Work

Discrimination of cardiac activity

Year: 1987
Type: dissertation
Abstract: This thesis is concerned with techniques for assessing the ability of individuals to detect internal sensations of heartbeats. In order to investigate this issue, a series of experiments was undertaken to examine certain procedural features of conventional heartbeat detection (HBD) tasks. This led to the development of an objective procedure for HBD assessment which was based on individual difference methodology. This procedure was employed to test several hypotheses about individual differences in heartbeat detection ability.The first chapter presents a brief view of the nature and incidence of visceral sensation and introduces some research issues relevant to the study of visceral perception. In light of this, a critical account of the development of procedures employed to assess cardiac perception is presented in Chapter Two. After several unsuccessful attempts to quantify cardiac perceptual ability using paper-and-pencil tests, there was a move towards the development and use of objective techniques for measuring HBD.A variety of new procedures were devised and employed primarily in the investigation of the role of individual differences in the ability to detect heartbeats. The wide variability among the techniques corresponded with an equivalent degree of variability in published results, hence, preventing clear inter-task comparisons. This problem of the lack of standardization of HBD procedures is raised in Chapter Three where it is argued that the role of individual differences in heartbeat detection cannot be addressed until issues concerning the validity and reliability of HBD procedures are properly resolved.The experimental work presented evaluates the essential features of the conventional HBD paradigm, beginning with tests using noncardiac stimuli of whether individuals are capable of making the temporal discriminations required in HBD procedures. The results provided evidence of very accurate temporal discrimination. However, this level of performance was not reflected in performance on a task involving the detection of internal cardiac stimuli. On the basis of the findings it was proposed that poor performance on the HBD tasks could be attributable to the practice in standard HBD procedures of using a single arbitrarily defined criterion for the occurrence of a heartbeat.Hence, a HBD procedure was developed which did not impose a priori judgements of which events the individual will employ in detecting heartbeats. This procedure generated reliable and unambiguous evidence that individuals were detecting as heartbeats, events that occurred 200 to 300 milliseconds after the R-Wave of the cardiac cycle.The procedure was considered a suitable basis for an unbiased test of heartbeat detection and was used to test the individual difference variables mentioned in Chapter Three. The results of those tests led to speculations about the possible sensory pathways mediating the perceptions of heartbeat sensations and are also discussed in relation to published findings from studies employing other HBD procedures.
Language: English
Field: Medicine
Open Access status: green
OpenAlex ID: W1142357742
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Cited by: 3
Related to: 10