Introduction
Results
Aphasia is a neurological disorder caused by damage to various cerebral areas associated with
language. Approximately 1 million people in the United States are currently affected by aphasia[1].
Although there is a wide range of variability in the condition, the patterns of impairment revolve around
language comprehension and/or language production. According to the National Institute of
Neurological Disorders and Stroke, patients are much more likely to recover skills
in language comprehension than those involving expression.
2. QPA measures correlate with word-level semantic production, but not sentence comprehension
Behav
iora
la
nd
Introduction
Examine the behavioral and neural correlates of
fluency in aphasia by evaluating archival data
from 31 individuals with chronic aphasia
following left hemisphere stroke.
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46
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45, 44
(Broca’s)
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43
47
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Archival data was compiled from Moss
Aphasia Psycholinguistics Project
Database (MAPPD), including measures of
overall aphasia severity, word-level
recognition and production, sentence
comprehension, and location and size of lesion.
Methods of Fluency Analyses:
1. Correct Information Unit (CIU) analysis:
characterizes semantic features
2. Quantitative Production Analysis (QPA):
characterizes grammatical features
Brodmann’s Areas (BA) 44 & 45:
Together, BA44 and BA45 compose Broca’s area, a region
well-documented in its vital role in various speech and language
functions. Broca’s area has been implicated in cognitive control at
nearly every level of language processing, from selective attention for
speech to reasoning processes, and ultimately to fluency.
Results
CIU measures are
highly correlated with one
another (r > 0.8, p << 0.001),
as well as with QPA words per
minute measure (r > 0.75, p << 0.001)
Amanda Kraft and Daniel Mirman
1
1
Areas in red indicate level of significance - the bars
from right to left represent p > 0.5, p > 0.01, p >0.005
Conclusions
20
Subjects
1.
39
2
4
1,
4
38
Methods & Materials
40
7
3. After controlling for lesion volume (indicated in
squares), QPA measures strongly correlated with
damage to left inferior frontal regions, particularly
Brodmann area 45
asia
Aph
in
its
fic
Fluent language production requires coordination of all levels of
language processing, from recognition of speech sounds to
producing utterances having both meaning and relevance to the
given context. Measures of fluency in aphasia attempt to
capture these various levels of language processing in
terms of semantic and syntactic content, grammatical
form, and rate of speech.
Areas in red indicate level of significance - the bars from left to right represent p > 0.5, p > 0.01, p >0.005
Psychology Department, Drexel University
2
Moss Rehabilitation Research Institute
1,2
These QPA fluency measures were highly
correlated with word-level semantic
production, but not with sentence
comprehension, suggesting that there is
some separation between language
production and comprehension systems that
spans these two levels. Further, QPA
measures correlated with damage to left inferior
frontal regions, particularly Brodmann area 45.
Given this region’s involvement in cognitive control
functions, fluent language production seems to
depend on cognitive control mechanisms. In particular,
a common mechanism for rapidly selecting among
alternative sentence structures and words to fill those
structures appears to be a critical component of fluent
language production.
References
[1] Aphasia (2015, April 17). National Institute of Neurological Disorders and Stroke.
[2] Amunts, K., Weiss, P. H., Mohlberg, H., Pieperhoff, P., Eickhoff, S., Gurd, J. M., . . . Zilles, K. (2004). Analysis of neural
mechanisms underlying verbal fluency in cytoarchitectonically defined stereotaxic space—The roles of brodmann areas
44 and 45. NeuroImage, 22(1), 42-56.