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Biomedical subjects

P W Jamieson

Publications and source records attributed to P W Jamieson.

9 recordsLinked to original sources
PubMed1994

Idiopathic generalized myokymia.

Idiopathic generalized myokymia (IGM) is a rare, heterogeneous, and poorly understood syndrome. We present analysis of 75 reported cases in the world literature. IGM affects men and women equally, with a mean age of onset 29 +/- 19 years. Patients' common presenting complaints are stiffness (60%), cramps (12%), weakness (12%), and muscle twitching (4%). Family history is positive in 30%. In addition to generalized clinical myokymia (92%), abnormal neurologic findings include: hyporeflexia (70%), weakness (45%), grip myotonia (39%), and calf hypertrophy (16%). Electrical activity consisting of spontaneous continuous motor unit activity and/or electrical myokymia was documented in all patients. When electrical myokymia was observed (66%), the grouped discharges where irregular and had an interburst frequency of 2-300 Hz. Both phenytoin and carbamazepine are effective treatments. We conclude that IGM has a wide spectrum of symptoms and severity and should be considered in all patients that present with stiffness, cramps, or muscle twitching. EMG greatly aids in diagnosis.

Adult↗
PubMed1992

Neurology research: a journal survey, 1980-1990.

There have been major changes in neurology research during the past decade, but no systematic examination of the content, methods, funding, and research personnel. All scientific articles in the journals Annals of Neurology, Archives of Neurology, and Neurology were categorized by article type, number of authors, highest degree of first author, institution, disease area, research field, and source of support for the years 1980 and 1990. Original articles grew by 54% over the decade. The average number of authors increased by 1.3 to 5 (p greater than 0.0001). Groups of MDs and PhDs wrote 39% of articles in 1990 (24% in 1980). Contributions with a diagnostic or therapeutic focus rose from 7 to 14%, whereas there was a pronounced drop in case reports from nearly 40% to just under 20%. Articles on movement disorders and neurodegenerative diseases increased more than 100% and now together comprise more than 25% of original articles. Molecular biology increased by 1,600%, and there was significant growth in epidemiology, neuro-imaging, neurochemistry, and neuropsychology. The top 20 publishing institutions accounted for 40% of all original articles and 60% of US original articles. Foreign contributions doubled over the decade. The National Institutes of Health funded 46% of US articles in 1990 (35.5% in 1980). More than 80% of articles in 1990 on neurodegenerative disease were supported by the National Institutes of Health. The complexity of neurological research has driven greater collaboration between basic and clinical scientists. New areas of clinical and basic knowledge are rapidly emerging in neurology.

Animals↗
PubMed1991

A model for diagnosing and explaining multiple disorders.

The ability to diagnose multiple interacting disorders and explain them in a coherent causal framework has only partially been achieved in medical expert systems. This paper proposes a causal model for diagnosing and explaining multiple disorders whose key elements are: physician-directed hypotheses generation, object-oriented knowledge representation, and novel explanation heuristics. The heuristics modify and link the explanations to make the physician aware of diagnostic complexities. A computer program incorporating the model currently is in use for diagnosing peripheral nerve and muscle disorders. The program successfully diagnoses and explains interactions between diseases in terms of underlying pathophysiologic concepts. The model offers a new architecture for medical domains where reasoning from first principles is difficult but explanation of disease interactions is crucial for the system's operation.

Acid-Base Imbalance↗
PubMed1991

A computational model of levodopa pharmacodynamics in Parkinson's disease.

