Modelling picture naming in aphasia: The relationship between consistency and predictability of responses.

Objective: Two aspects of aphasic picture naming were examined: that is, the extent to which the accuracy of the response to the same stimulus is replicated in a successive examination, and , that is, the extent to which accuracy depends on the characteristics of each stimulus.

Methods: Thirty-eight aphasic participants were examined twice. The response pattern was the same across the 2 presentations (response stability) for 36 participants, who were classified into 3 groups according to the prevailing error-type (lexical-semantic, phonological, or a balance between the two error-types): Their item-consistency was quantified with Cohen's kappa.

Outer and inner tolerance limits: their usefulness for the construction of norms and the standardization of neuropsychological tests.

Objectives: After adjustment of scores for demographic variables, especially when test scales have an upper limit that causes a ceiling effect, the original score variability is deeply altered and the scale properties degenerate. We present a method for fixing normality thresholds on scores previously adjusted for demographic variables that overcomes these problems.

Methods: We suggest to fix norms using non-parametric tolerance limits.

The dissociability of lexical retrieval and morphosyntactic processes for nouns and verbs: A functional and anatomoclinical study.

Nouns and verbs can dissociate following brain damage, at both lexical retrieval and morphosyntactic processing levels. In order to document the range and the neural underpinnings of behavioral dissociations, twelve aphasics with disproportionate difficulty naming objects or actions were asked to apply phonologically identical morphosyntactic transformations to nouns and verbs. Two subjects with poor object naming and 2/10 with poor action naming made no morphosyntactic errors at all.

Revised and extended norms for a picture naming test sensitive to category dissociations.

This study presents revised and extended norms for a picture naming test [Laiacona et al. (Arch Neurol Psicol Psichiatr 54:209-248, 1993)], based on 80 Snodgrass and Vanderwart (J Exp Psychol Human Learn Mem 6:174-215, 1980) pictures, devised to detect a categorical dissociation in the naming of items between biological and man-made categories. This survey is based on data from 215 healthy Italian participants.

Perseveration during verbal fluency in traumatic brain injury reflects impairments in working memory.

Objective: Previous studies of verbal fluency have reported higher rates of perseverative responses in both Alzheimer's disease (AD) and traumatic brain injury (TBI) relative to control groups. These perseverations could arise from a number of impairments-for example, failures in working memory, inhibitory control, or word retrieval-and different clinical populations may show an increase in perseveration because of different underlying deficits. The objective of the current report is to investigate the cause of perseveration in verbal fluency in individuals with TBI and compare those results to a recent study of individuals with AD.