LINGUIST List 7.1

Mon Jan 1 1996

Sum: Broca's aphasia

Editor for this issue: Anthony M. Aristar <aristartam2000.tamu.edu>


Directory

  1. Stanley Dubinsky, Broca's aphasia summary

Message 1: Broca's aphasia summary

Date: Wed, 27 Dec 1995 14:28:54 EST
From: Stanley Dubinsky <DUBINSKUNIVSCVM.CSD.SCAROLINA.EDU>
Subject: Broca's aphasia summary
On Tue, 21 Nov 1995, I asked the following question of the list
(LINGUIST List: Vol-6-1644):

>Subject: Q: Broca's aphasia and ASL

>A student in my introduction to linguistics course asked a question
>today that I could not answer, but would like to be able to.
>She wanted to know how Broca's aphasia affects the language of signing
>adults. I assume that this aphasia does affect the syntax of ASL,
>however I was not sure whether it affects articulation. I.e., does
>Broca's area have the same control over manual articulation of ASL
>as it does over oral articulation of spoken language, and does damage
>to this area result in analogous articulatory difficulty for a
>signing patient (e.g. difficulty in producing complex ASL gestures,
>where there is no corresponding deficit in voluntary control of
>the same muscles).

I received a great number of helpful responses to the question,
along with references and suggestions about people to contact.
This summary includes information received from
the following LINGUIST subcribers:

Sergey Avrutin <avrutinminerva.cis.yale.edu>
William Badecker <billmail.cog.jhu.edu>
Kirrie Ballard <kballardmerle.acns.nwu.edu>
Paul Bessler <pbesslerepas.utoronto.ca>
Chris Brockett <chrisbrohalcyon.com>
Beth Elder <EAELDERUNIVSCVM>
Karen Emmorey <emmoreySC2.SALK.EDU>
Susan Fischer <SDFNCRritvax.isc.rit.edu>
Vicki Fromkin <IYO1VAFMVS.OAC.UCLA.EDU>
Colin Phillips <cphillMIT.EDU>
Caroline Steele <csteelehawaii.edu>
Sylvie Thibault <thibaltcc.UManitoba.CA>
Timothy J. Vance <tjvanconncoll.edu>
Mieke Van Herreweghe <Mieke.VanHerrewegherug.ac.be>
Erling Wande <Erling.Wandetele.su.se>

I have divided this summary into: (i) suggested answers, (ii) people and places
to contact, (iii) two relevant abstracts (provided by Karen Emmorey), and
(iv) references. In the first section, (i) answers, I have
attributed the responses to their authors.

*******************************************
(I) ANSWERS TO THE QUESTION:
*******************************************
================================================
Caroline Steele <csteelehawaii.edu>

It seems people with Broca's area aphasia are not able to substitute
signing for speaking. That is to say, they don't learn to sign after
having the CVA. There could be reasons for this, however, that are
different from their reasons for not being able to articulate.
========================================================
Beth Elder <EAELDERUNIVSCVM.CSD.SCAROLINA.EDU>

Oliver Sacks' book Seeing Voices (which is a fasinating though somewhat
technical book on the aquisition of language by the deaf) writes:
"... sign aphasias can affect either the lexicon or the grammar
(including the spatially organized syntax) of Sign differentially, as
well as impairing the general power to "propositionize" which
Hughlings-Jackson saw as central to language. But aphasic signers are
not impaired in other, nonlinguistic visual-spatial abilities....Signers
with right hemisphere strokes, in contrast, may have severe spatial
disorganization, an inability to appreciate perspective, and sometimes
neglect of the left side of space- but are not aphasic and retain
perfect signing ability despite their severe visual-spatial deficits.
Thus signers show the same cerebral laterlization as speakers, even
though their language is entirely visuo-spatial in nature."
========================================================
Colin Phillips <cphillMIT.EDU>

