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Biomedical subjects

A Bartolo

Publications and source records attributed to A Bartolo.

7 recordsLinked to original sources

Pantomimes are special gestures which rely on working memory.

The case of a patient is reported who presented consistently with overt deficits in producing pantomimes in the absence of any other deficits in producing meaningful gestures. This pattern of spared and impaired abilities is difficult to reconcile with the current layout of cognitive models for praxis. This patient also showed clear impairment in a dual-task paradigm, a test taxing the co-ordination aspect of working memory, though performed normally in a series of other neuropsychological measures assessing language, visuo-spatial functions, reasoning function, and executive function. A specific working memory impairment associated with a deficit of pantomiming in the absence of any other disorders in the production of meaningful gestures suggested a way to modify the model to account for the data. Pantomimes are a particular category of gestures, meaningful, yet novel. We posit that by their very nature they call for the intervention of a mechanism to integrate and synthesise perceptual inputs together with information made available from the action semantics (knowledge about objects and functions) and the output lexicon (stored procedural programmes). This processing stage conceived as a temporary workspace where gesture information is actively manipulated, would generate new motor programmes to carry out pantomimes. The model of gesture production is refined to include this workspace.

Aged↗

An arrhythmia detector and heart rate estimator for overnight polysomnography studies.

We present an algorithm for automatic on-line analysis of the electrocardiography (ECG) channel acquired during overnight polysomnography (PSG) studies. The system is independent of ECG morphology, requires no manual initialization, and operates automatically throughout the night. It highlights likely occurrences of arrhythmias and intervals of bad signal quality while outputting a continual estimate of heart rate. Algorithm performance is validated against standard ECG databases and PSG data. Results demonstrate a minimal false negative rate and a low false positive rate for arrhythmia detection, and robustness over a wide range of noise contamination.

Algorithms↗

The polysomnogram assay: a method to represent the overnight polysomnogram in a condensed format.

We present the polysomnogram assay (PSGA), a new representation format for the polysomnogram (PSG), designed to assist in the interpretation of overnight PSG studies. The technique condenses the PSG record by a factor of 30 while preserving the ability to portray PSG features of diagnostic relevance, including sleep architecture, arousals, movement, leg jerks, cyclic alternating pattern, and increased breathing effort. The PSGA patterns associated with these events are described and illustrated by examples. The new format considerably reduces the effort required to evaluate sleep quality and continuity, making it more practicable for the polysomnographer to interpret the entire overnight PSG study. The compressed time scale also facilitates analysis of relatively long PSG episodes and allows assessment of signal activity surrounding critical PSG events. The PSGA appears capable of improving identification of arousals, leg jerks, and upper airway resistance, and may be especially amenable for automatic analysis of PSG data.

Airway Resistance↗

Analysis of diaphragm EMG signals: comparison of gating vs. subtraction for removal of ECG contamination.

The diaphragm electromyogram (EMGdi) conveys information relating to the mechanisms of respiration; however, electrocardiogram (ECG) contamination can compromise the accuracy of data derived from this signal. We examine the EMGdi recorded from anesthetized spontaneously breathing dogs via implanted electrodes to assess the extent of the error introduced by the ECG contamination and the effectiveness of ECG gating in reducing this error. Because ECG subtraction has been shown to generate accurate results for such applications, it is used as the gold standard. Analysis of variance methods are employed to compare results derived from the EMGdi data after ECG subtraction with corresponding results derived from the original data and from the data after ECG gating. Estimates of EMGdi variables obtained by using subtraction and gating techniques were not significantly different, indicating that gating can be employed on these signals to reduce ECG contamination without affecting the accuracy of the derived data. Results also show that at EMG-to-ECG power ratios > 13.3 dB, ECG contamination does not significantly affect estimates of the EMGdi variables.

Animals↗

[Acute pericarditis in childhood. The 9-year experience of a tertiary referral center].

Sixteen children, aged 7 months to 12 years, with acute pericarditis, admitted between 1985 and 1993 to a tertiary referral centre were analyzed retrospectively for their presentation, etiology, work-up, management and prognosis. It was found that most of the presenting signs were not specific and were often related to associated diseases such as respiratory tract infections. In 50% of the cases a cause was not found, the others had viral infections (12.5%), tuberculosis (12.5%), Haemophilus influenzae infection (6.25%), Toxocara canis infection (6.25%) and collagen diseases (12.5%). In eight cases non-steroidal anti-inflammatory drugs associated with steroids were given, 7 patients received non-steroidal anti-inflammatory drugs and 1 steroids. The mean follow-up time was 3 years (1 to 5). Six patients had one or more relapses. Five of the 6 patients with relapses were in the group which received steroids. The two patients with tuberculosis underwent pericardiectomy. One child died due to complex heart disease and the remaining 15 were cured. It was concluded that in pericarditis an extensive work-up may not reveal the major etiologies and that long term prognosis is good.

Acute Disease↗