Publications

OBJECTIVES: Gray and white matter volume deficits have been reported in a number of studies of children with attention-deficit/hyperactivity disorder (ADHD); however, there is a paucity of structural magnetic resonance imaging (MRI) studies of adults with ADHD. This structural MRI study used an a priori region of interest approach. METHODS: Twenty-four adults with DSM-IV ADHD and 18 healthy controls comparable on age, socioeconomic status, sex, handedness, education, IQ, and achievement test performance had an MRI on a 1.5T Siemens scanner. Cortical and sub-cortical gray and white matter were segmented. Image parcellation divided the neocortex into 48 gyral-based units per hemisphere. Based on a priori hypotheses we focused on prefrontal, anterior cingulate cortex (ACC) and overall gray matter volumes. General linear analyses of the volumes of brain regions, adjusting for age, sex, and total cerebral volumes, were used to compare groups. RESULTS: Relative to controls, ADHD adults had significantly smaller overall cortical gray matter, prefrontal and ACC volumes. CONCLUSIONS: Adults with ADHD have volume differences in brain regions in areas involved in attention and executive control. These data, largely consistent with studies of children, support the idea that adults with ADHD have a valid disorder with persistent biological features.

Three of 2000 diagnostic hysteroscopies revealed residual fetal bony fragments in women with abnormal uterine bleeding. Removal of bony fragments by hysteroscopy is associated with therapeutic success.

In vivo MRI-derived measurements of human cerebral cortex thickness are providing novel insights into normal and abnormal neuroanatomy, but little is known about their reliability. We investigated how the reliability of cortical thickness measurements is affected by MRI instrument-related factors, including scanner field strength, manufacturer, upgrade and pulse sequence. Several data processing factors were also studied. Two test-retest data sets were analyzed: 1) 15 healthy older subjects scanned four times at 2-week intervals on three scanners; 2) 5 subjects scanned before and after a major scanner upgrade. Within-scanner variability of global cortical thickness measurements was

In this article we address analytic challenges inherent in brain volumetrics (i.e., the study of volumes of brains and brain regions). It has sometimes been assumed in the literature that deviations in regional brain size in clinical samples are directly related to maldevelopment or pathogenesis. However, this assumption may be incorrect; such volume differences may, instead, be wholly or partly attributable to individual differences in overall dimension (e.g., for head, brain, or body size). What quantitative approaches can be used to take these factors into account? Here, we provide a review of volumetric and nonvolumetric adjustment factors. We consider three examples of common statistical methods by which one can adjust for the effects of body, head, or brain size on regional volumetric measures: the analysis of covariance, the proportion, and the residual approaches. While the nature of the adjustment will help dictate which method is most appropriate, the choice is context sensitive, guided by numerous considerations-chiefly the experimental hypotheses, but other factors as well (including characteristic features of the disorder and sample size). These issues come into play in logically framing the assessment of putative abnormalities in regional brain volumes.

Surfactants form association complexes with cyclodextrins. In the present investigation we have used NMR-diffusometry and electrical conductivity to follow the interactions which take place between beta-cyclodextrin and a bolaform surfactant: dodecane 1,12-bis(trimethylammonium bromide). Both (1)H NMR self-diffusion and conductometry data indicate the formation of a 1:1 inclusion complex. Assuming this stoichiometry, it was possible to calculate the association constant; from the analysis of the self-diffusion coefficients of free beta-cyclodextrin and the bolaform surfactant an association constant K=3x10(3)M(-1) was obtained while the analysis of conductivity data gave a comparable value of K=2.5x10(3)M(-1).

The aim of this study was to determine the role of regional cortical thickness in recall of verbal material over an extended time period. MRI scans of healthy adults of varying ages were obtained. Two scans were averaged per person to achieve high spatial resolution, and a semi-automated method for continuous measurement of thickness across the entire cortical mantle was employed. Verbal memory tests assessing recall after 5 min, 30 min, and a mean interval of 83 days were administered. A general linear model (GLM) of the effects of thickness at each vertex on the different memory indices was computed, controlling for gender, age, IQ, and intracranial volume. These analyses were repeated with hippocampal volume as an additional variable to be controlled for, to assess to which extent effects of cortical thickness were independent of hippocampal size. Minute effects of cortical thickness were observed with regard to shorter time intervals (5 and 30 min). However, even when controlling for the effects of hippocampal volume, higher recall across months was associated with thicker cortex of distinct areas including parts of the gyrus rectus, the middle frontal gyrus, the parieto-occipital sulcus and the lingual gyrus of both hemispheres. In addition, hemisphere-specific associations were found in parts of the right temporal and parietal lobe as well as parts of the left precuneus. This supports a unique and critical role of the thickness of distinct cortical areas in recall after months, more than after minutes.

