An evaluation of statistical procedures for comparing an individual's performance with that of a group of controls

Mycroft, Rachel H.; Mitchell, Don; Kay, Janice

doi:10.1080/02643290143000150

Cited by 43 publications

(60 citation statements)

References 20 publications

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“…2. We also directly compared the performance of each of these patients to the control group using analysis of variance and modified F criteria, as suggested by Mycroft, Mitchell, and Kay (2002). The results were quite similar to those obtained with the cut-off at the lower range of normal controls.…”

Section: Acknowledgmentssupporting

confidence: 49%

Evidence for Multiple, Distinct Representations of the Human Body

Schwoebel

Coslett

2005

Journal of Cognitive Neuroscience

392

426

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Abstract& Previous data from single-case and small group studies have suggested distinctions among structural, conceptual, and online sensorimotor representations of the human body. We developed a battery of tasks to further examine the prevalence and anatomic substrates of these body representations. The battery was administered to 70 stroke patients. Fifty-one percent of the patients were impaired relative to controls on at least one body representation measure. Further, principal components analysis of the patient data as well as direct comparisons of patient and control performance suggested a triple dissociation between measures of the 3 putative body representations. Consistent with previous distinctions between the ''what'' and ''how'' pathways, lesions of the left temporal lobe were most consistently associated with impaired performance on tasks assessing knowledge of the shape or lexical-semantic information about the body, whereas lesions of the dorsolateral frontal and parietal regions resulted in impaired performance on tasks requiring on-line coding of body posture. &

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Section: Acknowledgmentssupporting

confidence: 49%

Evidence for Multiple, Distinct Representations of the Human Body

Schwoebel

Coslett

2005

Journal of Cognitive Neuroscience

392

426

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“…We follow here the approach described in Mycroft, Mitchell, and Kay (2002), where only the variability from the control group is taken into account in the calculation of the error term. They propose a revised F criterion to overcome the problems of differences in variability between patient and the control group.…”

Section: Discussionmentioning

confidence: 99%

Brain potentials reflect residual face processing in a case of prosopagnosia

Bobes

Lopera²,

Comas³

et al. 2004

Cognitive Neuropsychology

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Here, ERPs were employed to characterise the residual face processing of FE, a patient with extensive damage to the ventral temporal-occipital cortex and a dense prosopagnosia. A large N170 was present in FE and he performed well in tests of face structural processing. Covert recognition of the faces of personal acquaintances was demonstrated with P300 oddball experiments. The onset latency of the P300 effect was normal, indicating fast availability of covert memory. The scalp topography of this component in FE was different from that of the P3b, presenting a centro-frontal maximum. FE also presented larger skin conductance responses to familiar than to unfamiliar faces. The amplitudes of both the single-trial P300s and the SCRs triggered by familiar faces were positively correlated with the degree of person-familiarity that FE had for the poser. He performed at chance when asked to select between the face of a familiar person and that of an unfamiliar person on the basis of explicit recognition, whereas he selected more the previously known face if the forced choice was based on trustworthiness or a vague sense of familiarity. The results suggest that in FE, early face processing was relatively intact and covert recognition was fast. Neural structures involved in the processing of emotional or social cues possibly mediate the covert recognition present in FE.

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“…Eighteen comparisons adjusted using Bonferroni correction 2 An alternative method using parametric and nonparametric tolerance limits has been proposed by Capitani and colleagues (see Capitani et al, 1999). Unfortunately, this method relies upon testing very large normative samples (between 400 and 1000: see Wald 1943;and Mycroft et al, 2002 for a further recent discussion of this method) and so (for pragmatic reasons) has rarely been used in the general cognitive neuropsychological literature. In the case of the current study, our numbers of controls are commensurable or larger than in most similar studies compared with that of age-and gender-matched controls for living and nonliving things separately.…”

Section: Methodsmentioning

confidence: 99%

When is Category Specific in Alzheimer's Disease?

Laws

Gale

Leeson

et al. 2005

Cortex

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Mixed findings have emerged concerning whether category-specific disorders occur in Alzheimer's disease. Factors that may contribute to these inconsistencies include: ceiling effects / skewed distributions for control data in some studies; differences in the severity of cognitive deficit in patients; and differences in the type of analysis (in particular, if and how controls are used to analyse single case data).We examined picture naming in Alzheimer's patients and matched elderly healthy normal controls in three experiments. These experiments used stimuli that did and did not produce ceiling effects / skewed data in controls. In Experiment 1, we examined for category effects in individual DAT patients using commonly used analyses for single cases (χ 2 and z-scores). The different techniques produced quite different outcomes. In Experiment 2a, we used the same techniques on a different group of patients with similar outcomes. Finally, in Experiment 2b, we examined the same patients but (a) used stimuli that did not produce ceiling effects / skewed distributions in healthy controls, and (b) used statistical methods that did not treat the control sample as a population. We found that ceiling effects in controls may markedly inflate the incidence of dissociations in which living things are differentially impaired and seriously underestimate dissociations in the opposite direction. In addition, methods that treat the control sample as a population led to inflation in the overall number of dissociations detected. These findings have implications for the reliability of category effects previously reported both in Alzheimer patients and in other pathologies. In particular, they suggest that the greater proportion of living than nonliving deficits reported in the literature may be an artifact of the methods used.

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An evaluation of statistical procedures for comparing an individual's performance with that of a group of controls

Cited by 43 publications

References 20 publications

Evidence for Multiple, Distinct Representations of the Human Body

Evidence for Multiple, Distinct Representations of the Human Body

Brain potentials reflect residual face processing in a case of prosopagnosia

When is Category Specific in Alzheimer's Disease?

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