Reaction time distribution analysis of neuropsychological performance in an ADHD sample

Differences in reaction time (RT) variability have been documented between children with and without Attention Deficit Hyperactivity Disorder (ADHD). Most previous research has utilized estimates of normal distributions to examine variability. Using a nontraditional approach, the present study evaluated RT distributions on the Conners' Continuous Performance Test in children and adolescents from the Multimodal Treatment Study of ADHD sample compared to a matched sample of normal controls (n = 65 pairs). The ex-Gaussian curve was used to model RT and RT variability. Children with ADHD demonstrated faster RT associated with the normal portion of the curve and a greater proportion of abnormally slow responses associated with the exponential portion of the curve. These results contradict previous interpretation that children with ADHD have slower than normal responding and demonstrate why slower RT is found when estimates of variability assume normal Gaussian distributions. Further, results of this study suggest that the greater number of abnormally long RTs of children with ADHD reflect attentional lapses on some but not all trials.

Frontostriatal connectivity and its role in cognitive control in parent-child dyads with ADHD

OBJECTIVE

Many studies have linked the structure and function of frontostriatal circuitry to cognitive control deficits in attention deficit hyperactivity disorder (ADHD). Few studies have examined the role of white matter tracts between these structures or the extent to which white matter tract myelination and regularity correlate in family members with the disorder.

METHOD

Functional imaging maps from a go/nogo task were used to identify portions of the ventral prefrontal cortex and striatum involved in suppressing an inappropriate action (i.e., cognitive control) in 30 parent-child dyads (N=60), including 20 dyads (N=40) with ADHD and 10 dyads (N=20) without ADHD. An automated fiber-tracking algorithm was used to delineate white matter fibers adjacent to these functionally defined regions based on diffusion tensor images. Fractional anisotropy, an index of white matter tract myelination and regularity derived from diffusion tensor images, was calculated to characterize the associations between white matter tracts and function.

RESULTS

Fractional anisotropy in right prefrontal fiber tracts correlated with both functional activity in the inferior frontal gyrus and caudate nucleus and performance of a go/nogo task in parent-child dyads with ADHD, even after controlling for age. Prefrontal fiber tract measures were tightly associated between ADHD parents and their children.

CONCLUSIONS

Collectively, these findings support previous studies suggesting heritability of frontostriatal structures among individuals with ADHD and suggest disruption in frontostriatal white matter tracts as one possible pathway to the disorder.

ADHD- and medication-related brain activation effects in concordantly affected parent-child dyads with ADHD

BACKGROUND

Several studies have documented fronto-striatal dysfunction in children and adolescents with attention deficit/hyperactivity disorder (ADHD) using response inhibition tasks. Our objective was to examine functional brain abnormalities among youths and adults with ADHD and to examine the relations between these neurobiological abnormalities and response to stimulant medication.

METHOD

A group of concordantly diagnosed ADHD parent-child dyads was compared to a matched sample of normal parent-child dyads. In addition, ADHD dyads were administered double-blind methylphenidate and placebo in a counterbalanced fashion over two consecutive days of testing. Frontostriatal function was measured using functional magnetic resonance imaging (fMRI) during performance of a go/no-go task.

RESULTS

Youths and adults with ADHD showed attenuated activity in fronto-striatal regions. In addition, adults with ADHD appeared to activate non-fronto-striatal regions more than normals. A stimulant medication trial showed that among youths, stimulant medication increased activation in fronto-striatal and cerebellar regions. In adults with ADHD, increases in activation were observed in the striatum and cerebellum, but not in prefrontal regions.

CONCLUSIONS

This study extends findings of fronto-striatal dysfunction to adults with ADHD and highlights the importance of frontostriatal and frontocerebellar circuitry in this disorder, providing evidence of an endophenotype for examining the genetics of ADHD.

Assessing medication effects in the MTA study using neuropsychological outcomes

BACKGROUND

While studies have increasingly investigated deficits in reaction time (RT) and RT variability in children with attention deficit/hyperactivity disorder (ADHD), few studies have examined the effects of stimulant medication on these important neuropsychological outcome measures.

