Examination of Spatial Working Memory Performance in Children and Adolescents with Attention Deficit Hyperactivity Disorder, Combined Type (ADHD-CT) and Anxiety

Spatial working memory (SWM) is known to be impaired in children with ADHD-CT, whether anxiety is present or not. Yet, it remains unclear whether anxiety disorders add to the SWM impairments evident in ADHD-CT and whether these findings extend into adolescents with ADHD-CT and anxiety. Further, it is not yet known whether children and adolescents with carefully defined anxiety disorders alone, demonstrate SWM deficits. This study explored the association of SWM and its strategy and spatial span components in carefully defined children and adolescents (age 6–16 years) with ADHD-CT alone (N?=?163; 14 % female), ADHD-CT and anxiety (N?=?243; 23 % female), anxiety disorders alone (N?=?69; 25 % female) compared to age- and gender-matched healthy control participants (N?=?116; 19 % female). The relationship between SWM and its strategy and span components and core ADHD-CT symptoms and anxiety symptoms were also examined. There was no evidence of an additive effect of ADHD and anxiety on SWM, strategy and spatial span deficits. But, anxiety disorders alone were associated with impaired SWM and span performance compared to healthy control participants. In contrast, strategy did not differ between children and adolescents with anxiety disorders alone and healthy control participants, suggesting that with anxiety span is the most affected component. Further, these findings were age-independent. This study concurs with and extends current influential models about the cognitive effects of anxiety on performance in the setting of ADHD-CT. Clinical implications and future research directions are discussed.     

Associative priming effects with visible, transposed-letter nonwords: JUGDE facilitates COURT

Associative priming effects can be obtained with masked nonword primes or with masked pseudohomophone primes (e.g., judpe?CCOURT, tode?CFROG), but not with visible primes. The usual explanation is that when the prime is visible, these stimuli no longer activate the semantic representations of their base words. Given the important role of transposed-letter stimuli (e.g., jugde) in visual word recognition, here we examined whether or not an associative priming effect could be obtained with visible transposed-letter nonword primes (e.g., jugde?CCOURT) in a series of lexical decision experiments. Results showed a sizable associative priming effect with visible transposed-letter nonword primes (i.e., jugde?CCOURT faster than neevr?CCOURT) in Experiments 1?C3 that was close to that with word primes. In contrast, we failed to find a parallel effect with replacement-letter nonword primes (Experiment 2). These findings pose some constraints to models of visual word recognition.     

Underlying processes in the poor response inhibition of children with Attention-Deficit/Hyperactivity Disorder

This study evaluated the effects of reward, punishment, and reward + punishment on the impulsive responses of ADHD children. The impulsive responses of ADHD and normal control boys (30 per group) were compared during performance of a go/no-go task, administered under reward-only, punishment-only, and reward + punishment conditions. When differences in aggression, anxiety, and IQ between these groups were controlled for, results indicated that the impulsivity levels of the ADHD group were higher than the control group in all three reinforcement conditions. Also, the ADHD group was more impulsive in the reward + punishment condition, compared to the reward-only and punishment-only conditions, and there was no difference between the reward-only and punishment-only conditions. The control groups showed no difference across the three reinforcement conditions. These findings raise the possibility that the poor response inhibition of ADHD children may be related to both a generalized inhibitory deficit and a response modulation deficit.     

The filled-duration illusion: The function of temporal and nontemporal set

Studies of the perception of time have demonstrated that large visual stimuli presented for the same duration as small stimuli will appear to have been presented longer. Two theoretical approaches have been offered to explain this effect. Both have emphasized the absolute amount of information in the stimulus. Thus, both would predict the effect when size is varied between sessions. The present study found no effect of size when size was held constant within sessions, but a substantial effect resulted when size was varied within sessions. Also examined was the range of stimulus durations used within a session. In one condition, patterns of various sizes were presented at 15, 30, or 45 msec, while in a second condition, the same patterns were presented to a different group of subjects at 15, 85, or 155 msec. The size effect was significantly reduced when longer time intervals were presented. A third group of subjects was shown patterns at even longer times but with a reduced range (155, 170, and 185 msec). Here the size effect was of equal magnitude to that of the 15-msec interval condition. The implications of these results are that current theoretical explanations of the filled-duration illusion rely on incorrect assumptions.     

