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Biomedical subjects

J P Chapman

Publications and source records attributed to J P Chapman.

17 recordsLinked to original sources
PubMed1992

Monaural and binaural story recall by schizophrenic subjects.

P. Green and other investigators have reported that schizophrenic Ss have poorer recall of stories presented to both ears than to the single best ear (binaural deficit) and poorer recall of stories presented to the left ear than to the right ear (monaural asymmetry) than do normal control Ss. These studies are plagued by potential methodological problems, including differences in overall accuracy, which artifactually affect the difference scores, and scoring methods that are vulnerable to systematic bias. In this study, scores of schizophrenic, bipolar, and normal control Ss on the Auditory Comprehension Test were compared. Scoring bias was avoided by the use of blind scoring and a revised scoring manual, and artifactual effects of accuracy were considered in interpreting the results. Contrary to previous findings, the groups did not differ on either monaural asymmetry or binaural deficit.

Adult↗
PubMed1990

Facilitation of word recognition by semantic priming in schizophrenia.

Schizophrenic (n = 21), bipolar (n = 18), and normal control subjects (n = 21) were compared on a word recognition measure of semantic priming. The task involved the presentation of related, neutral, and unrelated word pairs; the second word (target word) in each pair was presented in a degraded form. Facilitation was defined as the accuracy of target word recognition for the related word pairs minus accuracy for the neutral word pairs. Titration, achieved by manipulating the degradation of the target word, was used to maintain each subject's overall accuracy for related and neutral items at approximately 50%. This procedure minimized the artifactual effects of overall accuracy on the difference score. Schizophrenics exceeded both normal control subjects and bipolar subjects on facilitation. Bipolar subjects did not differ from control subjects. The results support Maher's hypothesis that semantic priming effects are heightened in schizophrenia.

Attention↗
PubMed1990

Schizophrenic deficit in span of apprehension.

We investigated two hypotheses about the span of apprehension task in schizophrenia: (a) schizophrenics show performance deficit on the forced-choice (FC) version but not on the full-report (FR) version, and (b) schizophrenic impairment on the FC version is greater when the display subtends a wide visual angle than when it subtends a narrow one. Schizophrenic (n = 21) and normal (n = 22) groups were tested on 3 versions of the task. A narrow-angle FC version was matched psychometrically with a wide-angle one by use of a greater number of noise letters in the narrow version. Schizophrenics reported fewer correct letters than normals on the FR version but did not differ on either the wide or the narrow FC versions. The results imply that schizophrenic deficit is not specific to the FC version and that on the FC version, visual angle is not more important than number of noise letters for demonstrating schizophrenic deficit.

Adult↗
PubMed1990

The treatment of mixed affective disorders in general practice: a comparison of trazodone and dothiepin.

The efficacy and tolerance of trazodone in the treatment of mixed affective disorder was compared with that of dothiepin in a double-blind, parallel group study in 228 general practice patients at 10 centres. After satisfying entry criteria, patients were randomized to receive either 150 mg trazodone at night, or 75 mg dothiepin at night for a 6-week period. Efficacy was assessed using the Hamilton Rating Scales for Depression and Anxiety. Significant improvements were observed in the condition of patients in each of the two treatment groups during the 6-week treatment period (p = 0.0001), with no statistically significant difference between the groups. There were no marked differences between the two treatment groups in the type of side-effects reported in response to open questioning, although a higher percentage of symptoms in the trazodone group were mild compared to the dothiepin group, and a lower percentage were severe. The incidence side-effects recorded by means of a checklist of common psychotropic side-effects was similar for the two treatment groups: dry mouth and drowsiness were the most frequent. A slightly higher proportion of patients withdrew from the dothiepin group, and of those who withdrew a higher percentage was due to side-effects than in the trazodone group.

Adult↗
PubMed1975

Schizophrenic reasoning about affect-laden material.

Drug-free schizophrenic patients (N equals 74) and nonpsychotic subjects (N equals 206) were given a test of affect-laden and affectively neutral multiple choice analogy items. The two subtests were matched on several psychometric characteristics that determine the power of the test to distinguish the more able from the less able normal subjects. Neither newly admitted schizophrenic nor long-term chronic schizophrenic patients performed differently on the affective subtest than on the neutral subtest. The many published findings of a cognitive deficit in schizophrenia in response to affect-laden stimuli can probably be attributed to the inappropriate use of unmatched tested.

Adult↗
PubMed1975

Alternatives to the design of manipulating a variable to compare retarded and nonretarded subjects.

In the design of manipulating a single variable to compare the performance of retarded and nonretarded subjects, the groups' response to the variable cannot demonstrate a loss of ability of retarded subjects. This is because tasks (measures at points on the variable) which differ on difficulty or on reliability also differ in power to distinguish subjects of differing ability. A solution is to hypothesize a differential deficit (greater deficit in response to one variable than another) and manipulate two variables. The tasks should be matched at all difficulty levels on reliability, mean, and variance of item difficulty and shape of the distribution of item difficulty.

Educational Measurement↗