A Critical Examination of Augmenting/Reducing Methodology in Schizophrenic Patients and Controls

Connolly, John F.; Gruzelier, J.

doi:10.1159/000406991

Cited by 16 publications

(4 citation statements)

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“…The methodological criticism centers mostly on the fact that different means of assessing augmenting/reducing often do not correlate highly with each other. For example, Connolly and Gruzelier (1982a) looked at visual augmenting/reducing in both schizophrenic and normal subjects, using different methods of measurement. They showed that the technique of measuring peaks by the time band method, which had been used by Schooler et al (1976) following Shagass's (1972) lead, seemed to give less valid results for schizophrenics than for controls.…”

Section: Augmenting/reducingmentioning

confidence: 99%

“…Connolly and Gruzelier (1982a, 1982b) also criticized the use of linear slope as a method of summarizing amplitude-intensity functions. This index of augmenting/reducing is established by computing the slope of a linear regression line plotted through the amplitudes of the component of interest across the different levels of intensity used (in this case, amplitude can be measured by either the time band method or the amplitude at peak method).…”

Section: Augmenting/reducingmentioning

confidence: 99%

“…Using such a measure, augmenting subjects will have a highly positive slope whereas reducing subjects will have a low-positive or even slightly negative slope. Connolly and Gruzelier (1982a, 1982b; see also Iacono, Gabbay, & Lykken, 1982) pointed out that the coefficients of determination for such amplitude-intensity functions are often low, rendering the measure of questionable validity.…”

Section: Augmenting/reducingmentioning

confidence: 99%

“…Instead of slope, Connolly and Gruzelier (1982a, 1982b) recommended using a binary amplitude change classification scheme. In this scheme, an augmenting pattern is defined as one that shows a monotonic increase in amplitude at Cz across all amplitudes used, and a reducing pattern is defined as a failure to meet the augmenting criteria.…”

Section: Augmenting/reducingmentioning

confidence: 99%

See 3 more Smart Citations

Cognitive event-related potential correlates of schizophrenia.

Pritchard

1986

Psychological Bulletin

352

114

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In this article I review findings relating schizophrenia to four of the leading event-related brain voltage potential (ERP) components of interest to cognitive psychophysiologists. Research indicates that schizophrenics manifest the following cognitive ERP abnormalities relative to control subjects: (a) a diminished contingent negative variation (CNV) in warned reaction time paradigms during the warning stimulus-imperative stimulus interval; this CNV continues beyond presentation of the imperative stimulus as the postimperative negative variation (PINV). Contingent negative variation attenuation may reflect a state marker of psychosis in acute schizophrenics, whereas serving as a trait marker regardless of current symptoms in more chronic patients. In contrast, the PINV may be more of a state marker for both acute and chronic patients. (b) A pattern of P100–N100 reducing in acute schizophrenics that is not seen in chronic and paranoid patients. (c) Evidence of an attenuated enhancement of N100 (actually superimposed Nd or processing negativity) to stimuli presented in an attended channel, especially at slower event rates. (d) A diminished late positive complex (LPC) apparently due more to a diminished P300 than a diminished slow wave. The LPC attenuation in schizophrenics may to a degree reflect a trait marker of high risk for schizophrenia as well as a residual deficit state that often remains following the remission of positive symptoms. (e) Finally, with the possible exception of the PINV elicited in standard CNV paradigms, these ERP abnormalities do not appear to be specific to schizophrenia, as they are found in association with a variety of other disorders as well. The implication of each of these abnormalities for the conceptualization of the schizophrenic disorder is discussed, as is the “impaired performance” problem associated with doing ERP research with clinical groups.

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Section: Augmenting/reducingmentioning

confidence: 99%

Section: Augmenting/reducingmentioning

confidence: 99%