The role of neuropsychological assessment in adults with attention deficit/hyperactivity disorders

Attention-Deficit Hyperactivity Disorder (ADHD) is a neurodevelopmental disorder characterized by inattention, hyperactivity and/or impulsivity. While ADHD was initially recognized as a childhood syndrome, scientific evidence accumulated to indicate that a significant proportion of ADHD children continue to experience symptoms of ADHD in adulthood. Moreover, the question of ADHD diagnosis can arise in adult patients who were not diagnosed in childhood. Currently, the diagnosis of ADHD in adulthood is based on the revised criteria described for children. However, their application for adults may be difficult for many reasons including compensation and comorbid disorders. To date, no clinical, neuropsychological, biological or imaging marker is available for the diagnosis of ADHD. Considering that ADHD is based on a neuropsychological model, in this article we will examine the usefulness of neuropsychological testing in the diagnosis in adults. We will first present diagnostic criteria of ADHD and the limits of their application in adults. We will then detail the neuropsychological data available in adult ADHD and the French and international clinical recommendations for neuropsychological assessment. Finally, we will explore the predictive value of neuropsychological scores in the diagnosis of ADHD and discuss key methodological points and perspectives for clinical research.

Effect of stimulus type and pitch salience on pitch-sequence processing

Using a same-different discrimination task, it has been shown that discrimination performance for sequences of complex tones varying just detectably in pitch is less dependent on sequence length (1, 2, or 4 elements) when the tones contain resolved harmonics than when they do not [Cousineau, Demany, and Pessnitzer (2009). J. Acoust. Soc. Am. 126, 3179-3187]. This effect had been attributed to the activation of automatic frequency-shift detectors (FSDs) by the shifts in resolved harmonics. The present study provides evidence against this hypothesis by showing that the sequence-processing advantage found for complex tones with resolved harmonics is not found for pure tones or other sounds supposed to activate FSDs (narrow bands of noise and wide-band noises eliciting pitch sensations due to interaural phase shifts). The present results also indicate that for pitch sequences, processing performance is largely unrelated to pitch salience per se: for a fixed level of discriminability between sequence elements, sequences of elements with salient pitches are not necessarily better processed than sequences of elements with less salient pitches. An ideal-observer model for the same-different binary-sequence discrimination task is also developed in the present study. The model allows the computation of d' for this task using numerical methods.

Frequency tagging to track the neural processing of contrast in fast, continuous sound sequences

The human auditory system presents a remarkable ability to detect rapid changes in fast, continuous acoustic sequences, as best illustrated in speech and music. However, the neural processing of rapid auditory contrast remains largely unclear, probably due to the lack of methods to objectively dissociate the response components specifically related to the contrast from the other components in response to the sequence of fast continuous sounds. To overcome this issue, we tested a novel use of the frequency-tagging approach allowing contrast-specific neural responses to be tracked based on their expected frequencies. The EEG was recorded while participants listened to 40-s sequences of sounds presented at 8Hz. A tone or interaural time contrast was embedded every fifth sound (AAAAB), such that a response observed in the EEG at exactly 8 Hz/5 (1.6 Hz) or harmonics should be the signature of contrast processing by neural populations. Contrast-related responses were successfully identified, even in the case of very fine contrasts. Moreover, analysis of the time course of the responses revealed a stable amplitude over repetitions of the AAAAB patterns in the sequence, except for the response to perceptually salient contrasts that showed a buildup and decay across repetitions of the sounds. Overall, this new combination of frequency-tagging with an oddball design provides a valuable complement to the classic, transient, evoked potentials approach, especially in the context of rapid auditory information. Specifically, we provide objective evidence on the neural processing of contrast embedded in fast, continuous sound sequences.NEW & NOTEWORTHY Recent theories suggest that the basis of neurodevelopmental auditory disorders such as dyslexia might be an impaired processing of fast auditory changes, highlighting how the encoding of rapid acoustic information is critical for auditory communication. Here, we present a novel electrophysiological approach to capture in humans neural markers of contrasts in fast continuous tone sequences. Contrast-specific responses were successfully identified, even for very fine contrasts, providing direct insight on the encoding of rapid auditory information.

Impaired encoding of rapid pitch information underlies perception and memory deficits in congenital amusia

Recent theories suggest that the basis of neurodevelopmental auditory disorders such as dyslexia or specific language impairment might be a low-level sensory dysfunction. In the present study we test this hypothesis in congenital amusia, a neurodevelopmental disorder characterized by severe deficits in the processing of pitch-based material. We manipulated the temporal characteristics of auditory stimuli and investigated the influence of the time given to encode pitch information on participants' performance in discrimination and short-term memory. Our results show that amusics' performance in such tasks scales with the duration available to encode acoustic information. This suggests that in auditory neuro-developmental disorders, abnormalities in early steps of the auditory processing can underlie the high-level deficits (here musical disabilities). Observing that the slowing down of temporal dynamics improves amusics' pitch abilities allows considering this approach as a potential tool for remediation in developmental auditory disorders.

