"It's on the tip of my tongue!" exploring confrontation naming difficulties in patients with multiple sclerosis

BACKGROUND

Naming difficulty is commonly reported by patients with multiple sclerosis (pwMS). Though many cognitive batteries recommended for pwMS include fluency tasks, they do not include naming tasks. The aim of this study was to examine the prevalence of naming impairment in pwMS by using a measure of confrontation naming and to identify correlates with neuroimaging.

METHODS

One-hundred-eighty-five pwMS (M_age = 48.75 ± 11.23) completed neuropsychological testing and fifty had brain MRI scans within one year of neuropsychological testing. Controlling for demographic variables, partial correlations and hierarchical regressions with language tests as the outcome variables and neuroimaging variables as predictors were performed.

RESULTS

Performance on language tasks ranged within low average to average, with impairment most frequently found on a measure of confrontation naming (Boston Naming Test [BNT];27.6%), followed by a measure of phonemic fluency (Controlled Oral Word Association Test [COWAT]; 24.3%) and semantic fluency (animals [AF]; 18.3%). In the subset of patients with neuroimaging, thalamic volume had the strongest relationship with language variables, followed by white matter volume and T2 lesion volume. Language variables had no association with fractional gray matter volume. Of the language measures, BNT demonstrated the strongest relationship with MRI variables, followed by AF. There were no significant associations between neuroimaging variables and COWAT. Regression results revealed that fractional thalamic volume significantly contributed to BNT scores after adjusting for demographics, while T2 lesion volume predicted AF and no neuroimaging variables emerged as predictors for COWAT after controlling for demographics.

CONCLUSIONS

Objective naming impairment is common in pwMS and are more strongly associated with neuroimaging of MS brain pathology than verbal fluency tasks that are commonly used in cognitive batteries for pwMS. Continued research on language (especially naming) deficits and neuroimaging correlates (particularly thalamic involvement) in pwMS is needed.

Aging affects steaks more than knives: Evidence that the processing of words related to motor skills is relatively spared in aging

Lexical-processing declines are a hallmark of aging. However, the extent of these declines may vary as a function of different factors. Motivated by findings from neurodegenerative diseases and healthy aging, we tested whether 'motor-relatedness' (the degree to which words are associated with particular human body movements) might moderate such declines. We investigated this question by examining data from three experiments. The experiments were carried out in different languages (Dutch, German, English) using different tasks (lexical decision, picture naming), and probed verbs and nouns, in all cases controlling for potentially confounding variables (e.g., frequency, age-of-acquisition, imageability). Whereas 'non-motor words' (e.g., steak) showed age-related performance decreases in all three experiments, 'motor words' (e.g., knife) yielded either smaller decreases (in one experiment) or no decreases (in two experiments). The findings suggest that motor-relatedness can attenuate or even prevent age-related lexical declines, perhaps due to the relative sparing of neural circuitry underlying such words.

How the speed of word finding depends on ventral tract integrity in primary progressive aphasia

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Noise words influence naming time, but not accuracy, more in PPA than in controls.

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Noise effect difference between PPA and controls reflects ventral tract integrity.

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The noise effect is smaller when ventral tract integrity is lower in the individuals with PPA.

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Simulations reveal that propagation of noise is reduced when tract integrity is low.

Primary progressive aphasia (PPA) is a clinical neurodegenerative syndrome with word finding problems as a core clinical symptom. Many aspects of word finding have been clarified in psycholinguistics using picture naming and a picture-word interference (PWI) paradigm, which emulates naming under contextual noise. However, little is known about how word finding depends on white-matter tract integrity, in particular, the atrophy of tracts located ventrally to the Sylvian fissure. To elucidate this question, we examined word finding in individuals with PPA and healthy controls employing PWI, tractography, and computer simulations using the WEAVER++ model of word finding. Twenty-three individuals with PPA and twenty healthy controls named pictures in two noise conditions. Mixed-effects modelling was performed on naming accuracy and reaction time (RT) and fixel-based tractography analyses were conducted to assess the relation between ventral white-matter integrity and naming performance. Naming RTs were longer for individuals with PPA compared to controls and, critically, individuals with PPA showed a larger noise effect compared to controls. Moreover, this difference in noise effect was differentially related to tract integrity. Whereas the noise effect did not depend much on tract integrity in controls, a lower tract integrity was related to a smaller noise effect in individuals with PPA. Computer simulations supported an explanation of this paradoxical finding in terms of reduced propagation of noise when tract integrity is low. By using multimodal analyses, our study indicates the significance of the ventral pathway for naming and the importance of RT measurement in the clinical assessment of PPA.