Reference frames in mental rotation

Four experiments are reported that investigate whether images or reference frames are transformed during a mental rotation task. In all experiments a display of four identical letters (P1) was presented at either +90 degrees or -90 degrees from upright, and subjects had to decide whether the letters were normal or mirror-image reflections. A single letter (P2) was then presented 100 ms later in a variable orientation with the same task instructions. Reaction times to P2 were assessed to determine whether an image of P2 was rotated to upright or whether an internal reference frame was rotated into congruence with P2 from the orientation of P1. The results as a whole suggest that transformations of P2 can be initiated either relative to upright or relative to the orientation of P1. They further indicate that the probability of using each reference orientation can be changed by procedural variations. The findings are most parsimoniously interpreted as suggesting that mental rotation involves the transformation of reference frames rather than the transformation of template-like representations.     

The Factor Structure of Anxiety and Depressive Disorders in a Sample of Clinic-Referred Adolescents

The current study used confirmatory factor analysis (CFA) to examine the factor structure of anxiety and depressive disorders in a sample of clinic-referred adolescents, aged between 12 and 18 years, for diagnoses based on parent (N?=?655; male?=?441) and adolescent (N?=?626; male?=?417) interviews. Three models were examined: a 1-factor model, with all anxiety and depressive disorders in a single factor; a DSM-based 2-factor model, with anxiety disorders in one factor, and depressive disorders in another factor; and an alternate 2-factor model, with fear related anxiety disorders in one factor, and other anxiety and depressive disorders in another factor. The findings indicated support for all three models. Also, ADHD and ODD/CD were associated with only the shared variances between the latent factors in the 2-factor models, and not their unique variance. The implications of the findings for taxonomy, comorbidity, and clinical practice are discussed.     

Attention and probabilistic sequence learning

Limitations of using fixed sequences of events in studies of learning in the sequential reaction-time task led us to develop a probabilistic version of the task. When sequences occur probabilistically, transitions usually follow a sequence, but with some small probability, events occur out of sequence. This variation on the paradigm provides new evidence associated with manipulations of attentional load. Most notably, single-task learning leads to particularly high error rates on improbable transitions, suggesting anticipation of the sequence. Dual-task learning shows sensitivity to the sequence (by reaction-time differences to probable and improbable transitions), but without inflated errors on improbable transitions. Sensitivity to the sequence and anticipatory errors disappeared when participants transferred from single-task learning to dual-task conditions, suggesting that what is learned with single-task practice cannot be applied under conditions of limited attention. When learners transferred from dual- to single-task conditions, sensitivity of RT to the sequence increased but anticipation errors remained the same, suggesting that attentional load limits performance, but not learning. Qualitative differences in performance result from variations in attentional resources, which may reflect different learning processes. Received: 17 February 1997 / Accepted: 5 January 1998     

Relationships between musical structure and psychophysiological measures of emotion

Psychophysiological studies with music have not examined what exactly in the music might be responsible for the observed physiological phenomena. The authors explored the relationships between 11 structural features of 16 musical excerpts and both self-reports of felt pleasantness and arousal and different physiological measures (respiration, skin conductance, heart rate). Overall, the relationships between musical features and experienced emotions corresponded well with those known between musical structure and perceived emotions. This suggests that the internal structure of the music played a primary role in the induction of the emotions in comparison to extramusical factors. Mode, harmonic complexity, and rhythmic articulation best differentiated between negative and positive valence, whereas tempo, accentuation, and rhythmic articulation best discriminated high arousal from low arousal. Tempo, accentuation, and rhythmic articulation were the features that most strongly correlated with physiological measures. Music that induced faster breathing and higher minute ventilation, skin conductance, and heart rate was fast, accentuated, and staccato. This finding corroborates the contention that rhythmic aspects are the major determinants of physiological responses to music.