Congenital amusia: a cognitive disorder limited to resolved harmonics and with no peripheral basis

Pitch plays a fundamental role in audition, from speech and music perception to auditory scene analysis. Congenital amusia is a neurogenetic disorder that appears to affect primarily pitch and melody perception. Pitch is normally conveyed by the spectro-temporal fine structure of low harmonics, but some pitch information is available in the temporal envelope produced by the interactions of higher harmonics. Using 10 amusic subjects and 10 matched controls, we tested the hypothesis that amusics suffer exclusively from impaired processing of spectro-temporal fine structure. We also tested whether the inability of amusics to process acoustic temporal fine structure extends beyond pitch by measuring sensitivity to interaural time differences, which also rely on temporal fine structure. Further tests were carried out on basic intensity and spectral resolution. As expected, pitch perception based on spectro-temporal fine structure was impaired in amusics; however, no significant deficits were observed in amusics' ability to perceive the pitch conveyed via temporal-envelope cues. Sensitivity to interaural time differences was also not significantly different between the amusic and control groups, ruling out deficits in the peripheral coding of temporal fine structure. Finally, no significant differences in intensity or spectral resolution were found between the amusic and control groups. The results demonstrate a pitch-specific deficit in fine spectro-temporal information processing in amusia that seems unrelated to temporal or spectral coding in the auditory periphery. These results are consistent with the view that there are distinct mechanisms dedicated to processing resolved and unresolved harmonics in the general population, the former being altered in congenital amusia while the latter is spared.

What is a melody? On the relationship between pitch and brightness of timbre

Previous studies showed that the perceptual processing of sound sequences is more efficient when the sounds vary in pitch than when they vary in loudness. We show here that sequences of sounds varying in brightness of timbre are processed with the same efficiency as pitch sequences. The sounds used consisted of two simultaneous pure tones one octave apart, and the listeners’ task was to make same/different judgments on pairs of sequences varying in length (one, two, or four sounds). In one condition, brightness of timbre was varied within the sequences by changing the relative level of the two pure tones. In other conditions, pitch was varied by changing fundamental frequency, or loudness was varied by changing the overall level. In all conditions, only two possible sounds could be used in a given sequence, and these two sounds were equally discriminable. When sequence length increased from one to four, discrimination performance decreased substantially for loudness sequences, but to a smaller extent for brightness sequences and pitch sequences. In the latter two conditions, sequence length had a similar effect on performance. These results suggest that the processes dedicated to pitch and brightness analysis, when probed with a sequence-discrimination task, share unexpected similarities.

The basis of musical consonance as revealed by congenital amusia

Some combinations of musical notes sound pleasing and are termed "consonant," but others sound unpleasant and are termed "dissonant." The distinction between consonance and dissonance plays a central role in Western music, and its origins have posed one of the oldest and most debated problems in perception. In modern times, dissonance has been widely believed to be the product of "beating": interference between frequency components in the cochlea that has been believed to be more pronounced in dissonant than consonant sounds. However, harmonic frequency relations, a higher-order sound attribute closely related to pitch perception, has also been proposed to account for consonance. To tease apart theories of musical consonance, we tested sound preferences in individuals with congenital amusia, a neurogenetic disorder characterized by abnormal pitch perception. We assessed amusics' preferences for musical chords as well as for the isolated acoustic properties of beating and harmonicity. In contrast to control subjects, amusic listeners showed no preference for consonance, rating the pleasantness of consonant chords no higher than that of dissonant chords. Amusics also failed to exhibit the normally observed preference for harmonic over inharmonic tones, nor could they discriminate such tones from each other. Despite these abnormalities, amusics exhibited normal preferences and discrimination for stimuli with and without beating. This dissociation indicates that, contrary to classic theories, beating is unlikely to underlie consonance. Our results instead suggest the need to integrate harmonicity as a foundation of music preferences, and illustrate how amusia may be used to investigate normal auditory function.

The role of peripheral resolvability in pitch-sequence processing

The authors previously reported that same/different judgments on pitch sequences were more accurate for tones with resolved (low-rank) harmonics compared to unresolved (high-rank) harmonics, even when discriminability between tones was equated [Cousineau et al. (2009). J. Acoust. Soc. Am. 126, 3179-3187]. Here, peripheral resolvability, defined by the number of harmonics per cochlear filter, was contrasted with harmonic number. Tones were presented either diotically or dichotically. In the latter case, even and odd harmonics were presented to different ears, thus halving the number of harmonics per cochlear filter. Performance was better for dichotic than for diotic presentations. This indicates that peripheral resolvability is necessary and sufficient for efficient pitch-sequence processing.

What makes a melody: The perceptual singularity of pitch sequences

This study investigated the ability of normal-hearing listeners to process random sequences of tones varying in either pitch or loudness. Same/different judgments were collected for pairs of sequences with a variable length (up to eight elements) and built from only two different elements, which were 200-ms harmonic complex tones. The two possible elements of all sequences had a fixed level of discriminability, corresponding to a d(') value of about 2, irrespective of the auditory dimension (pitch or loudness) along which they differed. This made it possible to assess sequence processing per se, independent of the accuracy of sound encoding. Pitch sequences were found to be processed more effectively than loudness sequences. However, that was the case only when the sequence elements included low-rank harmonics, which could be at least partially resolved in the auditory periphery. The effect of roving and transposition was also investigated. These manipulations reduced overall performance, especially transposition, but an advantage for pitch sequences was still observed. These results suggest that automatic frequency-shift detectors, available for pitch sequences but not loudness sequences, participate in the effective encoding of melodies.

