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Cloutman, L.
L., Newhart, M., Davis, C. L., Heidler-Gary, J., & Hillis, A. E. (2011).
Neuroanatomical correlates of oral reading in acute left hemispheric stroke.
Brain and Language, 116, 14-21.
Notes: Oral reading is a complex skill involving the interaction of
orthographic, phonological, and semantic processes. Functional imaging
studies with nonimpaired adult readers have identified a widely distributed
network of frontal, inferior parietal, posterior temporal, and occipital
brain regions involved in the task. However, while functional imaging can
identify cortical regions engaged in the process under examination, it
cannot identify those brain regions essential for the task. The current
study aimed to identify those neuroanatomical regions critical for
successful oral reading by examining the relationship between word and
nonword oral reading deficits and areas of tissue dysfunction in acute
stroke. We evaluated 91 patients with left hemisphere ischemic stroke with a
test of oral word and nonword reading, and magnetic resonance
diffusion-weighted and perfusion-weighted imaging, within 24-48h of stroke
onset. A voxel-wise statistical map showed that impairments in word and
nonword reading were associated with a distributed network of brain regions,
including the inferior and middle frontal gyri, the middle temporal gyrus,
the supramarginal and angular gyri, and the middle occipital gyrus. In
addition, lesions associated with word deficits were found to be distributed
more frontally, while nonword deficits were associated with lesions
distributed more posteriorly
Department of Neurology, Johns Hopkins University School of Medicine, USA.
Lauren.Cloutman@manchester.ac.uk
Hillis, A. E.
(2008). Chapter 15 Cognitive processes underlying reading and writing and
their neural substrates. Handbook of Clinical Neurology,
volume 88.
Ed.by
P.J.Vinken & G.W.Bruyn.Amsterdam:Elsevier, , 311-322.
Notes: Johns Hopkins University School of Medicine, Johns Hopkins Hospital,
Baltimore, MD, USA
Hillis, A. E.
(2007). Alexia and agraphia in acute and chronic stroke. In O.Godefroy & J.
Bogousslavsky (Eds.), The behavioral and cognitive neurology of stroke
(pp. 102-125). Cambridge: Cambridge University Press.
Philipose, L.
E., Gottesman, R. F., Newhart, M., Kleinman, J. T., Herskovits, E. H.,
Pawlak, M. A. et al. (2007). Neural regions essential for reading and
spelling of words and pseudowords. Annals of Neurology, 62, 481-492.
Notes: Department of Neurology, Johns Hopkins University School of Medicine,
Baltimore, MD 21287, USA
OBJECTIVE: To identify dysfunctional brain regions critical for impaired
reading/spelling of words/pseudowords by evaluating acute stroke patients on
lexical tests and magnetic resonance imaging, before recovery or
reorganization of structure-function relationships. METHODS: A series of 106
consenting patients were administered oral reading and spelling tests within
24 hours of left supratentorial stroke onset. Patients underwent diffusion-
and perfusion-weighted magnetic resonance examination the same day to
identify regions of hypoperfusion/infarct of 16 Brodmann areas. RESULTS:
Simultaneous logistic regression analysis demonstrated that dysfunction of
left Brodmann areas 40 (supramarginal gyrus) and 37 (posterior-inferior
temporal/fusiform gyrus) best predicted impairment in reading words (odds
ratio [OR], 6.20 [95% confidence interval (CI), 1.54-24.96] and 2.71 [95%
CI, 0.87-8.45], respectively), reading pseudowords (OR, 39.65 [95% CI
3.9-400.78] and 4.41 [95% CI, 1.1-17.51], respectively), spelling words (OR,
14.11 [95% CI 1.37-144.93] and 7.41 [95% CI, 1.48-37.24], respectively), and
spelling pseudowords (OR, 4.84 [95% CI, 0.73-32.13] and 7.74 [95% CI,
1.56-38.51], respectively). Whole-brain voxel-wise analyses demonstrated
voxel clusters within these regions that were most strongly associated with
task deficits. INTERPRETATION: Results indicate that a shared network of
regions including parts of left Brodmann areas 37 and 40 is necessary for
reading and spelling of words and pseudowords. Further studies may define
the precise roles of these brain regions in language. Identification of any
neural regions specific to one of these tasks or one type of stimuli will
require study of more patients with selective deficits
Hillis, A. E.,
Newhart, M., Heidler, J., Marsh, E. B., Barker, P., & Degaonkar, M. (2005).
The neglected role of the right hemisphere in spatial representation of
words for reading. Aphasiology, 19, 225-238.