METHODS

316 children who participated in the Multimodal Treatment Study of Children with ADHD (MTA) completed the Conners' Continuous Performance Test (CPT) at the 24-month assessment point. Outcome measures included standard CPT outcomes (e.g., errors of commission, mean hit reaction time (RT)) and RT indicators derived from an Ex-Gaussian distributional model (i.e., mu, sigma, and tau).

RESULTS

Analyses revealed significant effects of medication across all neuropsychological outcome measures. Results on the Ex-Gaussian outcome measures revealed that stimulant medication slows RT and reduces RT variability.

CONCLUSIONS

This demonstrates the importance of including analytic strategies that can accurately model the actual distributional pattern, including the positive skew. Further, the results of the study relate to several theoretical models of ADHD.

Distraction as a determinant of processing speed

Processing speed is often described as a fundamental resource determining individual (e.g., I.Q.) and group (e.g., developmental) differences in cognition. However, most tests that measure speed present many items on a single page. Because many groups with slowed responding are also distractible, we compared younger and older adults on high-distraction (i.e., standard) versus low-distraction versions of two classic speed tasks. Reducing distraction improved the performance of older adults but had little or no effect on younger adults, suggesting that the ability to limit attentional access to task-relevant information can affect performance on tests designed to measure processing speed.

Assessment and prevention of head motion during imaging of patients with attention deficit hyperactivity disorder

The present study serves to detail the specific procedures for a mock scanner protocol, report on its use in the context of a multi-site study, and make suggestions for improving such protocols based on data acquired during study scanning. Specifically, a mock scanner compliance training protocol was used in a functional imaging study with a group of adolescents and adults with Attention Deficit Hyperactivity Disorder (ADHD) and a matched sample of healthy children and adults. Head motion was measured during mock and actual scanning. Participants across groups exhibited excess motion (>2 mm) on 43% of runs during the mock scanner. During actual scanning, excessive motion was limited to 10% of runs. There was a clear task-correlated head motion during a go/no-go task that occurred even after the compliance training: participants had a tendency to respond with increased head motion immediately after committing an error. This study illustrates the need to (1) report data attrition due to head motion, (2) assess task-related motion, and (3) consider mock scanner training in functional imaging protocols.

The effects of divided attention on encoding and retrieval processes: the resiliency of retrieval processes

We have recently cast doubt (Craik, Govoni, Naveh-Benjamin, & Anderson, 1996; Naveh-Benjamin, Craik, Guez, & Dori, 1998) on the view that encoding and retrieval processes in human memory are similar. Divided attention at encoding was shown to reduce memory performance significantly, whereas divided attention at retrieval affected memory performance only minimally. In this article we examined this asymmetry further by using more difficult retrieval tasks, which require substantial effort. In one experiment, subjects had to encode and retrieve lists of unfamiliar name-nouns combinations attached to people's photographs, and in the other, subjects had to encode words that were either strong or weak associates of the cues presented with them and then to retrieve those words with either intra- or extra-list cues. The results of both experiments showed that unlike division of attention at encoding, which reduces memory performance markedly, division of attention at retrieval has almost no effect on memory performance, but was accompanied by an increase in secondary-task cost. Such findings again illustrated the resiliency of retrieval processes to manipulations involving the withdrawal of attention. We contend that retrieval processes are obligatory or protected, but that they require attentional resources for their execution.

The role of children's ethnicity in the relationship between teacher ratings of attention-deficit/hyperactivity disorder and observed classroom behavior

Significant ethnic differences have been consistently documented on attention-deficit/hyperactivity disorder (ADHD) teacher rating scales. Whether these ethnic differences result from a teacher rating bias or reflect actual classroom behavior patterns is unknown. Ethnic differences between Caucasian and African American (AA) elementary schoolchildren on teacher ratings and codings of observed classroom behavior were examined with latent variables. In structural equation models, correlations between teacher ratings and observed classroom behavior suggested nonbiased teacher ratings of AA schoolchildren with diagnosed ADHD. Ethnic differences were documented for both teacher ratings of ADHD and classroom behavior. Differences in classroom behavior were attenuated when the behavior of an average child in the classroom was taken into account. Multiple explanations for this pattern of results are discussed.