OBJECTIVE: An important procedure in diagnosing stress-related disorders caused by dysfunction in the interaction of the heart with breathing, i.e., respiratory sinus arrhythmia (RSA), is to analyse the breathing first and then the heart rate. Analysing these measurements is a time-consuming task for the diagnosing clinician. A decision-support system in this area would reduce the analysis task of the clinician and enable him/her to give more attention to the patient. We have created a decision-support system which contains a signal classifier and a pattern identifier. The system performs an analysis of the physiological time series concerned which would otherwise be performed manually by the clinician. METHODS: The signal-classifier, HR3Modul, classifies heart-rate patterns by analysing both cardio- and pulmonary signals, i.e., physiological time series. HR3Modul uses case-based reasoning (CBR), using a wavelet-based method for retrieving features from the signals. The system searches for familiar shapes in the signals by comparing them with shapes already stored. We have applied a best fit scheme for handling signals of different lengths, as the length of a breath is highly dynamic. We also apply automatic weighting to the features to obtain a more autonomous system. The classified heart signals indicate if a patient may be suffering from a stress-related disorder and the nature of the disorder. These classified signals are thereafter sent to the second subsystem, the pattern-identifier. The pattern-identifier analyses the classified signals and searches for familiar patterns by identifying sequences in the classified signals. The identified sequences give clinicians a more complete analysis of the measurements, providing them with a better basis for diagnosis. RESULTS AND CONCLUSION: We have shown that a case-based classifier with a wavelet feature extractor and automatic weighting is a viable option for building a decision-support system for the psychophysiological domain, as it is at par, or even outperforms other retrieval techniques and is less complex.

The effect of some amphipilic diblock-copolymers and comb-polymers on a balanced Winsor III microemulsion system is investigated with the quaternary system n-octyl-β-d-glucoside/1-octanol/n-octane/D2O as basis system. The diblock-copolymers are polyethyleneoxide-co-polydodecenoxide (PEO x PEDODO y ) and polyethyleneoxide-co-polybutyleneoxide (PEO x PEBU y ), constituted of a straight chain hydrophilic part and a bulky hydrophobic part. Addition of the diblock-copolymer leads to an enhancement of the swelling of the middle phase by uptake of water and oil; a maximum boosting factor of 6 was obtained for PEO111PEDODO25. Nuclear magnetic resonance diffusometry yields the self-diffusion coefficients of all the components in the system. The diffusion experiments provide information on how the microstructure of the bicontinuous microemulsion changes upon addition of the polymers. The reduced self-diffusion coefficients of water and oil are sensitive to the type of polymer that is incorporated in the film. For the diblock-copolymers, as mainly used here, the reduced self-diffusion coefficient of oil and water will respond to how the polymer bends the film. When the film bends away from water, the reduced self-diffusion of the water will increase, whereas the oil diffusion will decrease due to the film acting as a barrier, hindering free diffusion. The self-diffusion coefficient of the polymer and surfactant are similar in magnitude and both decrease slightly with increasing polymer concentration.

The insula is anatomically situated to be critically involved in many bio-behavioral functions impaired in schizophrenia. Furthermore, its total volume has been shown to be reduced in schizophrenia. In the present study, we tested the hypothesis that in schizophrenia it is the anterior insular lobule (aINS(lbl)) rather than the posterior insular lobule (pINS(lbl)) that is smaller, given that limbic system abnormalities are central in schizophrenia and that the affiliations of the limbic system are principally with the anterior insular lobule. We used T1-weighted high resolution magnetic resonance imaging (MRI) to measure the cortical volume of the left and right anterior and posterior insular subdivisions. The subjects included a sample of healthy community controls (N=40) and chronic patients with DSM-III-R schizophrenia (N=41). We correlated insula volumes with positive and negative symptoms. We found that the total aINS(lbl), and the left aINS(lbl) in particular, were significantly volumetrically smaller in schizophrenia compared to controls, and significantly correlated with bizarre behavior. Given that the anterior insular lobule offers anatomic features that allow for MRI-based morphometric analysis, namely its central and circular sulci, this brain structure provides a useful model to test hypotheses regarding genotype-phenotype relationships in schizophrenia using the anterior insular lobule as a candidate endophenotype.

There is a lack of studies mapping electrophysiological event-related potentials (ERPs) to structural neuroanatomical characteristics. The aim of the present study was to integrate electrophysiological memory-related activity with cortical and hippocampal volume, as well as psychometric memory performance, in a life-span sample. More specifically, we wanted to investigate the functional significance of the often-observed frontal shift of ERP amplitude with increasing age and whether neuroanatomical characteristics can explain this shift. Sixty six healthy participants (20-78 years) went through a neuropsychological examination, MRI scans, and a visual recognition ERP task with verbal stimuli. The results showed that ERPs elicited in the recognition memory task (the old/new effect) correlated significantly with cortical volume, but not with hippocampal volume. Large cortex predicted more differentiated ERP activity and not just larger amplitude in general, implying more distinct and efficient retrieval. Furthermore, ERP amplitude, cortical volume, and hippocampal volume all predicted scores on a composite memory scale. All these relationship were dependent upon the common influence of age. Finally, the participants with the most anterior distribution of activity showed the poorest recognition memory performance. Neither cortical nor hippocampal volume were related to this frontal shift. It is concluded that the distribution of activity along the anterior-posterior axis in a memory paradigm may have functional but not neuroanatomical volumetric correlates. The functional correlates need not be restricted to the older age groups.