Notes: Dr. A.E. Hillis, Department of Neurology, Johns Hopkins University
School of Medicine, Johns Hopkins Hospital, 600 N. Wolfe Street, Baltimore,
MD 21287
Background: Previous studies have indicated that focal brain damage can
result in different types of "neglect dyslexia" (reading errors specific to
the side of printed material contralateral to the side of brain damage).
Aims: To identify the sites of lesions (or dysfunctional brain tissue)
responsible for distinct types of neglect dyslexia, to inform a functional
neuroanatomical model of brain regions involved in early stages of reading.
Methods & procedures: A battery of tests of hemispatial neglect and reading
designed to distinguish neglect dyslexia in different reference frames (viewer-centred,
stimulus-centred, and object-centred) was administered to 95 patients within
48 hours of onset of nondominant hemisphere stroke. Magnetic resonance
diffusion and perfusion imaging was obtained on the same day as testing.
Associations between each type of neglect dyslexia and areas of
hypoperfusion and/or infarct were evaluated using chi-squared tests.
Outcomes & results: Viewer-centred neglect dyslexia was associated with
hypoperfusion and/or infarct in right angular and supramarginal gyri and
visual association cortex ("dorsal stream"). Stimulus-centred neglect
dyslexia was associated with hypoperfusion and/or infarct of right superior
temporal cortex ("ventral stream"). Object-centred neglect dyslexia was
observed only with hypoperfusion and/or infarct of non-dominant superior
temporal cortex in left-handed individuals. Conclusions: The identified
associations provide evidence that different regions of cortex are critical
for spatial attention to, or processing of, representations of words with
distinct coordinate frames in the reading task.
Hillis, A. E.
& Heidler, J. (2005). Contributions and limitations of the cognitive
neuropsychological approach to treatment: Illustrations from studies of
reading and spelling therapy. Aphasiology, 19, 985-993.
Notes: Dr. A.E. Hillis, Department of Neurology, Johns Hopkins Hospital, 600
North Wolfe Street, Baltimore, MD 21287
Background: Cognitive neuropsychological research is focused on improving
the understanding of cognitive processes and representations underlying
normal tasks such as reading and spelling, on the basis of impaired
performance of these tasks after brain damage. Functional architectures of
cognitive tasks developed through this approach have often assisted
speech-language pathologists and other therapists in understanding the task
to be treated, and in identifying the impaired and spared components of the
task to be treated in each individual with brain damage. Aims: To review the
benefits and limitations of this approach, focusing on illustrations from
treatment of reading and spelling, and to provide ideas about how the
limitations might be addressed. Contributions: We provide examples that
demonstrate how disruption of particular cognitive functions in the process
of reading or spelling might be identified and rationally treated.
Additionally, we provide some illustrations of how limitations of this
approach might be addressed by considering evidence from cognitive
neuroscience regarding neural mechanisms of recovery and learning.
Conclusions: Insights from cognitive neuropsychology should be integrated
with insights from neuroscience in developing rehabilitation strategies.
Hillis, A. E.,
Newhart, M., Heidler, J., Barker, P., Herskovits, E., & Degaonkar, M.
(2005). The roles of the "visual word form area" in reading. NeuroImage,
24, 548-559.
Notes: Department of Neurology, Johns Hopkins University School of Medicine,
Baltimore, MD 21287, USA. argye@JHMI@edu
Activation of the left midfusiform gyrus in response to reading words and
pseudowords is such a reliable finding in functional imaging that this
region has been called "the visual word form area" (VWFA). However, this
label has recently been challenged, because activation in VWFA is also
observed in other lexical tasks. We evaluated whether VWFA is necessary,
sufficient, or specialized for reading by examining how frequently acute
lesions in VWFA disrupt tasks that require access to written word forms
versus other lexical tasks. We administered lexical tasks with spoken and
written input and output, and identified damage or dysfunction of VWFA and
other regions of interest (ROI) on diffusion- and perfusion-weighted imaging
(DWI and PWI) in 80 patients within 24 h of onset of acute left ischemic
stroke. Associations between abnormalities in each region of interest and
impairment on lexical tasks were evaluated with chi-squared tests. Damage or
dysfunction of VWFA was not significantly associated with impairment of
written word comprehension or lexical decision, but was significantly
associated with impairment on all tasks requiring lexical output: oral
reading and oral naming (visual or tactile input), and written naming. We
account for these results and results from functional imaging by proposing
that the left midfusiform gyrus normally has two roles in reading: (1)
computation of location- and modality-independent grapheme sequences from
written word stimuli, and (2) a modality-independent stage of lexical
processing that links modality-specific input and output representations.
