eov
Dept of Medical Biophysics, University of Toronto, Toronto, Canada
dDept of Psychiatry, University of Toronto, Toronto, Canada
e Toronto Rehabilitation Institute, Toronto, Canada
f School of Rehabilitation Sciences, University of Ottawa,
gRotman Research Institute, Baycrest, Toronto, Canada
hMacquarie Centre for Cognitive Science, Macquarie Un
i Imaging Research, Sunnybrook Health Sciences Centre,
jDepartment of Communication Sciences and Disorders,
k e for Stro
focused on the neural processing characteristics associated with
recovery from aphasia (i.e., in the absence of treatment). Evidence
ofbothhomologous righthemisphere (RH)adaptationand increased
left hemisphere (LH) perilesional activity has been found (e.g., Cal-
vert et al., 2000; Cherney & Small, 2006; Fernandez et al., 2004; Hei-
not whether one or the other hemisphere plays a role in recovery,
but rather, when and under what circumstances each hemisphere
contributes to recovery.
An emerging area of enquiry is the investigation of the neural
underpinnings of recovery following therapy for aphasia. Rijntjes
and Weiller (2002) raise the important question of whether an ob-
served cortical reorganization following treatment is responsible
for ameasurable behavioral change. Improvedunderstanding at this
level could potentially better inform theoretically motivated treat-
ment approaches. The potential to identify therapy-induced areas
of activation is encouraging based upon the studies conducted to
* Corresponding author at: Department of Speech-Language Pathology, Univer-
sity of Toronto, 500 University Ave., Room 160, Toronto, ON, Canada M5G 1V7. Fax:
+1 416 978 1596.
Brain & Language 114 (2010) 164–179
Contents lists availab
Brain & La
.eE-mail address: elizabeth.rochon@utoronto.ca (E. Rochon).Treatment
Neuroimaging
fMRI
results showed that activation patterns changed after treatment on the semantic task in areas that
would have been expected (e.g., left hemisphere frontal and temporal areas). For one control patient,
there were no significant changes in brain activation at the second scan; a second control patient
showed changes in brain activation at the second scan, on the semantic task, however, these changes
were not accompanied with improved performance in naming. In addition, there appeared to be bilat-
eral, or even more right than left hemisphere brain areas activated in this patient than in the treated
patients. The healthy control group showed no changes in activation at the second scan. These findings
are discussed with reference to the literature on the neural underpinnings of recovery after treatment for
anomia in aphasia.
 2010 Elsevier Inc. All rights reserved.
1. Introduction
The use of neuroimaging techniques to study the neural under-
pinnings of recovery of language abilities following stroke has re-
cently come to the forefront. As Pizzamiglio, Galati, and
Committeri (2001) note in their review, many studies to date have
ss, Kessler, Thiel, Ghaemi, & Karbe, 1999; Jodzio, Drumm,Nyka, Lass,
&Gasecki, 2005;Rosen, 2000; Saur et al., 2006; Szekeres, Ylvisaker,&
Cohen, 1987). The respective roles of the right and left hemispheres
continue to be debated with regards to the question of the effects of
neuroplasticity in recovery from aphasia, however Crosson et al.
