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Biomedical subjects

M M Cohen

Publications and source records attributed to M M Cohen.

At least 127 records · Page 7Linked to original sources
PubMed1996

Reduction of the elevator illusion from continued hypergravity exposure and visual error-corrective feedback.

Ten subjects served as their own controls in two conditions of continuous, centrifugally produced hypergravity (+2 Gz) and a 1-G control condition. Before and after exposure, open-loop measures were obtained of (1) motor control, (2) visual localization, and (3) hand-eye coordination. During exposure in the visual feedback/hypergravity condition, subjects received terminal visual error-corrective feedback from their target pointing, and in the no-visual feedback/hypergravity condition they pointed open loop. As expected, the motor control measures for both experimental conditions revealed very short lived underreaching (the muscle-loading effect) at the outset of hypergravity and an equally transient negative aftereffect on returning to 1 G. The substantial (approximately 17 degrees) initial elevator illusion experienced in both hypergravity conditions declined over the course of the exposure period, whether or not visual feedback was provided. This effect was tentatively attributed to habituation of the otoliths. Visual feedback produced a smaller additional decrement and a postexposure negative after-effect, possible evidence for visual recalibration. Surprisingly, the target-pointing error made during hypergravity in the no-visual-feedback condition was substantially less than that predicted by subjects' elevator illusion. This finding calls into question the neural outflow model as a complete explanation of this illusion.

Adult↗
PubMed1996

Perceiving speech from inverted faces.

We examined whether the orientation of the face influences speech perception in face-to-face communication. Participants identified auditory syllables, visible syllables, and bimodal syllables presented in an expanded factorial design. The syllables were /ba/, /va/, /oa/, or /da/. The auditory syllables were taken from natural speech whereas the visible syllables were produced by computer animation of a realistic talking face. The animated face was presented either as viewed in normal upright orientation or inverted orientation (180 degrees frontal rotation). The central intent of the study was to determine if an inverted view of the face would change the nature of processing bimodal speech or simply influence the information available in visible speech. The results with both the upright and inverted face views were adequately described by the fuzzy logical model of perception (FLMP). The observed differences in the FLMP's parameter values corresponding to the visual information indicate that inverting the view of the face influences the amount of visible information but does not change the nature of the information processing in bimodal speech perception.

Adult↗
PubMed1995

Neoplasms in Proteus syndrome.

We report on 2 children with Proteus syndrome who developed neoplasms. Patient 1 had a probable mesothelioma, although papillary carcinoma of the thyroid could not be completely ruled out. Patient 2 had bilateral ovarian serous cystadenomas with nuclear atypia. Other unusual neoplasms in Proteus syndrome are discussed, together with their etiologic and pathogenetic possibilities.

Adult↗
PubMed1995

Hands and feet in the Apert syndrome.

We studied 44 pairs of hands and 37 pairs of feet in Apert syndrome, utilizing clinical, dermatoglyphic, and radiographic methods. We also studied histologic sections of the hand from a 31-week stillborn fetus. Topic headings discussed include: clinical classification of syndactyly; correlations between types of hands and feet in the same patient; dermatoglyphics; anatomy of the hand; radiologic assessment; comparison with other studies; histologic assessment of the hand; acrocephalosyndactyly vs. acrocephalopolysyndactyly: a pseudodistinction; and some generalizations.

Acrocephalosyndactylia↗
PubMed1995

Trisomy 7p resulting from isochromosome formation and whole-arm translocation.

A newborn boy with a large anterior fontanel, minor facial anomalies, postaxial polydactyly, patent ductus arteriosus, and developmental delay had trisomy of 7p due to an i(7p) and a concomitant t(2;7) (q37.3;q11.1). Significant enlargement of the fontanel is the most characteristic finding in most patients with duplications involving 7p15-pter. Asynchrony in fore- and hindbrain and hemisphere formation leading to brain asymmetry and various defects in the posterior fossa are typical of infants with duplications of 7p11-p12. A variety of heart defects has also been found in more than 50% of patients with duplication of 7p segments. Isochromosome formation accompanied by whole-arm translocation, resulting in uniparental isodisomy for the involved segment, is an extremely rare cause leading to partial trisomies. Although it is not clear whether isochromosome formation precedes the whole-arm translocation or follows it, the secondary rearrangement may have adaptive significance.

Abnormalities, Multiple↗
PubMed1995

Technology assessment of anaesthesia monitors: problems and future directions.

Specific factors have limited the interpretation of studies regarding the efficacy, effectiveness and efficiency of technology in anaesthesia. Some of these problems are reviewed, including the lack of specific outcomes necessitating the use of intermediate measures (e.g., hypoxaemia, myocardial ischaemia), which are not necessarily related to ultimate patient outcomes. This emphasizes the need for anaesthesia investigators to define fundamental issues specifically and design studies accordingly. With respect to anaesthesia monitors, the "lead time" or early warning provided by a monitor relative to that required to alter therapy effectively needs to be defined better and compared with the "lead time" without the monitor. After defining the benefit of a monitor, investigators should analyze the cost relative to alternatives (cost-benefit and cost-effectiveness). A hierarchical model to guide technology assessment is presented that addresses in order, the scientific basis of the technology, and the influence on the patient followed by societal issues. Anaesthetists have relied on traditional methods of technology assessment adopted from other disciplines. These methodologies do not address specific issues related to anaesthesia practice (such as "lead time"). In defining problems specific to the specialty of anaesthesia, new outcome measures that focus on the human factors related to decision-making in the operating room need to be developed. Future evaluations of anaesthesia technology require innovative approaches that address specific anaesthesia-related problems. One such approach is the use of simulation-based studies of response patterns to critical incidents.