VWFA is not necessary for the former because the right homologue of VWFA can
immediately assume this role
Marsh, E. B. &
Hillis, A. E. (2005). Cognitive and neural mechanisms underlying reading and
naming: evidence from letter-by-letter reading and optic aphasia.
Neurocase, 11, 325-337.
Notes: The Johns Hopkins University School of Medicine, Baltimore, MD 21287,
USA
We report detailed analysis of language performance in a patient, RMI, a
55-year-old man who presented with a homonymous hemianopsia, optic aphasia,
and alexia without agraphia (with letter-by-letter reading) acutely after
stroke. MRI showed infarct in the left occipital and medial temporal lobe
and hypoperfusion of the entire posterior cerebral artery territory,
including the splenium. Extensive language testing revealed severely
impaired picture naming and oral reading, with relatively spared tactile
naming and recognition of orally spelled words, consistent with impaired
access to lexical and semantic representations from vision. In addition, he
had a milder deficit in accessing lexical representations for output from
all input modalities. RMI's execution of various language tasks provided
considerable insight into the mechanisms that underlie oral reading. His
performance indicated that both semantic access and orthographic to
phonologic conversion mechanisms were partially intact. When information
from these two impoverished systems was coupled (the picture of an object
presented with its written name), his ability to read/name improved
significantly, consistent with the hypothesis that partially accessed
semantic information from vision can combine with partially accessed
sublexical orthographic to phonologic conversion mechanisms to access
phonological representations for output. Furthermore, his written word and
picture recognition improved to normal at a time when magnetic resonance
perfusion imaging demonstrated reperfusion of the splenium. We interpret
these results, as well as results from previous studies in the literature,
within a model of the neural regions critical for various cognitive
processes underlying reading
20060125
Hillis, A. E.
& Tuffiash, E. (2002). Neuroanatomical aspects of reading. In A.E.Hillis
(Ed.), The handbook of adult language disorders: Integrating cognitive
neuropsychology, neurology, and rehabilitation (pp. 15-25). New York:
Psychology Press.
Hillis, A. E.
(2002). Models of the reading process. In A.E.Hillis (Ed.), The handbook
of adult language disorders: Integrating cognitive neuropsychology,
neurology, and rehabilitation (pp. 3-14). New York: Psychology Press.
Beeson, P. M.
& Hillis, A. E. (2001). Comprehension and production of written words. In
R.Chapey (Ed.), Language intervention strategies in aphasia and related
neurogenic communication disorders (4 ed., pp. 572-604). Baltimore,MD:
Lippincott Williams & Wilkins.
Hillis, A. E.,
Kane, A., Barker, P., Beauchamp, N., Gordon, B., & Wityk, R. (2001). Neural
substrates of the cognitive processes underlying reading: Evidence from
magnetic resonance perfusion imaging in hyperacute stroke. Aphasiology,
15, 919-931.
Notes: Dr. A.E. Hillis, Department of Neurology, Johns Hopkins Hospital,
Meyer 5-185, 600 N. Wolfe Street, Baltimore, MD 21287, United States
Although it is widely agreed that reading aloud entails multiple cognitive
processes, there is little evidence for localisation of these processes. We
investigated regions of brain dysfunction associated with impairment of each
process. Forty patients were studied within 24 hours of onset of dominant
hemisphere stroke, using: (1) a battery of tasks to identify impaired
processes underlying reading, and (2) magnetic resonance perfusion imaging (MRPI)
and diffusion-weighted imaging (DWI). Impairment of each component of
reading, except motor speech, was highly correlated with one or more regions
of hypoperfusion identified by MRPI, but not with areas of infarct on DWI
Hillis, A. E. & Caramazza, A. (1995). Spatially specific deficits in
processing graphemic representations in reading and writing. Brain and
Language, 48, 263-308.
Notes: Department of Cognitive Science, Johns Hopkins University, USA We
report the performance of two brain-damaged subjects, HB and ML, whose
spelling performance is characterized by selective impairment in processing
the side of words contralateral to their brain damage. A striking feature of
these patients' performance was the fact that their spelling errors in all
tasks--written naming, written and oral spelling, and delayed copy
transcription- -almost exclusively concerned the right half of words (in the
case of HB) or the left half of words (in the case of ML), regardless of
length of the target response. These patterns of performance are interpreted
as indicating damage at the level of the grapheme description computed in
all spelling tasks. We also discuss the additional observations that HB
tended to complete words with nonrandom letter sequences in misspelling the
final half of the word and that ML tended to preserve the initial letter of
the word (in forward but not backward spelling) even when she made errors on
other letters in the initial half of the word. Finally, the relationship
between these spatially specific impairments of reading and writing and
their relationship to spatially specific deficits in non-lexical tasks is
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