Biomedical subjects

John Podd

Publications and source records attributed to John Podd.

5 recordsLinked to original sources

PubMed2006

Memory deficits in Parkinson's disease.

The purpose of this study was to investigate deficits in recognition, recall, and prospective memory among Parkinson's disease (PD) patients, and to ascertain whether task difficulty and disease severity moderate these deficits. Comparisons were made between 41 nondemented PD participants, divided into early-stage and advanced-stage groups, and 41 matched controls. PD participants exhibited deficits in recognition, recall, and prospective memory. The advanced-stage PD group produced greater deficits than the early-stage PD group in all tasks, suggesting that these deficits increase in step with overall disease severity. The results of the task difficulty manipulation provide a partial explanation for the inconsistencies in the literature concerning the existence of recognition memory deficits in PD.

Aged↗

PubMed2005

Face recognition and aging: effects of target age and memory load.

In the present study, we investigated age-related decline in face recognition memory and whether this decline is moderated by the age of the target faces and by the number of faces that the participant must learn (memory load). Thirty-two participants in each of three age groups (18-39 years, 60-75 years, and 76-96 years) completed a face recognition task. Signal detection analyses confirmed that face recognition accuracy declined with age. However, this finding was qualified by an interaction between participant age and target age, which revealed that the age-related decline in face recognition accuracy occurred only for young target faces. Increased memory load was associated with comparable performance decrements across all age groups. However, memory load appears not to be the cause of these decrements. Instead, they appear to be a product of recognition load (the number of stimuli presented in the recognition phase).

Adolescent↗

PubMed2004

The placebo effect: dissolving the expectancy versus conditioning debate.

The authors review the literature on the 2 main models of the placebo effect: expectancy theory and classical conditioning. A path is suggested to dissolving the theoretical impasse that has long plagued this issue. The key is to make a clear distinction between 2 questions: What factors shape placebo effects? and What learning mediates the placebo effect? The reviewed literature suggests that classical conditioning procedures are one shaping factor but that verbal information can also shape placebo effects. The literature also suggests that conditioning procedures and other sources of information sometimes shape conscious expectancies and that these expectancies mediate some placebo effects; however, in other cases conditioning procedures appear to shape placebo effects that are not mediated by conscious cognition.

Cognition↗

PubMed2002

Brief exposure to a 50 Hz, 100 microT magnetic field: effects on reaction time, accuracy, and recognition memory.

The present study investigated both the direct and delayed effects of a 50 Hz, 100 microT magnetic field on human performance. Eighty subjects completed a visual duration discrimination task, half being exposed to the field and the other half sham exposed. The delayed effects of this field were also examined in a recognition memory task that followed immediately upon completion of the discrimination task, Unlike our earlier studies, we were unable to find any effects of the field on reaction time and accuracy in the visual discrimination task. However, the field had a delayed effect on memory, producing a decrement in recognition accuracy. We conclude that after many years of experimentation, finding a set of magnetic field parameters and human performance measures that reliably yield magnetic field effects is proving elusive. Yet the large number of significant findings suggests that further research is warranted.

Adult↗

PubMed2002

Driving-related fear: a review.

This article reviews the research on driving-related fear (DRF). Until recently, research has concentrated almost exclusively on the effect of motor vehicle accidents (MVAs) on subsequent levels of DRF. However, recent findings have suggested that MVAs are not solely responsible for this fear reaction, and that non-MVA driving fear can be just as strong. Studies of the broader driving-fearful population have encountered difficulty with diagnostic conceptualisation of DRF, although some have investigated a possible typology of DRF. Driving skill has been a neglected issue in the DRF research, and may prove to be a useful part of assessment and remediation of this potentially debilitating problem. Issues of definitional inconsistency are highlighted, and suggestions are made for several directions that future research might profitably take.

Accidents, Traffic↗