Search PubMed⌕ Search

Biomedical subjects

Martin Holtmann

Publications and source records attributed to Martin Holtmann.

17 recordsLinked to original sources
PubMed2006

Gestalt perception and local-global processing in high-functioning autism.

This study examined gestalt perception in high-functioning autism (HFA) and its relation to tasks indicative of local visual processing. Data on of gestalt perception, visual illusions (VI), hierarchical letters (HL), Block Design (BD) and the Embedded Figures Test (EFT) were collected in adult males with HFA, schizophrenia, depression and normative controls. Individuals with HFA processed gestalt stimuli less in accord with gestalt laws, particularly regarding the principle of similarity. Gestalt processing correlated positively with global processing of the HL. EFT and BD performance correlated negatively with VI susceptibility in HFA. All clinical groups succumbed less to VI than the normative sample. Results suggest decreased gestalt perception in HFA, being associated with a more general local visual processing bias.

Adult↗
PubMed2006

Rolandic spikes increase impulsivity in ADHD - a neuropsychological pilot study.

The present study was designed to examine the association of Rolandic spikes with the neuropsychological profile of children with ADHD. A total of 48 children (mean age 9.4 +/- 1.6 years, range 6.7-14.9 years; 16 ADHD children with Rolandic spikes, 16 ADHD children without epileptiform discharges and 16 healthy controls) matched for age, gender, and IQ were examined with a neuropsychological assessment battery focussing on attentional processing, cognitive efficiency, response inhibition, visuospatial and auditory-verbal short-term memory and language function (CPT-AX, Stroop, digit span, Complex Figure of Rey, Heidelberg Language Development Test). ADHD children with Rolandic spikes performed worse than ADHD children without epileptiform discharges and healthy controls in a variety of CPT and Stroop test measures. In particular, they made significantly more commission errors, reflecting impaired inhibition of an ongoing response. In addition, they had pronounced difficulties in the color word condition of the Stroop test and exhibited lower interference scores, indicating poorer interference control. Results of this pilot study suggest that in some ADHD children Rolandic spikes or an associated dysfunction aggravate the course of ADHD and predispose to increased impulsivity, evidenced in deficient inhibition of an ongoing response, and decreased interference control.

Adolescent↗
PubMed2006

[Do subclinical epileptiform discharges really affect short-term memory in children?].

OBJECTIVE: Deficits in concentration, specific developmental disorders, and behaviour problems often impair the educational abilities of children and adolescents with epilepsy, even if the subjects are seizure-free. The impact of subclinical epileptiform discharges that persist despite adequate antiepileptic treatment is not yet understood. Some studies suggest that these lead to simultaneous transitory cognitive impairment, thereby affecting short-term memory functions. This study examines the impact of subclinical discharges on memory functions. METHOD: 40 seizure-free children (10.3 +/- 3.5 years) with subclinical epileptiform discharges were examined by means of computerized EEG-coupled tests focussing on visuo-spatial and verbal short-term memory, in order to assess the temporal relation between discharges and test performance. RESULTS: No significant differences in cognitive performance were detected in phases with and without epileptiform discharges; neither discharges > 1.5 sec, nor multiple discharges within a test impaired performance. Moreover, performance was independent of the localisation of discharges and of the time of their occurrence during the test. CONCLUSIONS: The present study showed no association between subclinical epileptiform discharges and error rates as indicators of transient cognitive impairment in visuo-spatial and verbal short-term memory. Hence, other mechanisms have to be taken into account to explain the known cognitive deficits in patients with epilepsy.

Adolescent↗
PubMed2006

[Methylphenidate-induced cytogenetic alterations?].