(2007) point out that the most fruitful approach to this question isHeart and Stroke Foundation of Ontario Centr
a r t i c l e i n f o
Article history:
Accepted 12 May 2010
Available online 14 June 2010
Keywords:
Aphasia
Anomia0093-934X/$ - see front matter  2010 Elsevier Inc. A
doi:10.1016/j.bandl.2010.05.005Ottawa, Canada
iversity, Sydney, Australia
Toronto, Canada
University of South Carolina, Columbia, USA
ke Recovery, Toronto, Canada
a b s t r a c t
Functional magnetic resonance imaging (fMRI) was used to investigate the neural processing character-
istics associated with word retrieval abilities after a phonologically-based treatment for anomia in two
stroke patients with aphasia. Neural activity associated with a phonological and a semantic task was
compared before and after treatment with fMRI. In addition to the two patients who received treatment,
two patients with aphasia who did not receive treatment and 10 healthy controls were also scanned
twice. In the two patients who received treatment, both of whose naming improved after treatment,Speech-Language Pathology, University of Toronto, Toronto, Canada
bDept of Psychology, University of Toronto, Toronto, Canada
cNeural changes after phonological treatm
Elizabeth Rochon a,e,k,*, Carol Leonard f,a, Hana Burian
Simon Graham i,g,c,k, Cheryl Grady g,d,b
a
journal homepage: wwwll rights reserved.nt for anomia: An fMRI study
a g,b,h, Laura Laird a, Peter Soros e,i,j,
le at ScienceDirect
nguage
lsevier .com/locate /b&l

angudate (e.g., Belin et al., 1996; Breier, Maher, Schmadeke, Hasan, &
Papanicolaou, 2007; Cornelissen et al., 2003; Farias, Davis, & Har-
rington, 2006; Léger et al., 2002;Meinzer,Wienbruch, Djundja, Bar-
thel, & Rockstroh, 2004; Musso et al., 1999; Pulvermüller, Hauk,
Zohsel, Neininger, & Mohr, 2005; Richter, Miltner, & Straube, 2008;
Small, Flores, & Noll, 1998; Wierenga et al., 2006). For example,
Meinzer et al. (2004), usingmagnetoencephalography (MEG), found
evidence for changes in perilesional activity, which was correlated
with the amount of change in language functions after treatment
in a large group of patients with chronic aphasia.
Recently, some studies have investigated neural activation pat-
terns following treatment that was specifically aimed at improving
anomia (i.e., word naming). For example, Léger et al. (2002) used
functional magnetic resonance imaging (fMRI) to explore areas of
activation for a picture naming task pre- and post-therapy in an
individual with aphasia who had a naming deficit. They found that
the pattern of activation post-therapy more closely mirrored that
of healthy controls, with greater activation in the LH language
areas surrounding the lesion and, in particular, in the left inferior
frontal gyrus. Interestingly, they also found continued RH activa-
tion post-therapy, as well as activation of the left supra-marginal
gyrus. They noted that the left supra-marginal gyrus is not typi-
cally associated with naming and suggested that it might represent
a compensatory strategy induced by the therapy – specifically a
greater attention to phonological features. A similar finding was
found by Cornelissen et al. (2003) using MEG. They investigated
the neural processing characteristics associated with a naming task
in three individuals with a moderate anomia due to phonological
output deficits pre- and post-therapy. For all three patients, nam-
ing improved post-therapy and was associated with greater activa-
tion in the left inferior parietal lobe. The authors attributed this to
improved phonological encoding as a function of the therapy.
Using time-resolved fMRI, Peck and colleagues demonstrated a
homologous right hemisphere shift as a function of improved ver-
bal response in one study (Peck et al., 2004), but not a subsequent
one (Crosson et al., 2005). Davis, Harrington, and Baynes (2006)
delivered an intensive semantic treatment to improve naming in
one patient. The patient demonstrated improvements in both sin-
gle word naming and noun production in connected speech after
therapy, and fMRI showed increased activation of the left inferior
frontal cortex and the right inferior posterior temporal cortex after
therapy. Fridriksson and colleagues (Fridriksson, Morrow-Odom,
Moser, Fridriksson, & Baylis, 2006; Fridriksson et al., 2007) have
conducted two studies. In one (Fridriksson et al., 2006), three par-
ticipants underwent three fMRI sessions both before and after
therapy. In the two participants who benefited from the treatment,
changes in perilesional activity in the left hemisphere as well as
right hemisphere activation were noted. These included changes
in the left temporal and the right posterior inferior parietal areas
(Patient 1); and the frontal poles, the anterior cingulate gyrus
and the left posterior supra-marginal gyrus (Patient 3). In a second
study, Fridriksson et al. (2007) found increased activity bilaterally
in the precuneus in two nonfluent patients who responded well to
a combined semantic-phonological approach to naming treatment.
