoked potentials during sustained attention.

Evoked potentials and performance of 19 learning-disordered (LD) and 19 normally achieving children were studied in two versions of the Continuous Performance Test (CPT). In both CPT procedures, LD children made more errors of omission and commission than did normal children. Evoked potential differences between groups were especially prominent in the more difficult BX version of the CPT. LD children displayed significantly smaller late positive components (LPC) of the evoked potential to critical stimuli in the task. There were no LPC differences between diagnostic groups for noncritical stimulus categories. The results suggest a deficit in behavioral and cortical indices of sustained attention among LD children.

Paired-associate learning in attention-deficit/hyperactivity disorder as a function of hyperactivity-impulsivity and oppositional defiant disorder.

A paired-associate learning (PAL) test was administered to 22 community volunteers without disruptive disorders and 197 children (7.5-13.5 years-old) presenting with the inattentive and combined subtypes of attention-deficit/hyperactivity disorder (ADHD) either in combination with or without oppositional defiant disorder (ODD). Participants were screened for learning disorders. In comparison to non-ADHD participants, children with ADHD achieved worse PAL and made errors rated as more acoustically and less semantically similar to the correct paired associates. These deficits were not related to hyperactivity-impulsivity or comorbid ODD. These results suggest that ADHD children are less competent at PAL and use less efficient learning strategies than their non-ADHD peers.

Cognitive event-related potentials in attention deficit disorder.

Cognitive event-related potentials (ERPs) have been used to aid in the interpretation of findings that children with Attention Deficit Disorder (ADD) make more errors and react more slowly than nondisabled controls in tests of sustained attention. Coincident with their abnormally poor performance, children with ADD have smaller late positive components of the ERP (especially a wave known as P3b) than their peers with psychiatric diagnoses. Notably, stimulant administration improves the performance of children with ADD and enlarges the amplitude of the late positive waves of their ERPs. These findings are interpreted as reflecting reduced capacity allocation, which, in turn, is increased by stimulant medications. Research on memory scanning suggests that children with ADD are deficient in energetic aspects of information processes and that their excessive slowness in reaction time tests involves stages following memory search and decision, that is, motor processes. The same factors seem to be involved in the amelioration of performance by stimulants, which speed up motor responses but do not affect the latency of P3b. Research on ERPs during selective attention also points to possible disturbances in this aspect of processing, but further research in this area is needed.

A comparison of unwed pregnant teenagers and nulligravid sexually active adolescents seeking contraception.

Unwed pregnant adolescents were contrasted with nulligravid teenagers seeking contraception. Pregnant subjects were less likely to employ or plan to use contraceptives. Gravid subjects more often described their boyfriends as happy about the pregnancy and expressed a desire for a pregnancy. Nulligravid youngsters described their parents as more disapproving of their premarital sexual activity. There is a need for counseling programs, including adolescents of both sexes, and aimed at the modification of attitudes toward contraception.