Poizner, Klima & Bellugi (1988, "What the Hands Reveal about the Brain",
MIT Press) looked at precisely those kinds of questions, with some quite
fascinating results. Basically, there appear to be dissociations between lingui
s
and non-linguistic motor production.
=======================================================
Erling Wande <Erling.Wandetele.su.se>

As far as I know the effects are about the same for signers as for
users of spoken language.
=======================================================
Vicki Fromkin <IYO1VAFMVS.OAC.UCLA.EDU>

According to the research conducted at the Salk by Ursula Bellugi and
her colleagues, deaf signers following brain lesions to Broca's area
and classified as Broca's aphasics parallel hearing aphasic in that
only the signing is effected -- in relation to the syntax and
'telegraphic speech' with difficulties in sign morphology etc. Their
ability to mime appears to be unaffected. Broca's hearing aphasics do
not have articulation difficulties necessarily (athough some studies show
intonation problems -- others show that this is only when the intonation
has grammatical consequences as in noun phrases vs noun compounds) -- and
neither do deaf Broca's patients in relation to non-linguistic motor
control.
========================================================
Paul Bessler <pbesslerepas.utoronto.ca>

With respect to your question about Broca's aphasia and ASL, your
hypothesis was right on the money. It was originally believed that
Broca's aphasia simply affected the organs of speech production.
About 15 years ago, however, a case study of a deaf Broca's aphasic
(sorry, I don't have a reference) showed that, although muscular
control was normal in the performance of other tasks, she had
difficulty producing ASL signs. Her production difficulties
corresponded closely to those which characterize the speech of
non-hearing impaired Broca's aphasics.
=======================================================
Karen Emmorey emmoreySC2.SALK.EDU

Aphasia can affect sign articulation .
=======================================================
Susan Fischer <SDFNCRritvax.isc.rit.edu>

You do seem to get classic dissociations between, e.g., the use
of space for grammatical pruposes and the ability to negoatiate in space
========================================================

*********************************
(II) SOURCES of information:
*********************************
========================================================
Dr. Judith Kegl at Rutgers Unviersity has studied these patients,
together with Dr. Ann Senghas (anniepsyche.mit.edu).
===========================================================
Sherman and Phyllis Wilcox, at the University of New Mexico,
have done research in the area.
========================================================
Ursula Bellugi and Edward Klima are at
The Salk Institute in La Jolla California.
========================================================
SLLING-L is a list specializing in signed languages.
If you subscribe to SLLING-L, you can post questions
to SLLING-LYALEVM.CIS.YALE.EDU.
If not, you can subscribe by sending the following request:
SUB SLLING-L <your name>
to: listservyalevm.cis.yale.edu
===================================================

******************************************************
(III) TWO IMPORTANT ABSTRACTS (from Karen Emmorey):
******************************************************
=====================================================
ABSTRACT 1:
Hickok, G, Kritchevsky, M., Bellugi, U., & Klima, E. (1995). The role of
the left frontal operculum in sign language aphasia: Clues to the function
of Broca's area. Poster presented at the Academy of Aphasia, San Diego,
November.

Since Broca's time, the left frontal operculum, in particular Brodmann's
areas 44 and 45, has figured prominently in attempts to determine the
anatomy of speech production (Mohr, 1976) . While recent studies have
shown convincingly that lesions restricted to the frontal operculum do not
lead to a lasting, severe speech production deficit, (Alexander, Naeser &
Palumbo, 1990; Mohr et al., 1978; Tonkonogy & Goodglass, 1981) evidence
from the acute postictal syndrome as well as evidence from cortical
stimulation (Ojemann, 1983; Penfield & Roberts, 1959) and functional
neuroimaging (Hinke et al., 1993; Petersen, Fox, Posner, Mintun & Raichle,
1988; Rueckert et al., 1994) suggests at least some role for Broca's area
in speech production.

 In this report, we describe our findings in the case of a patient,
RS, congenitally deaf and a native user of American Sign Language (ASL),
who suffered an ischemic infarct involving the frontal operculum and
inferior portion of the primary motor cortex. To be sure, part of the
long-standing enthusiasm for the hypothesis that the frontal operculum is
crucially involved in speech production derives from the intuitive appeal
of its anatomical position anterior to the motor cortex controlling the
musculature involved in speech. Thus, a major question in the present
study is, what is the role of this region in the production of a language
produced with the hands, rather than with orofacial articulators? To the
extent that the speech production system is plastic and self-organizing,
one might expect the functional analog of Broca's area to be shifted
superiorly so that it is anterior to sensory-motor representation for
hand/arm in the case of a deaf signer. Conversely, similarities in the
functional neuroanatomy of speech and sign production would suggest that
there are constraints on the extent to which neural organization for
language production is a self-organizing system.

 Language assessment was carried out using a sign-adapted version of
the Boston Diagnostic Aphasia Examination (Goodglass & Kaplan, 1976) , a
sign-adapted version of the Token Test (DeRenzi & Vignolo, 1962) , and an
analysis of conversational and narrative sign production. Lesion analysis
was carried out using 3-dimensional surface reconstructions from a
T1-weighted volume acquisition MRI dataset (slice thickness 1.5mm), and by
reconstructing, from the same dataset, para-axial slices for comparison
with analysis techniques based on CT images (Alexander et al., 1990) .
All brain imaging analyses were accomplished using Brainvox software
(Damasio & Frank, 1992) .

 Our findings with the present deaf, signing patient, RS, reveal
both similarities and differences in the aphasia syndrome following a
frontal operculum lesion, compared with that found in hearing/speaking
patients. In short, the set of symptoms we observed in the present case of
sign language aphasia is a superset of that noted in spoken language
(Alexander et al., 1990; Tonkonogy & Goodglass, 1981): Consistent with the
effects of similar lesions in hearing patients, RS presented with an acute
mutism that quickly resolved. But whereas hearing patients are typically
left with only a very mild aphasia, or no aphasia at all, RS's chronic
deficit included a fluent aphasia characterized by frequent phonemic
paraphasias. Consideration of the nature of her phonemic paraphasias
together with comparative lesion analyses suggests that the difference is
not simply a matter of a larger lesion producing a more severe deficit.
Rather, these data suggest that the left frontal operculum subserves a
similar function in both signed and spoken language, and that differences
in the resulting chronic syndrome following damage to this region can be
explained in terms of differences in the nature of the language
articulators. We further suggest that the differences in syndromes between
signed and spoken language reveal some additional clues to the function of
Broca's area independent of language modality.

=====================================================
ABSTRACT 2:
Erhard, P., Hickok, G., et al. (1995). Brain mapping of activated areas in
deaf subjects using American Sign Language during language paradigms.
Poster presented at the Meeting of the Society for Magnetic Resonance.
Nice, France, August.


American Sign Language (ASL) displays all of the complex linguistic structure
of spoken languages, but encodes that information spatially. Thus, ASL allows
one to dissociate modality dependent from modality independent contributions to
the neural organization for language. ASL's extensive reliance on spatial
contrasts in the encoding of linguistic structure would suggest a greater right
hemisphere involvement; however, there is strong evidence from lesion studies
that ASL is processed predominantly in the left cerebral hemisphere, and is to 
a
large extent independent of non-linguistic spatial cognition. In addition,
studies with ASL can allow the determination of whether Broca's area functions
specifically in the realm of language or is a higher order motor field concerne
d
with sequential movements. BOLD based functional Magnetic Resonance Imaging
(fMRI) provides the opportunity to elucidate the neural substrate of ASL and th
e
cortical representation of language in general. This approach was employed to
map activated regions in deaf subjects who are native ASL users during covert
and overt signing and during a motor control task that involved reproducing
"nonsense" hand shapes.

Methods: fMRI experiments were performed on a whole body system equipped
with a head gradient coil insert and a quadrature head coil. Twenty
eight
contiguous, multislice BOLD based fMRI images (TE = 20 ms; 50 ms/each image;
64x64; FOV = 20x20 cm2; slice thickness 5 mm) were obtained with conventional
blipped EPI. The repetition time was 2.5 sec for the multislice image set. A
multislice, T1 weighted FLASH sequence was also used to acquire anatomical
images of the same slices used for fMRI (TE = 8 ms, TR =11 ms). The paradigms
involved visual presentations via an RGB driven LCD display onto a
backprojection screen that was viewed by the subjects through an angled mirror.
Four tasks were examined: (a) covert signing of objects: subjects were asked t
o
imagine the ASL signs for objects displayed on the screen in succession every 2
second (bee, flower, apple, car etc.; objects that would be spelled using the
English-based manual alphabet rather than represented were avoided); (b) overt
signing of objects with one hand: same as the covert task but subjects produced
the signs with the hand adjacent to their leg to minimize motion (this is not a
n
unnatural task and this form of signing is employed in situations requiring som
e
degree of privacy; it is commonly referred to as "whispering"); (c) covert sig
n
generation: subjects were shown a hand shape every 5 seconds and were asked to
think of as many ASL signs as they could that contained that handshape; (d)
reproducing "nonsense" hand-shapes; subjects were asked to reproduce nonsense
hand shapes displayed to them in succession on the backprojection screen.
During the paradigms, task periods were alternated with "baseline" periods
during which the subjects were shown a flickering "noise" pattern on the screen
.
The activation maps were generated by a t-test screening for task-related
changes relative to this baseline. A total of 7 deaf native signers were
examined. The data presented below are from 2 subjects analyzed for covert
signing and motor control paradigms, and 1 subject analyzed for overt signing a
t
the present time, and represent preliminary results.

RESULTS:
 Extensive and consistent activation was observed during the aforelisted
paradigms. Most notably, in both covert tasks, areas activated included i)
areas dorsal to the sylvian fissure including area 44 (Broca's area),
ii)portions of areas 9 and 8, iii) medial wall motor areas (including portions
of supplementary motor area (SMA), preSMA, and the cingulate motor areas
buried in the cingulate sulcus) iv) lateral motor areas 4 and 6 (despite
no actual
signing) v) area 7, 40, 42, and 22 of the parietal cortex; vi) a portion of
area 24 located anteriorly in the cingulate gyrus.

 Activation in the medial wall motor areas, anterior cingulate gyrus and
prefrontal cortex were not as extensive in the motor control paradigm
(reproduction of nonsense hand shapes). Of special note, regions of Broca's
area that were activated during covert signing were also activated during the
performance non-representational hand-movements. This observation suggests
either of two exciting possibilities: i) Broca's area is not exclusively
related to language function as generally assumed but may represent a higher
order premotor area related to sequencing of motor acts or ii) significant
plasticity of brain function has occurred in deaf subjects who are native ASL
users. These possibilities are currently being explored in additional
experiments which include imaging hearing subjects who are native English
speakers.
==================================================
******************************
(IV) RELEVANT REFERENCES:
******************************
==================================================
The following volume should be at the top of any list of references on
this topic. It was suggested by seven of those responding as the first
place to look:

Poizner, H., Klima, E.S. & Bellugi, U. (1987), What the hands reveal
about the brain, Cambridge MA, MIT Press.

===================================================
Other suggested references are given here in alphabetical order:

 Alexander, M. P., Naeser, M. A., & Palumbo, C. (1990). Broca's area
aphasias: Aphasia after lesions including the frontal operculum.
Neurology, 40, 353-362.

Bellugi, U., Poizner, H., & Klima, E.S. 1989. Language, modality, and the
brain. Trends in Neurosciences, 10, 380-388.

Corina, Poizner, Bellugi, Feinberg, Dowd, & O'Grady-Batch (1992): Dissociation
between linguistic and nonlinguistic gestural systems: A case for
compositionality. Brain and Language, 43, 414-447.

Damasio, Bellugi, Damasio, Poizner, & van Gilder (1986): Sign language aphasia
during left hemisphere amytal injection. Nature, 322, 363-365.

Damasio, H., & Frank, R. (1992). Three-dimensional in vivo mapping of brain
lesions in humans. Archives of Neurology, 49, 137-143.

DeRenzi, E., & Vignolo, L. A. (1962). The token test: A sensitive test to
detect receptive disturbances in aphasics. Brain, 85, 665-678.

Goodglass, H., & Kaplan, E. (1976). The assessment of aphasia and related
disorders. Philadelphia, PA: Lea & Febiger.

Hinke, R. M., Hu, X., Stillman, A. E., Kim, S.-G., Merkle, H., Salmi, R., &
Ugurbil, K. (1993). Functional magnectic resonance imaging of Broca's area
during internal speech. Neuroreport, 4, 675-678.

Mohr, J. P. (1976). Broca's area and Broca's aphasia. In H. Whitaker & H.
A. Whitaker (Eds.), Studies in neurolinguistics, vol. 1, . New York:
Academic Press.

Mohr, J. P., Pessin, M. S., Finkelstein, S., Funkenstein, H. H., Duncan, G.
W., & Davis, K. R. (1978). Broca aphasia: Pathological and clinical.
Neurology, 28, 311-324.

Neville, H. J., Corina, D., Bavelier, D., Clark, V. P., Jezzard, P.,
Prinster, A., Padmanabhan, S., Braun, A., Rauschecker, J., & Turner,
R. (1995). Effects of early experience on cerebral organization for
language: An fMRI study of sentence processing in English and ASL by
hearing and deaf subjects. Proceedings of the First International
Conference on Functional Mapping on the Human Brain, 1, p. 143. [page
# may be incorrect]

Neville, H. J., Coffey, S. A., Lawson, D. S., Fischer, A., Emmorey,
K., & Bellugi, U. (in press). Neural systems mediating American Sign
Language: Effects of sensory experience and age of acquisition. Brain
and Language.

Ojemann, G. A. (1983). Brain organization for language from the perspective
of electrical stimulation mapping. Behavioral and Brain Sciences, 6,
189-230.

Penfield, W., & Roberts, L. (1959). Speech and brain-mechanisms. Princeton,
New Jersey: Princeton University Press.

Petersen, S. E., Fox, P. T., Posner, M. I., Mintun, M., & Raichle, M. E.
(1988). Positron emission tomographic studies of the cortical anatomy of
single-word processing. Nature, 331, 585-589.

"Brain Function for Language: Perspectives from Another Modality"
Howard Poizner, Ursula Bellugi, and Edward S. Klima
In MODULARITY AND THE MOTOR THEORY OF SPEECH PERCEPTION (ch. 7)
Ignatius G. Mattingly & Michael Studdert-Kennedy, eds.
Hillsdale, NJ: Lawrence Erlbaum Associates, 1991
ISBN 0-8058-0331-9

Poizner, Corina, Bellugi, O'Grady, Feinberg, & Dowd (1989): Sign aphasia and
spared pantomime. Journal of Clinical and Experimental Neuropsychology, 11.
42-?.

Poizner & Kegl (1992): Neural basis of language and motor behavior:
Perspectives from American Sign Language. Aphasiology, 6, 219-256.

Rueckert, L., Appollonio, I., Grafman, J., Jezzard, P., Johnson, R., Le
Bihan, D., & Turner, R. (1994). Magnetic resonance imaging functional
activation of left frontal cortex during covert word production. Journal of
Neuroimaging, 4, 67-70.

Tonkonogy, J., & Goodglass, H. (1981). Language function, foot of the third
frontal gyrus, and rolandic operculum. Archives of Neurology, 38, 486-490.

Wilcox, Sherman, et al. 1995. Gesture and the Nature of Language.
Cambridge: Cambridge University Press.
Mail to author|Respond to list|Read more issues|LINGUIST home page|Top of issue