Meinzer and colleagues (Meinzer, Obleser, Flaisch, Eulitz, & Rock-
stroh, 2007; Meinzer et al., 2006; Meinzer et al., 2008) have con-
ducted both fMRI and MEG studies to investigate neuroplastic
changes on naming abilities after Constraint-Induced Aphasia
Therapy (CIAT). Meinzer et al. (2006) showed that correct word re-
trieval after treatment was associated with increased activation in
the right inferior frontal gyrus (IFG) in one patient, but more bilat-
erally (in frontotemporal areas) in another patient (Meinzer et al.,
2007). In their most recent study Meinzer et al. (2008) have used
E. Rochon et al. / Brain & LMEG in addition to fMRI to show that improved naming abilities
in a group of eleven patients with chronic aphasia were correlated
with increased activation within LH perilesional areas.Based upon current theoretical models (e.g., Foygel & Dell,
2000), and as is evident from several of the studies reviewed above,
of particular relevance to the study of naming difficulties in pa-
tients with aphasia are the domains of semantic and phonological
processing. The results of recent investigations into these two do-
mains in healthy participants have converged upon a consensus of
brain areas involved. With regard to semantic processing, numer-
ous studies undertaken with a variety of neuroimaging techniques
(e.g., fMRI, MEG, positron emission tomography (PET)) and tasks
(e.g., word fluency, category judgment) have consistently identi-
fied two particular areas of high importance – the left inferior fron-
tal gyrus (LIFG), often the anterior portion, and the left middle
temporal gyrus (Baxter et al., 2003; Binder et al., 1997; Calvert
et al., 2000; McDermott, Petersen, Watson, & Ojemann, 2003; Pera-
ni et al., 2003; Roskies, Fiez, Balota, Raichle, & Petersen, 2001;
Whatmough & Chertkow, 2002). With regard to phonological pro-
cessing, the LIFG (often the posterior portion) has been identified
as a critical area of activation (McDermott et al., 2003, Paulesu
et al., 1997; Perani et al., 2003). In addition, activation of the left
inferior parietal gyrus, including the supra-marginal gyrus, has
been implicated in a number of phonological tasks including letter
word fluency (Perani et al., 2003), rhyming (Kareken, Lowe, Chen,
Lurito, & Mathews, 2000; Léger et al., 2002; Lurito, Kareken, Lowe,
Chen, & Mathews, 2000) and naming (Cornelissen et al., 2003).
Specifically in relation to picture naming, areas identified as being
preferentially activated overlap with the above-mentioned areas
for semantic and phonological processing. In healthy participants,
picture naming has been shown to activate a large bilateral net-
work (see Murtha, Chertkow, Beauregard, & Evans, 1999; Price,
Devlin, Moore, Morton, & Laird, 2005).
In summary, studies that have investigated the neural under-
pinnings of recovery following naming therapy in particular, have
generally found activation post-therapy in areas that have been
linked to semantic and/or phonological processing in healthy par-
ticipants, with the exception of Fridriksson et al. (2007) who also
found post-treatment changes in areas not typically associated
with language processing. In addition, some have reported in-
creased LH compared to RH activation after therapy (Cornelissen
et al., 2003; Meinzer et al., 2004; Meinzer et al., 2007); others have
found increased RH activation after therapy (Meinzer et al., 2006;
Peck et al., 2004); while still others have reported bilateral activa-
tion after therapy (Fridriksson et al., 2006; Léger et al., 2002; Mein-
zer et al., 2007). Patterns of activation have also been reported to
be more similar to controls’ after therapy in one study (Léger
et al., 2002), but not similar to controls’ in another (Fridriksson
et al., 2007).
These studies are notable in their attempts to correlate therapy-
induced improvements in naming performance with neural reor-
ganization. They do, however, suffer from some methodological
limitations. For instance, most studies do not include either a
healthy control group tested at two time points or an untreated
aphasic group, making it difficult to rule out potential test–retest
effects (Carel et al., 2000) and effects of maturation (or time). In
addition, with some notable exceptions (e.g., Cornelissen et al.,
2003; Fridriksson et al., 2007; Léger et al., 2002), most treatment
approaches were not specifically designed to treat word finding
impairments, making it uncertain whether the activation findings
reflect changes in word production per se or language processing
more broadly.
In the current investigation we used fMRI to investigate the
neural processing characteristics associated with word retrieval
abilities after treatment for anomia. Incorporating appropriate con-
trol groups, we compared performance of individuals with aphasia
age 114 (2010) 164–179 165on language tasks before and after a therapy program specifically
targeted at increasing the awareness of the phonological aspects
of words (Leonard, Rochon, & Laird, 2008). Participants from three