OBJECTIVES: Due to concerns that methylphenidate (MPH) might induce cytogenetic alterations in children, treatment with this drug is a controversial issue. The controversy arose following a report by El-Zein et al. (2005) of increased chromosomal aberrations, sister chromatid exchanges, and micronuclei in twelve children after three months of MPH treatment. METHODS: The study by El-Zein is discussed with regard to current cytogenetic standards and earlier studies on the mutagenicity, clastogenicity, and carcinogenicity of MPH are reviewed. RESULTS: Conclusions from the El-Zein study are limited due to methodological shortcomings. Results of animal studies on the mutagenicity and clastogenicity of MPH are inconsistent. While there was no indication of mutagenic effects in bacteria or mammalian cells, MPH might have some potential to induce clastogenic damage in mammalian cells. There was no evidence of carcinogenic activity in rats, while in mice the occurrence of hepatic neoplasms increased. In an epidemiological study, the incidence of cancers following MPH treatment was lower than had been expected. CONCLUSIONS: Given the ambiguous findings of genetic toxicology studies in animals, the paucity of long-term toxicology data on MPH in humans is disquieting. Although it seems premature to conclude that MPH entails a mutagenic risk, the concern raised by El-Zein et al. warrants profound clarification.

Adolescent↗
PubMed2006

Electroencephalographic biofeedback for the treatment of attention-deficit hyperactivity disorder in childhood and adolescence.

Considerable scientific effort has been directed at developing effective treatments for attention-deficit hyperactivity disorder (ADHD). Among alternative treatment approaches, electroencephalographic (EEG) biofeedback has gained promising empirical support in recent years. Short-term effects were shown to be comparable to those of stimulant medication at the behavioral and neuropsychological level, leading to significant decreases of inattention, hyperactivity and impulsivity. In addition, EEG biofeedback results in concomitant improvement of neurophysiological patterns. EEG biofeedback may already be used within a multimodal setting, providing affected children and adolescents with a means of learning to counterbalance their ADHD symptoms without side effects. However, there is still a strong need for more empirically and methodologically sound evaluation studies.

Adolescent↗
PubMed2006

Role of electroencephalography in attention-deficit hyperactivity disorder.

Attention-deficit hyperactivity disorder (ADHD) is characterized by symptoms of inattention, hyperactivity and impulsivity, and affects 3-5% of school-aged children. Recommendations regarding the relative importance of electroencephalography (EEG) in ADHD are ambiguous. Most guidelines for ADHD diagnostics only recommend an EEG in cases with clinical suggestion of seizure disorders or degenerative conditions and not for routine use. Although in most cases of ADHD, an EEG is indeed unnecessary, without a routine EEG, some children with absences or rolandic spikes will not be identified and, therefore, will not be treated correctly. The EEGs of children with ADHD demonstrated increased theta activity and fewer alpha waves compared with controls. Research on event-related potentials is helpful in identifying underlying attentional deficits in ADHD. Future studies that combine EEG analysis with functional magnetic resonance imaging data, positron emission tomography studies or genetic research will help to improve our knowledge about the pathophysiology of ADHD and perhaps lead to a better, more individual treatment in well defined subgroups.

Attention Deficit Disorder with Hyperactivity↗
PubMed2006

[Familial patterns in disorders of attention and impulse control].

Attention deficit hyperactivity disorder (ADHD) persists into adulthood in about 30 to 50% of cases. Symptoms of ADHD in parents might affect effective therapeutic approaches in children. The objective of this study was to investigate (1) the retrospective rate of ADHD in biological parents of children with a diagnosis of ADHD, (2) the relation between retrospective ADHD symptomatology and current attention problems and impulsivity in parents, (3) whether the degree of ADHD severity and comorbidty in ADHD children depends on parental ADHD symptoms. The Wender-Utah-Rating Scale for the retrospective assessment of childhood attention deficit hyperactivity disorder was administered to the biological parents of n = 68 ADHD patients and detected high rates of ADHD in fathers (31%) and mothers (25%) of patients with ADHD. Retrospectively assessed symptoms in parents correlated significantly with current symptoms of attention problems (ADD-Brown scales) and impulsivity (17). In children, the highest degree of ADHD symptoms and comorbidty was found in children with both parents suffering from ADHD in childhood compared to those with only one or none affected parent.

