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M Spitzer

Publications and source records attributed to M Spitzer.

At least 73 records · Page 4Linked to original sources
PubMed1996

Functional MR imaging of semantic information processing and learning-related effects using psychometrically controlled stimulation paradigms.

Functional magnetic resonance imaging (fMRI), in conjunction with carefully designed, psychometrically optimized stimulation procedures, was used to investigate the relation between brain activation and the processing of word associations. A semantic discrimination task of word-pair similarity was performed by normal subjects (n = 17) within a clinical 1.5-Tesla whole-body MRI system. A color similarity task of psychometrically equivalent difficulty, as indicated by behavioral data acquired online during fMRI, served as active control condition. Comparisons between tasks dramatically improved results compared to comparisons between task and resting condition. The language paradigm selectively activated left frontal and left fronto-temporal areas. Cortical activation during the semantic task decreased significantly over three runs of the same word list and was paralleled by decreased reaction times. No such changes were observed in the active control condition indicating selective learning of the language task only. When combined with psychological activation schemes and the acquisition of behavioral data, fMRI represents a powerful tool for the study of brain-behavior interaction.

Adult↗
PubMed1996

Repair of laparoscopic injury to abdominal wall arteries complicated by cutaneous necrosis.

Operative laparoscopic techniques requiring placement of large-bore cannulas through the abdominal wall lateral to the midline result in increased numbers of injuries to abdominal wall vessels. Five cases of inferior epigastric artery hemorrhage were controlled by percutaneous transabdominal placement of polypropylene sutures, allowing the procedure to be completed with the cannula in place. In two patients the sutures were left in place for 72 to 96 hours, and cutaneous necrosis occurred requiring debridement and delayed primary closure. In the other three women, removal of the sutures less than 24 hours postoperatively resulted in satisfactory hemostasis and primary healing of the abdominal wound. Percutaneous placement of polypropylene sutures may provide effective hemostasis after inferior epigastric artery hemorrhage due to cannula injury. Early suture removal may avoid potential cutaneous necrosis.

Abdominal Muscles↗
PubMed1996

[Functional magnetic resonance tomography during the activation of working memory].

AIMS: Functional magnetic resonance imaging was used in conjunction with a letter detection task for the study of working memory in 16 normal subjects. Because of movement artifacts, data from only 9 subjects were analysed. METHODS: In the activation task, subjects responded by pressing a button whenever any presented letter was the same as the second last in the sequence. In the control condition, the subjects had to respond to a fixed letter. Hence, the activation condition and the control condition differed only subjectively, i.e., regarding the task demand, whereas the stimuli and the type and frequency of response were identical. RESULTS: The activation condition produced significant activation in the dorsolateral prefrontal cortex (Brodmann's areas 10, 46, and 9). CONCLUSIONS: In contrast to experimental tasks previously used rather extensively to study the prefrontal cortex, the present paradigm is characterized by its simplicity, interpretability, and its ties to known neurophysiology of the frontal cortex.

Adult↗
PubMed1996

[Triggered transcranial magnetic stimulation in high cognitive functions].

Transcranial magnetic stimulation (TMS) can be triggered and thereby allows the reversible manipulation of cortical information processing. A magnetic field is induced by a coil which produces a current which has an excitatory or inhibitory effect on the underlying cortex. Triggered TMS has been used to assess the visual system and lately the method was also applied to higher cognitive functions. The method has good spatial and temporal resolution and it can be combined with other neuroscience and experimental psychological methods. We provide an overview on TMS research and present the results of a study. Possible applications and limitations of the method are discussed with respect to basic research as well as diagnostic and therapeutic implications.

Adult↗
PubMed1996

[Hallucinogen induced psychic disorders. Subjective experiences, psychopathology and differential diagnosis].

The concepts of intoxication, intoxication psychosis, and drug-induced psychosis are frequently used to refer to psychopathological states caused by the intake of hallucinogenic substances. The considerable increase of intoxications with substances of the chemical class of amphetamines (in particular, "Ecstasy") in western countries should cause major concern. Moreover, the number of schizophrenic patients who also use hallucinogenic drugs is increasing. High incidence and comorbidity cause clinical problems and call for detailed knowledge of the drug related acute and chronic effects of the various agents currently in use. Clinical findings and subjective reports from research in experimental psychoses are used to discuss differential diagnosis and types of drug-induced mental disorders within the framework of present day classificatory systems, such as DSM-IV and ICD-10.

