TY - JOUR
T1 - Paced reading in semantic dementia
T2 - word knowledge contributes to phoneme binding in rapid speech production
AU - Jefferies, Elizabeth
AU - Grogan, John
AU - Mapelli, Cristina
AU - Isella, Valeria
PY - 2012/4
Y1 - 2012/4
N2 - Patients with semantic dementia (SD) show deficits in phoneme binding in immediate serial recall: when attempting to reproduce a sequence of words that they no longer fully understand, they show frequent migrations of phonemes between items (e.g., cap, frog recalled as "frap, cog"). This suggests that verbal short-term memory emerges directly from interactions between semantic and phonological systems, allowing semantic knowledge to make a critical contribution to the stability of phonological sequences. According to this standpoint, SD patients should show phoneme binding deficits in additional language tasks beyond standard assessments of verbal short-term memory: for example, these errors should emerge in paced reading, which also requires the rapid production of semantically degraded words in order. To test this hypothesis, we examined a cyclical paced reading task in three SD patients for the first time. Every patient showed deficits in phoneme binding: they were more vulnerable than a set of age-matched controls to phoneme competition effects following the repetition of a small set of words across several cycles. They also showed substantially elevated numbers of phoneme migration, substitution and omission errors, despite being able to read the individual words almost without error. These findings confirm that the semantic contribution to phoneme binding is disrupted in SD patients across tasks. In line with the view that verbal short-term memory emerges from interactions between basic phonological and semantic components, these effects occur both within classic short-term memory paradigms, such as immediate serial recall, and tasks without explicit memory demands, such as paced reading. (C) 2012 Elsevier Ltd. All rights reserved.
AB - Patients with semantic dementia (SD) show deficits in phoneme binding in immediate serial recall: when attempting to reproduce a sequence of words that they no longer fully understand, they show frequent migrations of phonemes between items (e.g., cap, frog recalled as "frap, cog"). This suggests that verbal short-term memory emerges directly from interactions between semantic and phonological systems, allowing semantic knowledge to make a critical contribution to the stability of phonological sequences. According to this standpoint, SD patients should show phoneme binding deficits in additional language tasks beyond standard assessments of verbal short-term memory: for example, these errors should emerge in paced reading, which also requires the rapid production of semantically degraded words in order. To test this hypothesis, we examined a cyclical paced reading task in three SD patients for the first time. Every patient showed deficits in phoneme binding: they were more vulnerable than a set of age-matched controls to phoneme competition effects following the repetition of a small set of words across several cycles. They also showed substantially elevated numbers of phoneme migration, substitution and omission errors, despite being able to read the individual words almost without error. These findings confirm that the semantic contribution to phoneme binding is disrupted in SD patients across tasks. In line with the view that verbal short-term memory emerges from interactions between basic phonological and semantic components, these effects occur both within classic short-term memory paradigms, such as immediate serial recall, and tasks without explicit memory demands, such as paced reading. (C) 2012 Elsevier Ltd. All rights reserved.
UR - http://www.scopus.com/inward/record.url?scp=84858442147&partnerID=8YFLogxK
U2 - 10.1016/j.neuropsychologia.2012.01.006
DO - 10.1016/j.neuropsychologia.2012.01.006
M3 - Article
SN - 0028-3932
VL - 50
SP - 723
EP - 732
JO - Neuropsychologia
JF - Neuropsychologia
IS - 5
ER -