Adult↗
PubMed2004

[Neurofeedback for the treatment of attention-deficit/hyperactivity disorder (ADHD) in childhood and adolescence].

INTRODUCTION: A variety of non-pharmacological treatments for ADHD have failed to prove their effectiveness. The basis of evidence for neurofeedback (or EEG-biofeedback) has improved recently. Neurofeedback is aiming at an improvement of ADHD core-symptoms via the voluntary modification of abnormal neurophysiologic parameters, e.g. EEG-frequency spectrum and event-related potentials. METHODS: Our review presents an overview of the current research on neurofeedback for the treatment of ADHD. RESULTS: In three controlled studies short-term effects of feedback matched those of stimulant treatment. Neurofeedback lead to significant improvement of attention, impulsivity and hyperactivity, without adversive side effects. Additionally, there was a persistent amelioration of EEG parameters, while stimulants did not lead to a comparable normalization. Results on the stability of feedback effects are encouraging but are based on small numbers of patients. CONCLUSION: Neurofeedback is a promising approach for the treatment of children with ADHD. However, there is a demand for further controlled studies using standardized diagnostic criteria, sufficient sample sizes and appropriate measures and follow-up.

Adolescent↗
PubMed2003

Increased frequency of rolandic spikes in ADHD children.

PURPOSE: Some children with rolandic epilepsy have associated neuropsychiatric deficits resembling symptoms of attention deficit-hyperactivity disorder (ADHD), the most common neurobehavioral disorder of childhood. The clinical overlap between both syndromes has received relatively little attention. The study examines the frequency of rolandic spikes in nonepileptic children with ADHD and compares it with a historic control group of 3,726 normal school-aged children. ADHD patients with and without discharges are compared regarding age at admission, sex, global functioning, and distribution of ADHD subtypes. METHODS: The EEGs of 483 ADHD outpatients between 2 and 16 years meeting diagnostic criteria for ADHD according to Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) were evaluated prospectively. If rolandic spikes were present, separate sleep EEGs were performed to exclude a bioelectrical status epilepticus during slow-wave sleep. RESULTS: Rolandic spikes were detected in the EEGs of 27 children (5.6%; 22 boys and five girls). Seizure rate during follow-up tended to be larger in children with rolandic spikes. No significant differences were found between ADHD patients with and without spikes regarding sex and global functioning. ADHD children with rolandic spikes came to our attention significantly earlier than did children without discharges and tended to exhibit more hyperactive-impulsive symptoms, evidenced in a larger proportion of the diagnosis of ADHD combined type than ADHD inattentive type. CONCLUSIONS: The frequency of rolandic spikes in children with ADHD is significantly higher than expected from epidemiologic studies. The question arises how ADHD symptoms are related to rolandic spikes in this ADHD subgroup. Possibly rolandic discharges or underlying, not fully understood mechanisms of epileptogenesis decrease the vulnerability threshold, advance the onset, or aggravate the course of ADHD.

Action Potentials↗
PubMed2003

Methylene blue-aided chromoendoscopy for the detection of intraepithelial neoplasia and colon cancer in ulcerative colitis.

BACKGROUND & AIMS: Timely diagnosis of intraepithelial neoplasias (IN) and colitis-associated colon carcinomas (CRC) is crucially important for the treatment of ulcerative colitis (UC). We performed a randomized, controlled trial to test whether chromoendoscopy (CE) might facilitate early detection of IN and CRC in UC. METHODS: A total of 263 patients with long-standing UC (>or=8 years) were screened for potential inclusion in the study, 165 of whom were randomized at a 1:1 ratio to undergo conventional colonoscopy or colonoscopy with CE using 0.1% methylene blue. Five mucosal biopsy specimens were taken every 10 cm between the rectum and cecum. Circumscript lesions in the colon were evaluated according to a modified pit pattern classification. RESULTS: In the CE group, there was a significantly better correlation between the endoscopic assessment of degree (P = 0.0002) and extent (89% vs. 52%; P < 0.0001) of colonic inflammation and the histopathologic findings compared with the conventional colonoscopy group. More targeted biopsies were possible, and significantly more IN were detected in the CE group (32 vs. 10; P = 0.003). Using the modified pit pattern classification, both the sensitivity and specificity for differentiation between non-neoplastic and neoplastic lesions were 93%. CONCLUSIONS: Based on our prospective randomized trial, CE permits more accurate diagnosis of the extent and severity of the inflammatory activity in UC compared with conventional colonoscopy. In addition, CE with methylene blue is a novel tool for the early detection of IN and CRC in patients with UC. These findings have important implications for medical and surgical interventions.

