Power calculations in single-case neuropsychology: A practical primer

McIntosh, Robert D.; Rittmo, Jonathan

doi:10.1016/j.cortex.2020.11.005

Cited by 18 publications

(11 citation statements)

References 20 publications

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“…If this is the case, then it means that our face recognition task only has 50% statistical power for detecting an effect (i.e., correctly confirming the presence of developmental prosopagnosia) when using the single-case approach (McIntosh & Rittmo, 2021 ). Conversely, there will be a 50% chance of committing a type II error (McIntosh & Rittmo, 2021 ), i.e., a rejection of someone with prosopagnosia as neurotypical, when they actually do suffer from this condition. This could explain why half of all potential prosopagnosia cases fail to meet single-case criteria on tasks such as the CFMT: it is because at the group level, they are only impaired – 2 SDs below the control mean (Fig.…”

Section: Introductionmentioning

confidence: 99%

“…In an ideal world, requiring objective impairments on a face processing task would seem a reasonable criterion for a diagnosis. This is because in the traditional neuropsychological approach for detecting deficits, scoring more than 1.96 SDs below a control mean on a cognitive task (i.e., bottom 2.5% of the general population, although this cut-off is commonly rounded up to 2 SDs) is the two-tailed threshold for determining a patient is significantly abnormal (McIntosh & Rittmo, 2021 ). Such requirements reassure researchers that these individuals are functioning abnormally in a specific domain, given the unlikely chance that a neurotypical individual would perform so poorly (Young et al, 1993 ).…”

Section: Introductionmentioning

confidence: 99%

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A new approach to diagnosing and researching developmental prosopagnosia: Excluded cases are impaired too

et al. 2022

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Developmental prosopagnosia is characterized by severe, lifelong difficulties when recognizing facial identity. Unfortunately, the most common diagnostic assessment (Cambridge Face Memory Test) misses 50–65% of individuals who believe that they have this condition. This results in such excluded cases’ absence from scientific knowledge, effect sizes of impairment potentially overestimated, treatment efficacy underrated, and may elicit in them a negative experience of research. To estimate their symptomology and group-level impairments in face processing, we recruited a large cohort who believes that they have prosopagnosia. Matching prior reports, 56% did not meet criteria on the Cambridge Face Memory Test. However, the severity of their prosopagnosia symptoms and holistic perception deficits were comparable to those who did meet criteria. Excluded cases also exhibited face perception and memory impairments that were roughly one standard deviation below neurotypical norms, indicating the presence of objective problems. As the prosopagnosia index correctly classified virtually every case, we propose it should be the primary method for providing a diagnosis, prior to subtype categorization. We present researchers with a plan on how they can analyze these excluded prosopagnosia cases in their future work without negatively impacting their traditional findings. We anticipate such inclusion will enhance scientific knowledge, more accurately estimate effect sizes of impairments and treatments, and identify commonalities and distinctions between these different forms of prosopagnosia. Owing to their atypicalities in visual perception, we recommend that the prosopagnosia index should be used to screen out potential prosopagnosia cases from broader vision research.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A new approach to diagnosing and researching developmental prosopagnosia: Excluded cases are impaired too

et al. 2022

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“…The individual, patient-level assessments were performed using case–control Bayesian tests of deficit ( Crawford & Garthwaite, 2007 , Crawford and Howell, 1998 ). The UOE control sample size of 24 provides close to the maximum power for these tests, but such a test can only achieve high power (>.80) if the behavioural deficit is large [>2.5 standard deviations from the control mean ( McIntosh & Rittmo, 2021 )]. It should therefore be emphasised that our assessment of patient-level deficits is concerned with large behavioural aberrations, not with subtle signs.…”

Section: Methodsmentioning

confidence: 99%

Peripheral reaching in Alzheimer's disease and mild cognitive impairment

Mitchell

Rossit

Pal

et al. 2022

Cortex

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“…The age of recruitment was set between 25 and 50 years. Recruitment of appropriate control participants was not easy and interim statistical analysis was decided, at 10 participants with a reasonable power (zcc >= 2, power of statistical test of 70%) ( McIntosh and Rittmo, 2021 ).…”

Section: Methodsmentioning

confidence: 99%

Role of the Dorsal Posterior Parietal Cortex in the Accurate Perception of Object Magnitude in Peripheral Vision

et al. 2021

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Following superior parietal lobule and intraparietal sulcus (SPL-IPS) damage, optic ataxia patients underestimate the distance of objects in the ataxic visual field such that they produce hypometric pointing errors. The metrics of these pointing errors relative to visual target eccentricity fit the cortical magnification of central vision. The SPL-IPS would therefore implement an active “peripheral magnification” to match the real metrics of the environment for accurate action. We further hypothesized that this active compensation of the central magnification by the SPL-IPS contributes to actual object’ size perception in peripheral vision. Three optic ataxia patients and 10 age-matched controls were assessed in comparing the thickness of two rectangles flashed simultaneously, one in central and another in peripheral vision. The bilateral optic ataxia patient exhibited exaggerated underestimation bias and uncertainty compared to the control group in both visual fields. The two unilateral optic ataxia patients exhibited a pathological asymmetry between visual fields: size perception performance was affected in their contralesional peripheral visual field compared to their healthy side. These results demonstrate that the SPL-IPS contributes to accurate size perception in peripheral vision.

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Power calculations in single-case neuropsychology: A practical primer

Cited by 18 publications

References 20 publications

A new approach to diagnosing and researching developmental prosopagnosia: Excluded cases are impaired too

A new approach to diagnosing and researching developmental prosopagnosia: Excluded cases are impaired too

Peripheral reaching in Alzheimer's disease and mild cognitive impairment

Role of the Dorsal Posterior Parietal Cortex in the Accurate Perception of Object Magnitude in Peripheral Vision

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