Medicaid managed care's impact on safety-net clinics in California

A growing percentage of Medicaid patients are receiving medical care within a managed care system. This policy change has raised concerns about whether safety-net providers can maintain their share of Medi-Cal (California Medicaid) patients. From 1995 to 1997 several of California's counties implemented mandatory Medi-Cal managed care. The majority of California's safety-net primary care clinics experienced a decline in the percentage of their patients insured by Medi-Cal. However, after the overall decline in the number of Medi-Cal beneficiaries was controlled for, the increased penetration of Medi-Cal managed care in a county was not independently associated with a decline in clinics' share of Medi-Cal patients. Despite this fact, it may become increasingly difficult for clinics to maintain their current level of services with declining Medi-Cal enrollment and other anticipated reforms in their funding.

[Support programs for employees.]

This article briefly traces the history of employees' help programs and describes their activities and the modalities of their organization. It illustrates the impact such programs have on the mental health of an entreprise and their employees.

Calcium oxalate crystal growth in normal urine: role of contraceptive hormones

Oral contraceptives inhibited the growth of calcium oxalate crystals in female urine, and the growth rate inhibition depended on the dose of ethinyl-oestradiol in the oral contraceptive agent. The results suggest that the crystallization kinetics of calcium oxalate in urine could be under the control of oestrogenic hormones by an unidentified mechanism.

Crystallisation of calcium oxalate dihydrate in normal urine in presence of sodium copper chlorophyllin

A method is described for the growth of calcium oxalate dihydrate in normal urine. Soluble chlorophyllin, at a concentration of 20 microgram/ml inhibited the crystallisation and the growth kinetics of the dihydrate crystals. The inhibitory capacity of chlorophyllin was compared with previous results. Data obtained suggest that the food and drug colourant chlorophyllin might be useful in the treatment of calcium oxalate stone disease.

Growth retardation of weddellite (calcium oxalate dihydrate) by sodium copper chlorophyllin

We studied the growth of calcium oxalate dihydrate crystals (weddellite) in simulated urine and its transformation into the more stable monohydrate (whewellite). Sodium copper chlorophyllin in a concentration of 100 microgram per ml inhibited the growth of calcium oxalate dihydrate crystals in simulated urine. The size distribution parameters of the dihydrate crystals in the presence and absence of chlorophyllin suggest that soluble chlorophyllin could be of clinical significance in calcium oxalate urolithiasis.

Effect of sodium copper chlorophyllin on the formation of calcium oxalate crystals in rat kidney

We induced the deposition of calcium oxalate crystals in rat kidney by intraperitoneal administration of 4-hydroxy-L-proline or sodium oxalate and studied the amounts and size distribution characteristics of the deposited crystals. Intravenous administration of sodium copper chlorophyllin inhibited the deposition and growth of calcium oxalate crystals induced by 4-hydroxy-L-proline or sodium oxalate. This finding may be of importance in calcium oxalate urolithiasis.

Suppression of lymphoblastoid cell line proliferation by antisera to HLA-DR and other HLA antigens

We have observed that certain antisera to HLA antigens suppress the in vitro proliferation of lymphoblastoid cell lines. An antiserum to HLA-B8 demonstrated suppressor activity associated with the presence of B8 antigen on the target LCLs; this activity was removed by absorption with platelets or with B8-positive LCLs. An antiserum to HLA-DRw7 suppressed proliferation of all six DRw7-positive LCLs and none of 12 DRw7-negative LCLs; this activity was removed by absorptions with three DRw7-positive LCLs, each representing a different HLA-D allele (i.e. Dw7, 10 and 11); it could not be removed by triple serial absorptions with platelets from multiple-donor pools. These experiments indicate that the suppressor activity of this serum is specifically associated with antibodies to DRw7. Our model of LCL growth suppression by HLA antisera is easily manipulated and provides a definitive tool for further characterizing HLA antigens and antisera in a complement-independent system.

Late sequelae of penetrating cardiac wounds

Physiological and psychological parameters of 20 survivors of penetrating wounds of the heart were examined 7 to 52 months after recovery. All survivors had cardiac complaints. The psychological parameters for hypochondriasis, compulsiveness, and internalization were much greater in the patients than in control subjects but were similar to those in victims of violent major abdominal trauma. Physiological abnormalities were present in 19, although no particular pattern or abnormality could be related with certainty to the type of wound, operative procedure, or postoperative course. One recovered and re-employed victim required late surgical repair of a traumatic ventricular septal defect and ventricular diverticulum. Although functional work capacity measured by stress testing was normal in 90 percent, only eight survivors resumed employment. Complete rehabilitation was impaired by a residual traumatic neurosis. Management goals for patients with penetrating cardiac wounds should be broadened to include prevention of psychological disabilities.