Adolescent↗
PubMed1996

Noise in models of neurological and psychiatric disorders.

The concept of noise has only recently been applied to modelling neuropsychiatric disorders. Two examples of such models are presented. 1. A phantom limb is a neurological condition after the amputation of an extremity. It consists of sensations of the presence of the lost limb and has been attributed to cortical as well as non-cortical mechanisms. A neural network model of phantom limbs is proposed which can parsimoniously account for a large number of clinical features and recent findings of cortical map plasticity after deafferentation. In trained self-organizing feature maps, deafferentation was simulated. Reorganization is shown to be driven by input noise. According to the model, the production of input noise by the deafferented primary sensory neuron drives cortical reorganization in amputees. No such noise is generated and/or conducted to the cortex in paraplegics. 2. Several clinical features of schizophrenia have been related to the ratio of signal to noise in neuronal information processing. In particular, dopamine--which has been implicated in the causation of schizophrenia for decades--has been proposed to modulate signal-to-noise ratio. Data are presented which suggest that schizophrenic thought disorder is the result of a hypodopaminergic state and concomitant increased effects of noise in semantic information processing. Possible functions of noise in the nervous systems are discussed.

Computer Simulation↗
PubMed1995

Category-specific brain activation in fMRI during picture naming.

Neuropsychological, computational, and psycholinguistic data suggest the existence of semantic maps, i.e. localized representations of semantic information in the brain. Using functional magnetic resonance imaging, this hypothesis was directly tested with a picture naming task involving items from four different semantic categories. Small left lateralized fronto-temporal cortical sites of category-specific activation were found when brain activation signals were averaged. Data suggest the existence of multiple maps coding high-level representations of objects, such that meaningful distinctions, at least in part, govern the physical distribution of cortical semantic storage.

Brain Mapping↗
PubMed1995

A neural network model of phantom limbs.

This paper presents a detailed clinical description of phantom limbs and a neuronal network model that provides a comprehensive and parsimonious explanation of otherwise inexplicable or at least unrelated phenomena. Simulations of self-organizing feature maps (Kohonen networks) that had been trained to recognize input patterns were deprived of parts of their input in order to simulate partial deafferentation. This leads to reorganization processes that are shown to be driven by input noise. In patients with an amputated limb, this noise is generated by dorsal root ganglion sensory neurons which are known to fire irregularly upon laceration. According to this model, the long-standing debate concerning non-cortical vs. cortical contributions to the generation of the phenomenon of phantom limbs can be resolved in that it is the peripherally generated noise that causes cortical reorganization. The model can be tested and may have therapeutic implications.

Cerebral Cortex↗
PubMed1995

The fertility of women after cervical laser surgery.

OBJECTIVE: To retrospectively survey our population of women who had undergone cervical laser surgery to determine if it adversely affected their ability to conceive or to carry a pregnancy to term. METHODS: Women who had undergone laser surgery during the period 1979-1989 were contacted and surveyed regarding each of their pregnancies. Information obtained included their age at the time of each pregnancy, pregnancy outcome, how long they were trying to conceive, and their use of contraception. The post-laser experience of the study group was matched individually for age and parity with a control population taken from the pre-laser interval of the same patients. RESULTS: We contacted 1069 women; 512 responded to the survey and 433 were matched with controls. The mean study interval was 3.8 years. The study group had significantly more total pregnancies (277 versus 177 for controls, P < .001), total births (163 versus 112 for controls, P < .002), full-term pregnancies (145 versus 100 for controls, P < .005), and terminations of pregnancy (75 versus 28 for controls, P < .001). There was no significant difference in the number of spontaneous abortions (31 for the study group and 33 for controls), premature deliveries (18 for the study group and 12 for controls) or ectopic pregnancies (eight for the study group and four for controls). There was no difference in the pregnancy rate (compared with controls) between laser vaporizations and excisions. CONCLUSION: Cervical laser surgery does not appear to impair a woman's ability to conceive or carry a pregnancy to term. There is no difference in the effect on fertility between laser vaporization and laser excisional cone biopsies.