Psoriasis and drugs: influence of tetracyclines on the course of psoriasis

Patients with psoriasis vulgaris (462) were studied by questionnaire to find the effect on psoriasis of drug therapy for intercurrent diseases or focal infections. Of 462 patients with psoriasis, in 76 (16.45%) the disease became more severe during drug therapy. Of these, 19 worsened after administration of tetracyclines, and in five psoriasis was precipitated after therapy with drugs of the tetracycline family. We suggest that tetracyclines should be avoided in patients with psoriasis and in healthy persons with a genetic predisposition (positive family history, human leukocyte antigens B13, B17, B27).

Achievement and maintenance of sustained response during the Treatment for Adolescents With Depression Study continuation and maintenance therapy

CONTEXT

The Treatment for Adolescents With Depression Study evaluated fluoxetine (FLX), cognitive behavioral therapy (CBT), and FLX/CBT combination (COMB) vs pill placebo in 439 adolescents with major depressive disorder. Treatment consisted of 3 stages: (1) acute (12 weeks), (2) continuation (6 weeks), and (3) maintenance (18 weeks).

OBJECTIVE

To examine rates of achieving and maintaining sustained response during continuation and maintenance treatments.

DESIGN

Randomized controlled trial. Response was determined by blinded independent evaluators.

SETTING

Thirteen US sites.

PATIENTS

Two hundred forty-two FLX, CBT, and COMB patients in their assigned treatment at the end of stage 1.

INTERVENTIONS

Stage 2 treatment varied based on stage 1 response. Stage 3 consisted of 3 CBT and/or pharmacotherapy sessions and, if applicable, continued medication.

MAIN OUTCOME MEASURES

Sustained response was defined as 2 consecutive Clinical Global Impression-Improvement ratings of 1 or 2 ("full response"). Patients achieving sustained response were classified on subsequent nonresponse status.

RESULTS

Among 95 patients (39.3%) who had not achieved sustained response by week 12 (29.1% COMB, 32.5% FLX, and 57.9% CBT), sustained response rates during stages 2 and 3 were 80.0% COMB, 61.5% FLX, and 77.3% CBT (difference not significant). Among the remaining 147 patients (60.7%) who achieved sustained response by week 12, CBT patients were more likely than FLX patients to maintain sustained response through week 36 (96.9% vs 74.1%; P = .007; 88.5% of COMB patients maintained sustained response through week 36). Total rates of sustained response by week 36 were 88.4% COMB, 82.5% FLX, and 75.0% CBT.

CONCLUSIONS

Most adolescents with depression who had not achieved sustained response during acute treatment did achieve that level of improvement during continuation and maintenance therapies. The possibility that CBT may help the subset of adolescents with depression who achieve early sustained response maintain their response warrants further investigation.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00006286.

Ethnic Differences in Attributions and Treatment Expectancies for Adolescent Depression

Studies suggest that ethnicity and socioeconomic factors may relate to differences in treatment expectancies and the attributions made for emotional or behavioral problems. We examined ethnic differences in (1) parents' attributions about the causes of adolescent behavioral and emotional problems and (2) treatment expectancies among 236 adolescent participants who enrolled in a 36-week randomized controlled trial for depression. Controlling for education and income, European American parents were more likely to endorse beliefs reflecting physical causes of depression than African American parents. There were no ethnic differences for beliefs reflecting external, familial, or community factors. Ethnic differences were observed in the treatment expectancies reported by parents, but not adolescents, with African American parents more likely than European Americans and Other minorities to endorse positive expectations for CBT. These findings may have implications for understanding discrepancies in mental health service use.

Cognitive measures of adolescent depression: unique or unitary constructs?

