Communication ability in non right hande

Journal of Neurolinguistics 17 (2004) 301–313
www.elsevier.com/locate/jneuroling

Communication ability in non-right handers
following right hemisphere stroke
Catherine Mackenziea,*, Marian Bradyb
a

Department of Speech and Language Therapy, University of Strathclyde, Southbrae Drive,
Glasgow G13 1PP, UK
b
Nursing Research Initiative for Scotland, Glasgow Caledonian University, Glasgow G4 0BA, UK

Abstract
Communication ability following right brain damage (RBD) has been frequently investigated, but
almost exclusively in the right handed (R) population and where non-right handers (NRs) have been
studied their inclusion has been motivated by the presence of aphasia. Communication assessment,
covering aspects of spoken discourse and comprehension, which in Rs are sensitive to the effects of
RBD, was carried out on five NR adults 3 months after right hemisphere stroke. Performance was
compared to matched R stroke participants ðn ¼ 9Þ and non-brain damaged (NBD) participants
ðn ¼ 20Þ: On all communication measures there was remarkable similarity between the scores of the

R and NR RBD groups. Both stroke groups were significantly impaired in comparison with the NBD
group in inference comprehension and in non-verbal conversational parameters. The RBDNR group
was less efficient than the NBD group in conveying relevant picture description content and a similar
trend was present for the RBDR group. The RBDR group scored significantly below the NBD group
in tests of discourse and metaphor comprehension. Future research involving NRs should examine
communication difficulties within a broad context of functions to inform the relationship between
language and other presumed lateralised higher functions.
q 2003 Elsevier Ltd. All rights reserved.
Keywords: Communication; Right brain damage; Handedness

The left hemisphere of the brain’s major role in language processing has been recognised
since the work of Dax in 1836 and Broca in 1865 when the presence of aphasia began to be
associated with left hemisphere damage in right handed people (Joanette & Goulet, 1994)
Subsequently the belief was widely held that for left handed people language was
lateralised in the right hemisphere (Subirana, 1969). Cases of aphasia in left handers
following left lesions were reported intermittently but it was not until the publication of
* Corresponding author. Tel.: þ 44-141-950-3454; fax: þ44-141-950-3451.
E-mail address: c.mackenzie@strath.ac.uk (C. Mackenzie).
0911-6044/$ - see front matter q 2003 Elsevier Ltd. All rights reserved.
doi:10.1016/S0911-6044(03)00061-7

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systematic surveys such as that of Goodglass and Quadfasel (1954) that it became clear
that neurological language control in non-right handers (NRs) was not merely a mirror
image of the situation for right handers (Rs). NRs are a heterogeneous group as regards
language laterality and it may even be that some have separate hemispheric loci for speech
output and comprehension (Naeser & Borod, 1986).
For the majority of NRs the left hemisphere is dominant for language and functional
magnetic resonance imaging (fMRI) data indicate that 8% have right dominance and 14%
show symmetrical activation (Szaflarski et al., 2002). The likelihood of right dominance
appears to increase with the degree of left handedness (Knecht et al., 2000). Incidence of
aphasia following right brain damage (RBD) in NRs is often stated as around 30% though
in most NRs aphasia is associated with left damage (Marien, Paquier, Cassenaer, & De
Deyn, 2002). By contrast, aphasia resulting from RBD is an exceptional occurrence in Rs.
Early studies reported a higher incidence of aphasia in NRs compared with Rs (Conrad,
1949; Gloning, Gloning, Haub, & Quatember, 1969). Also the severity of aphasia was
sometimes noted to be less in NRs than in Rs (Luria, 1970) and prognosis for aphasia

recovery was believed to be better in NRs (Subirana, 1969). Such observations lent
support to the emerging view that in NRs language may be less strongly lateralised and so
may be vulnerable with injury to either hemisphere but also less likely to be severely
impaired than where left damage occurs in Rs with strong left hemisphere language
control. However, in more recent research, differences in aphasia severity and/or recovery
in NR and R patients have not been found (Basso, Farabola, Grassi, Laiacona, & Zanobio,
1990; Kertesz, 1993; Laska, Hellblom, Murray, Kahan, & Von Arbin, 2001; Naeser &
Borod, 1986; Pedersen, Jorgensen, Nakayama, Raaschou, & Olsen, 1995) and Basso et al.
(1990) concluded that the importance of left handedness had been overemphasised in the
past. