[neuroling] Cognitive Neuroscience Abstracts
- From: "giancarlo" <giancarlo@xxxxxxxxxxxxxxxxxxxxxxxxxxx>
- To: "Neuroling" <neuroling@xxxxxxxxxxxxx>
- Date: Tue, 12 Nov 2002 07:16:02 -0700
(Posted by: Giancarlo Buoiano)
Cognitive Neuroscience Abstracts mainly focused on Broca?s Aphasia and
Comprehension
Journal: Brain
Abstract 1 of 6 Brain, Vol. 122, No. 5, 839-854, May 1999
© 1999 Oxford University Press
Electrophysiological manifestations of open- and closed-class words in
patients
with Broca's aphasia with agrammatic comprehension
An event-related brain potential study
Mariken ter Keurs1,2, Colin M. Brown1, Peter Hagoort1 and Dick F. Stegeman2
1 `Neurocognition of Language Processing' Research Group, Max Planck
Institute
for Psycholinguistics and 2 Department of Clinical Neurophysiology,
Institute of
Neurology, University Hospital Nijmegen, Nijmegen, The Netherlands
Mariken ter Keurs or Colin Brown, `Neurocognition of Language Processing'
Research Group, Max Planck Institute for Psycholinguistics, Wundtlaan 1,
NL-6525
XD Nijmegen, The Netherlands E-mail: terkeurs@xxxxxx or Colin.Brown@xxxxxx
This paper presents electrophysiological data on the on-line processing of
open-
and closed-class words in patients with Broca's aphasia with agrammatic
comprehension. Event-related brain potentials were recorded from the scalp
when
Broca patients and non-aphasic control subjects were visually presented with
a
story in which the words appeared one at a time on the screen. Separate
waveforms were computed for open- and closed-class words. The non-aphasic
control subjects showed clear differences between the processing of open-
and
closed-class words in an early (210?375 ms) and a late (400?700 ms)
time-window.
The early electrophysiological differences reflect the first manifestation
of
the availability of word-category information from the mental lexicon. The
late
differences presumably relate to post-lexical semantic and syntactic
processing.
In contrast to the control subjects, the Broca patients showed no early
vocabulary class effect and only a limited late effect. The results suggest
that
an important factor in the agrammatic comprehension deficit of Broca's
aphasics
is a delayed and/or incomplete availability of word-class information.
Broca's aphasia with agrammatic comprehension; open- and closed-class words;
event-related brain potential; lexical processing
ERP = event-related brain potential; RH = right hemisphere; VC = vocabulary
class
Abstract 2 of 6
Brain, Vol 111, Issue 5 1111-1137, Copyright © 1988 by Oxford University
Press
ARTICLES
Impaired grammar with normal fluency and phonology. Implications for Broca's
aphasia
SE Nadeau
Geriatric Research, Education, and Clinical Center, Veterans Administration
Medical Center, Gainesville, FL 32602.
Extensive testing of grammatical function, including assessment of
spontaneous
language, inflectional morphology, ability to produce grammatical
structures,
syntactic comprehension and grammatical judgement, was carried out in 2
patients
with large dominant frontal lobe lesions, including but not confined to, the
third frontal convolution. Both patients were fluent and had normal
articulation
and phonological production and neither was agrammatic, suggesting that even
very large frontal lesions do not produce Broca's aphasia and that language
cortex proper is confined to the postcentral perisylvian region. Both
patients
were impaired in the use of more complex syntactic structures and one, who
in
addition had severe generalized impairment in frontal lobe function, also
had
impaired judgement regarding the use and placement of functors. These data
provide further support for the dissociability of syntactic and
morphological
aspects of grammar in aphasic patients and, together with other studies,
link
these functions with the frontal lobe and the postcentral perisylvian
cortex,
respectively. The sparing of grammatical judgement in 1 patient, despite a
very
extensive lesion, suggests that very large portions of the frontal lobe are
involved in grammatical function. The nature of frontal lobe function in
syntax
appears to be congruent with the role of the frontal lobes in other aspects
of
behaviour.
Abstract 3 of 6
Brain, Vol 105, Issue 4 719-733, Copyright © 1982 by Oxford University Press
ARTICLES
From three to 3: a differential analysis of skills in transcoding quantities
between patients with Broca's and Wernicke's aphasia
G Deloche and X Seron
A psycholinguistic investigation into the ability of aphasic patients to
transcode integer quantities from written numeral forms into digit strings
is
reported. Broca's aphasics experienced specific difficulties in handling the
grammatical structure underlying word order and also, on the word level, the
bound morphemes relative to the root morphemes. Wernicke's aphasics seemed
to
have lexical troubles reflected by some purely lexical confusions together
with
serial order disturbances. These findings support the hypothesis of
differential
preserved/impaired skills according to type of aphasia, but having a high
level
of generality since they appear in classic linguistic tasks as well as in
the
domain of numbers.
Abstract 4 of 6
Brain, Vol 119, Issue 2 627-649, Copyright © 1996 by Oxford University Press
ARTICLES
Lexical-semantic event-related potential effects in patients with left
hemisphere lesions and aphasia, and patients with right hemisphere lesions
without aphasia
P Hagoort, CM Brown and TY Swaab
Max Planck Institute for Psycholinguistics, Nijmegen, The Netherlands.