Anesthesiology↗
PubMed1995

Continuous versus discrete information processing in pattern recognition.

A discrete feature model (DFM) and the fuzzy logical model (FLMP) were formulated to predict the distribution of rating judgments in a pattern recognition task. The distinction was between the spoken vowels /i/ and /I/, as in beet and bit. Subjects were instructed to rate the vowel on a nine-point scale from /i/ to /I/. Two features, the first formant frequency (F1) and the vowel duration, were orthogonally varied: The vowel /i/ has a lower (F1) and a longer duration compared to a somewhat higher (F1) and shorter duration for /I/. The DFM predicts that the separate features are recognized discretely, whereas the FLMP assumes that continuous information is available about each feature. Tests of these models on the observed data indicated that the continuous information assumption of the FLMP gave a significantly better description of the distribution of rating judgments.

Adult↗
PubMed1995

Manitoba's population-based databases and long-term planning: beyond the hospital databases.

The Manitoba Centre for Health Policy and Evaluation (MCHPE) conducts health services research focusing on Manitoba's administrative databases. Administrative databases contain information which is routinely and systematically collected for administrative purposes such as hospital and physician claims and funding requirements. This article describes the MCHPE's five major databases, their strengths and limitations, and the development of the Population Health Information System (PHIS). Four modules from PHIS illustrate how the data are used to provide useful information for health care planners, administrators and policy analysts. Finally, future projects and directions for using administrative databases are explored.

Data Collection↗
PubMed1995

Hypertelorism: interorbital growth, measurements, and pathogenetic considerations.

Normal pre- and post-natal changes in the interorbital distance are described. Causes of illusory hypertelorism include flat nasal bridge, epicanthic folds, exotropia, widely-spaced eyebrows, narrow palpebral fissures, and dystopia canthorum. Measurements of hypertelorism may involve soft tissues or bone, and a number of indices have also been proposed. Various types of measurements are evaluated and recommendations suggested. Possible pathogenetic mechanisms for hypertelorism include: early ossification of the lesser wings of the sphenoid; failure in nasal capsule development allowing the primitive brain vesicle to protrude into the space normally occupied by the capsule resulting in morphokinetic arrest in the position of the eyes; and disturbances of the cranial base in Apert syndrome. Associations with increased interorbital distance are also discussed: orofacial clefting, nonprotruding lipomas of the corpus callosum, calcification of the falx cerebri, duplication of the crista galli, wrinkling of the nose, and tissue tags of the nose. Finally, experimental models of hypertelorism in animals are discussed.

Abnormalities, Multiple↗
PubMed1995

Perspectives on craniofacial asymmetry. I. The biology of asymmetry.

Part I introduces the survey and presents a topic outline of the six parts that make up this series of articles on craniofacial asymmetry. The discussion in Part I considers normal variation, normal and abnormal laterality, types of anomalies that may be asymmetric, and finally, some well-known causes of craniofacial asymmetry.

Facial Asymmetry↗
PubMed1995

Perspectives on craniofacial asymmetry. III. Common and/or well-known causes of asymmetry.

Mandibular asymmetry may be caused by infection or trauma. Unilateral facial paralysis has many causes and Bell's palsy, which is idiopathic, is the most common type. Asymmetric muscle involvement is discussed, including the masseter, temporalis, depressor anguli oris, extraocular, and sternocleidomastoid muscles. Tumors that present asymmetrically are also considered, including the juvenile hemangioma, lymphangioma, osteoma, embryonal rhabdomyosarcoma, and Burkitt's lymphoma. Finally, some miscellaneous conditions are discussed, including fibrous dysplasia, mucus retention phenomenon, electrical burns of the mouth, and cancrum oris.

Burns, Electric↗
PubMed1995

Perspectives on craniofacial asymmetry. IV. Hemi-asymmetries.

Hemi-asymmetries discussed here include: 1) hemihyperplasia which may affect either one tissue such as bone with secondary regional consequences or multiple tissues on a primary basis such as "hemihypertrophy"; 2) hemihypoplasia which may also affect one tissue such as bone with secondary regional consequences or multiple tissues on a primary basis such as in hemifacial microsomia; 3) hemiatrophy, the quintessential craniofacial disorder being Romberg syndrome; and 4) miscellaneous conditions such as Bencze syndrome and hemimaxillofacial dysplasia.

Abnormalities, Multiple↗
PubMed1995

Perspectives on craniofacial asymmetry. V. The craniosynostoses.

The craniosynostoses are both etiologically and pathogenetically heterogeneous and many syndromes have been delineated. The present paper highlights well-known craniosynostoses that can present asymmetrically. These include plagiocephaly resulting from premature unilateral synostosis of the coronal or lambdoid sutures. Apert syndrome, and Saethre-Chotzen syndrome.

Acrocephalosyndactylia↗
PubMed1995

Perspectives on craniofacial asymmetry. VI. The hamartoses.

The hamartoses are a large group of disorders with autosomal dominant inheritance or sporadic occurrence. The genes responsible for some have been localized to specific chromosomes and in several instances, genetic heterogeneity has been established. Thus neurofibromatosis and tuberous sclerosis are no longer single entities. For example, the gene for Type I neurofibromatosis is on chromosome 17 and the gene for Type II is on chromosome 22. In this paper, genetic aspects of the hamartoses are updated and asymmetry is discussed in Sturge-Weber angiomatosis, epidermal nevus syndrome, Gardner syndrome, neurofibromatosis, and Proteus syndrome.

Chromosomes, Human, Pair 17↗