Adult↗
PubMed2003

Risperidone-associated ejaculatory and urinary dysfunction in male adolescents.

We report two male adolescents who developed partial or complete retrograde ejaculation during risperidone treatment. Additionally, one patient complained of bladder outflow obstruction, and the other reported a reduced ejaculatory volume and decreased viscosity of semen. On rechallenge with risperidone, patient A showed a prompt recurrence of the ejaculatory dysfunction. The side effects were highly disturbing and led to reduced treatment compliance in both patients. The impact of risperidone, a strong alpha(1)-receptor antagonist, on the adrenergic system might induce retrograde ejaculation by altering the sympathetic tonus, allowing semen to pass retrogradely into the bladder during ejaculation. The reduced ejaculatory volume may be caused by risperidone-induced hyperprolactinemia. Clinicians should regularly inquire about sexual dysfunction and symptoms suggestive of hyperprolactinemia before starting risperidone treatment and regularly thereafter.

Adolescent↗
PubMed2003

CD28-dependent Rac1 activation is the molecular target of azathioprine in primary human CD4+ T lymphocytes.

Azathioprine and its metabolite 6-mercaptopurine (6-MP) are immunosuppressive drugs that are used in organ transplantation and autoimmune and chronic inflammatory diseases such as Crohn disease. However, their molecular mechanism of action is unknown. In the present study, we have identified a unique and unexpected role for azathioprine and its metabolites in the control of T cell apoptosis by modulation of Rac1 activation upon CD28 costimulation. We found that azathioprine and its metabolites induced apoptosis of T cells from patients with Crohn disease and control patients. Apoptosis induction required costimulation with CD28 and was mediated by specific blockade of Rac1 activation through binding of azathioprine-generated 6-thioguanine triphosphate (6-Thio-GTP) to Rac1 instead of GTP. The activation of Rac1 target genes such as mitogen-activated protein kinase kinase (MEK), NF-kappaB, and bcl-x(L) was suppressed by azathioprine, leading to a mitochondrial pathway of apoptosis. Azathioprine thus converts a costimulatory signal into an apoptotic signal by modulating Rac1 activity. These findings explain the immunosuppressive effects of azathioprine and suggest that 6-Thio-GTP derivates may be useful as potent immunosuppressive agents in autoimmune diseases and organ transplantation.

Adult↗
PubMedDate not supplied

[Improving medical students' interactive competence].

We report a new curriculum for improving medical students' interactive competence. The curriculum is based on the method of "psychotherapeutic plan analysis" by F. Caspar in combination with elements of systemic supervision and problem-based learning. For evaluation, participants (fifth year medical students, n = 50) were asked to fill in a questionnaire adapted to the contents of the course. Comparison was made possible by a control group (n = 72) teached in a traditional manner. Evaluation showed significant improvement of the students' self awareness, perception of their patients and sensibility for patients' needs. The students expanded their capability to reflect own actions and to work in teams. Initially expressed anxiety concerning contact with patients was reduced significantly during the course. In three and twelve months follow-ups, students still considered their personal achievement to be significantly high. Participants of the curriculum rated their courses higher with regard to didactic issues, improvement of interactive competences and personal relevance, while control courses were seen to be more relevant to prepare for exams.

Adult↗