Reading and visual word recognition ability in semantic dementia is not predicted by semantic performance

Abstract

This paper describes longitudinal testing of two Semantic Dementia (SD) cases. It is common for patients with SD to present with deficits in reading aloud irregular words (i.e. surface dyslexia), and in lexical decision. Theorists from the connectionist tradition (e.g. Woollams et al., 2007) argue that in SD cases with concurrent surface dyslexia, the deterioration of irregular word reading and recognition performance is related to the extent of the deterioration of the semantic system. The Dual Route Cascaded model (DRC; Coltheart et al., 2001) makes no such prediction. We examined this issue using a battery of cognitive tests and two structural scans undertaken at different points in each cases time course. Across both cases, our behavioural testing found little evidence of a key putative link between semantic impairment and the decline of irregular word reading or lexical decision. In addition, our neuroimaging analyses suggested that it may be the emergence of atrophy to key neural regions both inside and outside the anterior temporal lobes that may best capture the emergence of impairments of irregular word reading, and implicated inferior temporal cortex in surface dyslexia.

On-Reading (Chinese-Style Pronunciation) Predominance Over Kun-Reading (Native Japanese Pronunciation) in Japanese Semantic Dementia

“…It has been shown that word frequency, familiarity, lexicality, and regularity (or consistency) influence the reading performance in semantic dementia ( Jefferies et al, 2004 ; Patterson et al, 2006 ; Fushimi et al, 2009 ; Wilson et al, 2009 ; Playfoot et al, 2018 ). Characteristic is a frequency-by-regularity interaction in which the patients’ worst performance is on low-frequency irregular or exceptional words ( Jefferies et al, 2004 ; Wilson et al, 2009 ).…”

Understanding How Sensory Changes Experienced by Individuals with a Range of Age-Related Cognitive Changes Can Affect Technology Use

“…This past clinical work has shown the way a person with dementia interprets what they see, hear, taste, feel and smell changes due to the condition [90], and that these changes may correlate with the progression of dementia [5]. Some of these changes are more common with specific types of dementia, (e.g., dementia with Lewy bodies [38,43,56,97] or Frontotemporal dementia [99]), but many sensory changes are common across various types of dementia [53,85,98,105]. Below, we review some of these changes experienced by people with dementia and mild cognitive impairment based on clinical literature.…”

“…People often experience difficulty with visual integration, meaning the ability to look at an object and properly orient it in space [105]. Some experience surface dyslexia, meaning additional difficulty identifying words while reading and classifying stimuli as words or not as words [98]. Additionally, people may experience difficulty with "seeing" more than one thing at a time, which is referred to as "simultanagnosia", grasping the "big picture", and selecting something specific from among a cluster of items [15,115].…”

“…Surface Dyslexia People with dementia can experience surface dyslexia, meaning it can be difficult to read irregular words and classify stimuli as words or not words [98]. Bill, living with dementia with Lewy bodies, explains his difficulty with restaurant menus: "there's just these big long words, it's just descriptions of things" which causes him to "have a hard time making a decision… for me that was never a problem" before dementia.…”

Using electrophysiological correlates of early semantic priming to test models of reading aloud

“…There is also a hypothesized anatomical area of the brain where early semantics is processed, the left anterior temporal lobe. The data that early semantic access is used when reading comes from behavioral experimentation, semantic dementia, functional magnetic resonance imaging, and computational modelling 14 – 16 , although some of it has been disputed 17 , 18 .…”