Adult↗
PubMed1995

Luteal phase defects and ectopic pregnancy.

OBJECTIVE: To determine whether luteal phase defect (LPD) may be an etiologic factor in ectopic pregnancy (EP). DESIGN: All patients who were seen over a 6-year period with the chief complaint of infertility underwent an extensive infertility workup and were followed prospectively. The diagnoses of the causes of infertility were assigned retrospectively. SETTING: Two hospital-based tertiary care reproductive endocrine-infertility units. PATIENTS: A total of 1,077 infertility patients were evaluated. Of the 633 who became pregnant, the infertility had been due to LPD in 51 and to anovulation in 210. MAIN OUTCOME MEASURES: All the infertility patients who became pregnant were followed to determine whether they miscarried, developed an EP, or had a viable birth. The incidence of EP and miscarriage in the patients whose infertility was found to be due to LPD were compared with a control group in whom the infertility was due to anovulation. RESULTS: The EP rate in the patients with LPD was significantly higher than in a control group whose infertility was due to anovulation (6 of 51 pregnancies versus 6 of 210 pregnancies, respectively). The spontaneous abortion rate in LPD cases also was highly significantly greater than in the control group (19 of 51 pregnancies versus 12 of 210 pregnancies, respectively). The EP and spontaneous abortion rates also were higher in patients with LPD who were untreated than in those who were treated. CONCLUSIONS: This study suggests that there is a significantly increased incidence of tubal EP in patients with LPD and that when patients with LPD become pregnant early ultrasound should be performed to rule out EP. The study also indicated that spontaneous abortion occurs in a significantly high percentage of LPD cases.

Female↗
PubMed1995

[Ovarian stimulation with gonadotropins in undetected tubal pregnancy within the scope of in vitro fertilization].

The authors report on a patient who was pretreated with a depot GnRH-analog previous to exogenous gonadotropin stimulation before in-vitro fertilisation (IVF). The patient had an undiagnosed ectopic pregnancy. Folliculogenesis and the hormone profile were normal. In patients with patent tubes, contraception (non-hormonal) in the cycle previous to IVF should be performed.

Adult↗
PubMed1995

Ascites due to endometriosis.

Ascites is a rare but important complication of endometriosis because it mimics ovarian cancer. Most cases occur in nulliparous young black women and present with massive ascites. Treatment is effected by ablation of ovarian function by surgery, radiotherapy, or suppression of endometriosis by endocrine therapy. The pathogenesis is unknown. In this paper, we present a case report and review of the other 19 cases in the literature. Because of the age of most of these women, endocrine therapy is preferred rather than castration. The majority of symptoms and signs of endometriosis are well known, including pelvic pain, dysmenorrhea, dyspareunia, infertility, and pelvic tenderness with or without masses. However, it is seldom appreciated that the disease can be a cause of, and can present with ascites, often massive and recurrent. It is important for gynecologists and oncologists to be aware of this entity because the presence of ascites with abdominal and/or pelvic masses and weight loss immediately suggests the diagnosis of malignancy, and the possibility of endometriosis is rarely considered. We are reporting a case of endometriosis causing massive and recurrent ascites, along with a review of the literature and a discussion of the epidemiology, pathogenesis, and management of this disorder.

Adult↗
PubMed1995

[Neurofunctional MRI imaging of higher cognitive performance of the human brain].