Lexical-semantic processing impairments in aphasic patients with left
hemisphere
lesions and non-aphasic patients with right hemisphere lesions were
investigated
by recording event-related brain potentials (ERPs) while subjects listened
to
auditorily presented word pairs. The word pairs consisted of unrelated
words, or
words that were related in meaning. The related words were either
associatively
related, e.g. "bread-butter', or were members of the same semantic category
without being associatively related, e.g. "church-villa'. The latter
relationships are assumed to be more distant than the former ones. The most
relevant ERP component in this study is the N400. In elderly control
subjects,
the N400 amplitude to associatively and semantically related word targets is
reduced relative to the N400 elicited by unrelated targets. Compared with
this
normal N400 effect, the different patient groups showed the following
pattern of
results: aphasic patients with only minor comprehension deficits (high
comprehenders) showed N400 effects of a similar size as the control
subjects. In
aphasic patients with more severe comprehension deficits (low comprehenders)
a
clear reduction in the N400 effects was obtained, both for the associative
and
the semantic word pairs. The patients with right hemisphere lesions showed a
normal N400 effect for the associatively related targets, but a trend
towards a
reduced N400 effect for the semantically related word pairs. A dissociation
between the N400 results in the word pair paradigm and P300 results in a
classical tone oddball task indicated that the N400 effects were not an
aspecific consequence of brain lesion, but were related to the nature of the
language comprehension impairment. The conclusions drawn from the ERP
results
are that comprehension deficits in the aphasic patients are due to an
impairment
in integrating individual word meanings into an overall meaning
representation.
Right hemisphere patients are more specifically impaired in the processing
of
semantically more distant relationships, suggesting the involvement of the
right
hemisphere in semantically coarse coding.
Abstract 5 of 6 Brain, Vol. 125, No. 3, 452-464, March 2002
© 2002 Guarantors of Brain
Behavioural analysis of an inherited speech and language disorder:
comparison
with acquired aphasia
K. E. Watkins1, N. F. Dronkers2 and F. Vargha-Khadem1
1 Developmental Cognitive Neuroscience Unit, Institute of Child Health,
University College London Medical School, London, UK and 2 Center for
Aphasia
and Related Disorders, VA Northern California Health Care Center, Martinez,
California, USA
Correspondence to: Kate Watkins, Cognitive Neuroscience Unit, Montreal
Neurological Institute, 3801 University Street, Montreal, QC, Canada H3A 2B4
E-mail: kwatkins@xxxxxxxxxxxxxxxxx
Genetic speech and language disorders provide the opportunity to investigate
the
biological bases of language and its development. Critical to these
investigations are the definition of behavioural phenotypes and an
understanding
of their interaction with epigenetic factors. Here, we report our
investigations
of the KE family, half the members of which are affected by a severe
disorder of
speech and language, which is transmitted as an autosomal-dominant monogenic
trait. The cognitive manifestations of this disorder were investigated using
a
number of linguistic and non-linguistic tests. The aims of these
investigations
were to establish the existence of a ?core? deficit, or behavioural
phenotype,
and to explain how such a deficit during development might give rise to the
range of other impairments demonstrated by affected family members. The
affected
family members were compared both with the unaffected members and with a
group
of adult patients with aphasia resulting from a stroke. The score on a test
of
repetition of non-words with complex articulation patterns successfully
discriminated the affected and unaffected family members. The affected
family
members and the patients with aphasia had remarkably similar profiles of
impairment on the tests administered. Pre-morbidly, however, the patients
with
aphasia had enjoyed a normal course of cognitive development and language
experience. This benefit was reflected on a number of tests in which the
patients with aphasia performed significantly better than the affected
family
members and, in the case of some tests, at normal levels. We suggest that,
in
the affected family members, the verbal and non-verbal deficits arise from a
common impairment in the ability to sequence movement or in procedural
learning.
Alternatively, the articulation deficit, which itself might give rise to a
host
of other language deficits, is separate from a more general verbal and
non-verbal developmental delay.
Abstract 6 of 6 Brain, Vol. 124, No. 1, 103-120, January 2001
© 2001 Oxford University Press
Selective impairment of verb processing associated with pathological changes
in
Brodmann areas 44 and 45 in the motor neurone disease?dementia?aphasia
syndrome
Thomas H. Bak1,2, Dominic G. O'Donovan3, John H. Xuereb3, Simon Boniface4
and
John R. Hodges1,2
1 Medical Research Council Cognition and Brain Sciences Unit, 2 The
University
of Cambridge Neurology Unit and 4 The Department of Clinical
Neurophysiology,
Addenbrooke's Hospital, Cambridge and 3 The University of Cambridge
Department
of Pathology, Cambridge, UK
Professor John R. Hodges, MRC Cognition and Brain Sciences Unit, 15 Chaucer
Road, Cambridge CB2 2EF, UK E-mail: john.hodges@xxxxxxxxxxxxxxxxx
We report six patients with clinically diagnosed and electrophysiologically
confirmed motor neurone disease (MND), in whom communication problems were
an
early and dominant feature. All patients developed a progressive non-fluent
aphasia culminating in some cases in complete mutism. In five cases, formal
testing revealed deficits in syntactic comprehension. Comprehension and
production of verbs were consistently more affected those that of nouns and
this
effect remained stable upon subsequent testing, despite overall
deterioration.
The classical signs of MND, including wasting, fasciculations and severe
bulbar
symptoms, occurred over the following 6?12 months. The behavioural symptoms
ranged from mild anosognosia to personality change implicating frontal-lobe
dementia. In three cases, post-mortem examination has confirmed the clinical
diagnosis of MND?dementia. In addition to the typical involvement of motor
and
premotor cortex, particularly pronounced pathological changes were observed
in
the Brodmann areas 44 (Broca's area) and 45. The finding of a selective
impairment of verb/action processing in association with the
dementia/aphasia
syndrome of MND suggests that the neural substrate underlying verb
representation is strongly connected to anterior cortical motor systems.
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