The factor structure of several self-report questionnaires assessing depression-relevant cognitions frequently employed in clinical research was examined in a sample of 390 adolescents (M age = 14.54; 216 girls; 74% Caucasian) with current major depressive disorder enrolled in the Treatment of Adolescents with Depression Study. A four-factor solution resulted, accounting for 65% of the total variance. The factors were labeled (a) Cognitive Distortions and Maladaptive Beliefs, (b) Cognitive Avoidance, (c) Positive Outlook, and (d) Solution-Focused Thinking. Internal consistencies for the factor-based composite scores were .83, .85, .84, and .82, respectively. Girls endorsed more negative cognitions than boys on three of the four factors. Maladaptive cognitions were positively related to severity of depression and predicted treatment response. Taken together, findings indicated that there are four distinct domains of cognitions that are present among adolescents with depression that are tapped by several widely used self-report measures of cognitions.

[Internal biliary fistulas--diagnostic and therapeutic problems]

BACKGROUND

Internal biliary fistula (IBF) is still a challenging condition. The preoperative diagnosis is established in less than 50% of cases. Treatment is based on individual approach but postoperative morbidity and mortality rates are high.

AIM

To study the experince of our clinic in the diagnosis and treatment of IBF's and to make a review of the literature.

MATERIAL AND METHODS

a retrospective analysis of the data of 7 patients with IBF (0,53% of all surgical interventions on the biliary system during a 4-years period). The preoperative diagnosis was correct in only 2 cases. All the 7 patients were treated surgically.

RESULTS

The early postoperative mortality and morbidity rates were 0% and 42,86% respectively. The data of literature are reviewed and discussed.

CONCLUSION

IBS is a rare condition affecting more often women above 65 yrs suffering of gallstones. There are no typival clinical and laboratory data but US, CT-scan, ERCP and MRI might be a 100% informative. Open surgery remains the basic method of treatment.

[Postoperative entero-cutaneus fistulas--a study of 24 cases]

AIM

To perform a retrospective study on the experience of the Clinic of General, Liver, Biliary and Pancreatic Surgery, Alexandrovska Hospital in the diagnosis and treatment of patients with acquired entero-cutaneus fistulas and to analyse the early postoperative results.

MATERIAL AND METHODS

We treated 24 patients with postoperative entero-cutaneous fistulas in the period Jan., 2000 - Aug., 2004. The male sex and the age above 50 were dominent. The primary disease was of oncological origin in 22 cases (91.66%). Anemia, hypoprotenemia and hypoalbuminemia were predisposing and risk factors in 19 cases (79.17%). Fistulography was routinely used for establishing the diagnosis. Surgical treatment was received by all the 6 patients (100%) with small bowel fistulas and by 15 from the 18 patients with large bowel fistulas (83.33%). EARLY POSTOPERATIVE RESULTS: The mortality rate was 4.54% (1 fatal outcome from 22 operated patients). The morbidity rate was 36,36% (8 cases) but none of the complications needed a reoperation.

CONCLUSIONS

1. The most frequent causal factor for entero-cutaneus fistulas in our material was an anastomotic leakige after bowel resection (95.83%); 2. The risk for such a coplication is higher in cancer patients with other predisposing pathological factors; 3. From the pahtological and clinical point of view the entero-cutaneus fistulas caused significant disturbances in base-alkaline and electrolyte balance, malnutrition and cahexia; 4. The clinical signs and the fistulography prooved to be reliable diagnostic methods; 5. The preoperative substitution and nutritional therapy had a significant benefit on the postoperative results, especially in cases of small bowel fistulas; 6. The open surgery was the main therapeutical method in the complex treatment of those patients.

[Modified method of Sugiura-Futagawa for surgical treatment in patients with portal hypertension and esophageal varices]

BACKGROUND

The esophageal transection and devascularization (Sugiura-Futagawa's operation) is the most frequently used ablative procedure in Japan for the treatment of patients with portal hypertension (PH) and esophageal varices (EV). Recently many authors, who are followers of this method, try to find an alternative one, aiming to shorten the skin-to-skin time and achieve better early and late results.

AIM

To study the postoperative results of our modification of the original Sugiura-Futagawa's method and to conclude whether it is good and reliable or not.