A series of computational models were developed to better understand basal ganglia functions and the effects of levodopa pharmacodynamics in Parkinson's disease. The models employed a relatively new computational approach known as a neural network, which is a small number of simple processing units interconnected with designated constraints. A key difference from traditional computational modeling is that the networks are "trained" rather than programmed with experimental input and output data. After training, only a limited number of these models, could explain the pharmacodynamic data observed by Mouradian et al. in different groups of Parkinsonian patients. These successful models strongly argue for at least two pharmacologic mechanisms to explain the antiparkinsonian effect and dyskinesia tendency for the different classes of Parkinson's patients: never-treated, stable, wearing-off, and on-off. They suggest different roles for the striatal units by examining predictions of motor and dyskinesia tendency through theoretical blockade of each kind of unit. The models show that the antiparkinsonian effect in Parkinson's disease cannot be explained by the action of dopaminergic neurons on striatal neurons alone. Although the models necessarily oversimplify basal ganglia function, they provide a useful quantitative insight into how motor and dyskinesia behaviors may develop in different Parkinsonian subgroups.

Basal Ganglia↗
PubMed1991

Necrotizing angiopathy presenting with multifocal conduction blocks.

We describe conduction block as an unusual electrophysiologic manifestation in a patient with necrotizing angiopathy. The patient developed subacute symptoms over a 1-month period consisting of progressive pain, tingling, and weakness of the lower extremities. Physical examination revealed a pattern consistent with a polyneuropathy. Electrodiagnostic studies provided evidence of a conduction block in the left ulnar nerve. Pathologic studies confirmed the process to be a necrotizing angiopathy. This report establishes the role of conduction block in human nerve ischemia.

Electrodiagnosis↗
PubMed1990

Computerized interpretation of electromyographic data.

A computer program was developed to plan, interpret and report the analysis of electromyographic data. The computer model formalized electrodiagnostic decisions through the use of a computational method known as augmented transition networks (ATN). The diagnoses of entrapment neuropathies, plexopathies, and radiculopathies were incorporated into the computer model. The system analyzed a difficult set of electromyographic (EMG) cases and the computer and physician reached the same conclusion 78% of the time. The system could explain the reason it reached its diagnostic conclusions and report to the physician all the relevant pathophysiologic derangements. The system could also offer advice on how one could strengthen a tentative diagnostic conclusion. While this system is limited in its diagnostic coverage of EMG problems, it may be a useful assistant to the electromyographer by focusing attention on significant pathophysiologic derangements detected on EMG examination.

Diagnosis, Computer-Assisted↗
PubMedDate not supplied

A new paradigm for explaining and linking knowledge in diagnostic problem solving.

Medical expert systems frequently use causal models to capture knowledge and diagnostic-problem-solving expertise. A significant obstacle confronting these systems is providing informative explanations without prohibitive computational expense. The explanations should allow the user to understand the decisions of the expert system and obtain additional details when needed. A new method, called HyperExplain, has been devised to flexibly link explanations with conclusions generated by a causal reasoning system. This approach creates a patient specific explanatory (PSE) model for the medical expert system that provides decision support from a variety of perspectives. A key feature of this method is the ability to alter the focus of explanations depending upon the problem-solving context and patient manifestations. The method has been implemented in a program that provides diagnostic assistance to physicians in the domain of neurophysiology.

Artificial Intelligence↗
PubMedDate not supplied

Automating clinical practice guidelines: a corporate-academic partnership.

Implementation of guidelines offers one of the largest opportunities for quality improvement, utilization review, and cost control for the health-care enterprise. If guidelines could be implemented on a large scale, their adoption could result in $100 billion in annual savings as well as improve the quality of patient care. However, infrastructural barriers impede progress. Collaboration between the Laboratory Medicine Health Services Program at the University of Alabama at Birmingham, Columbia-Presbyterian Medical Center, and the Cerner Corporation, funded by the National Institute of Standards and Technology as part of the Advanced Technology Program involving ¿Information Infrastructure for Healthcare,¿ is focused on developing and delivering: 1) methods for creating operational forms of guidelines; 2) an effective computer-based architecture for implementing guidelines in clinical practice; 3) methods for packaging guidelines for wide distribution; 4) methods for testing the efficacy, safety, and acceptability of guidelines; and 5) a model for collecting, aggregating, and normalizing data from disparate systems. This hypothesis-driven research program is focused on laboratory medicine-based guidelines as a tool for developing, testing, and evaluating methods that can be implemented widely.

Academic Medical Centers↗