Functional magnetic resonance imaging (fMRI) offers a powerful experimental tool for mapping activated cortical regions in man. Thereby, the paramagnetic deoxyhemoglobin in the red blood cells acts as an endogenous susceptibility contrast agent, which allows the noninvasive detection of stimulus-induced transient changes in regional cerebral blood flow and volume. Fifteen normal subjects were examined on a conventional 1.5-T MR system to visualize cortical activation during the performance of high-level cognitive tasks. A computer-controlled videoprojector was employed to present psychometrically optimized activation paradigms. Reaction times and error rates of the volunteers were acquired online during stimulus presentation. The time course of cortical activation was measured in a series of strongly T2*-weighted gradient-echo images from three or four adjacent slices. For anatomical correlation, picture elements showing a stimulus-related significant signal increase were color-coded and superimposed on T1-weighted spin-echo images. Analysis of the fMRI data revealed a subtle (range 2-5%), but statistically significant (P < 0.05) increase in signal intensity during the periods of induced cortical activation. Judgment of semantic relatedness of word pairs, for example, activated selectively cortical areas in left frontal and left temporal brain regions. The strength of cortex activation in the semantic task decreased significantly in the course of stimulus presentation and was paralleled by a decrease in the corresponding reaction times. With its move into the area of cognitive neuroscience, fMRI calls both for the careful design of activation schemes and for the acquisition of behavioral data. For example, brain regions involved in language processing could only be identified clearly when psychometrically matched activation paradigms were employed. The reaction time data correlated well with selective learning and thus helped to facilitate interpretation of the fMRI data sets.

Arousal↗
PubMed1995

[From degeneration to anticipation. Systematic and historical scientific aspects of the genetics of neuropsychiatric diseases].

Triplet-repeat mutations are a newly discovered class of mutations that have so far been described only in patients with neuropsychiatric disorders. The features of these so-called dynamic mutations are discussed with reference to the known examples (Huntington's chorea, fragile X syndrome, myotonic dystrophy, X-linked spinal and bulbar muscular atrophy, spinocerebellar ataxia type 1, and dentatorubral and pallidoluysian atrophy, DRPLA). These features not only explain a number of clinical-epidemiological facts that cannot be accounted for by Mendelian genetics, but also suggest that schizophrenia and major affective disorder may be the result of a similar mutation mechanism. The most important support for this suggestion can be derived from the observation that dynamic mutations cause anticipation-i.e., an increase in severity and/or an decrease in the age at onset of a disease in subsequent generations-which, in turn, has been discovered in schizophrenia and major affective disorder. From a systematic as well as from a historical perspective, we argue that in light of these findings, degeneration has been rediscovered in the disguise of a new name.

Affective Disorders, Psychotic↗
PubMed1994

Semantic and phonological priming in schizophrenia.

This study of 70 schizophrenic patients used a lexical decision task involving the recognition of words that were preceded (primed) either by meaningfully or phonologically associated or by nonassociated words to study the intrusion of contextually inappropriate associations in thought disorder (TD). The patients were split into subgroups of TD and non-TD patients, and the data from these two groups were compared with data from 44 normal control participants. TD schizophrenic patients exhibited more semantic priming than non-TD patients and controls, and differences in phonological priming dependent on stimulus onset asynchrony (SOA) were obtained. Results support the hypotheses of an increase in activation or a decrease in inhibition in the spreading of semantic and phonological associations in TD schizophrenic patients.

Adult↗
PubMed1994

Pathological fire-setting 1951-1991: a review.

The purpose of this article is to review the whole literature on pathological fire-setting and related fields since 1951 in order to present a state of the art picture of our contemporary knowledge about this phenomenon. Papers were initially selected by using a Medline search. From the articles obtained in this way the references had to be pursued, because many relevant papers and books in this research field of different scientific and practical disciplines are not listed in conventional literature services. Finally, only those contributions were selected which provided new information when published, by original research, theoretical interpretation or practical implications. The last forty years have brought a growing body of data and understanding--especially concerning pathological fire-setting by children--etiology, and therapy, which often proves successful. The situation remains unclear for arson by psychologically disturbed adults and we still have a poor understanding of arson without apparent motive. There is a conflict of opinion as to whether adult fire-setters are suitable for therapy and therapeutic efforts dealing with psychologically disturbed adults are rare. With increasing knowledge about child fire-setting and its successful treatment, etiological and therapeutic models for adult fire-setting behaviour may be developed. Research into the latter area should focus on both biographical and social conditions of development from childhood on as well as biological measures. Both will be reviewed here.

Adolescent↗