MATERIAL AND METHODS

From Jan. 1988 till Apr. 2001 we operated 25 patients with liver cirrhosis, PH and previous hemorrhage from EV, of whom 12 were male (48%) and 13--female (52%). Age of the patients--26-67 years. The ethiology of cirrhosis was alcoholic in 8 cases (32%) and post viral hepatitis--in 17 cases (68%). All our patients belonged to Child-Pugh's group A. The operative technique of our modification is described--transabdominal esophageal devascularisation, deconnection and reanastomosis.

RESULTS

The early postoperative mortality rate after our modification of the Sugiura-Futagawa's method was 12% (in 3 cases). Death cause--fulminant hepatic failure with hepato-renal syndrome (in all three cases). The mortality rate was also 12% but no one of the complications was life threatening or an indication for reoperation. The 5-year survival rate accounted 78%, recurrent esophageal bleeding--7.14% and late hepatal encephalopathy--also 7.14% of the followed patients.

DISCUSSION

The surgical treatment is of main importance for better survival in cases of PH and previously bled EV. A comparison between the results of other authors and our results is made.

CONCLUSION

The proposed by us transabdominal esophageal devascularisation, deconnection and reanastomosis as a modification of the Sugiura-Futagawa's procedure is easy fro the technical point of view and leads to good results.

[Acquierd entero-cutaneous fistulas--diagnostic and therapeutic approach]

The acquired entero-cutaneous fistulas are a current problem in the field of abdominal surgery. Most of them are postoperative--after an intestinal resection and/or anastomosis. Crohn's disease and coplicated colonic diverticulosis rank second as causal factors. The risk factors for the development of an entero-cutaneous fistula and for the poor prognosis at the same time are the next: (1) Most of the patients suffer of severe main and co-exhisting diseases; (2) The presence of previous laparotomies, radion and chemotherapy, significant disturbances in the base-acid and water-electrolyte balance; (3) The fistula itself worsens these disturbances and may doom to fail the substitutional and nutritional therapy. The diagnostics of a fistula, including its location is comparatively easy. The surgical treatment plays an important role in the therapeutic scheme, especially in cases of high-output fistulas of the small intestin. At the same time the adequate total parenteral nutrition and correction of the base-acid and water-electrolyte disbalance is also very important. Recently there are some new diagnostic methods and alternatives of the basic surgical procedures, some of them quite contraversial.

[Dyskeratosis congenita (Zinsser-Engman-Cole syndrome)]

We report on a 23-year-old white Cuban suffering from congenital dyskeratosis. In addition to the obligatory triad of poikilodermia, onychodystrophy, and leukoplakia, the patient showed congenital stenosis of the esophagus and extreme seborrhea of the scalp.

Depot sulfonamid associated linear IgA bullous dermatosis with erythema multiforme-like clinical features

A case of erythema multiforme-like reaction, following therapy with sulfadimethoxynum is reported in a 19-year-old male patient. Histological examination demonstrated a subepidermal bulla and direct immunofluorescence revealed linear deposition of IgA at the dermoepidermal junction. These observations illustrate that linear IgA bullous dermatosis can mimic the clinical features of erythema multiforme and suggest the possibility of drug-induced pathogenesis.

[Pachydermoperiostosis (Touraine-Solente-Golé syndrome)]

We report on a 38-year-old male patient suffering from pachydermoperiostosis (Touraine-Solente-Golé Syndrome), who underwent a cosmetic operation without success.

[Mesenteric-inferior-renal shunt--alternative of proximal and distal spleen-renal shunt for surgical treatment of portal hypertension]

Surgical operations are important for the prevention of recurrent bleeding and better survival rates in patients with portal hypertension and previous haemorrhage from esophageal varices, stopped by conservative treatment. Spleno-renal shunts are among the most frequently used procedures in these cases. Sometimes the proximal spleno-renal shutting operation of Linton or the distal one of Warren may be impossible from the technical point of view due to anomalies or varieties of the lienal vein. This makes it necessary to look for an alternative decision. This case report is about a 33-year old man indicated for surgical treatment because of portal hypertension, caused by prehepatic portal vein obstruction and esophageal varices with previous bleeding. Performing Linton's or Warren's procedure was not the proper decision. That's why we made a shunt between the inferior mesenteric vein and the left renal vein. The surgical technique and the postoperative results are described and discussed.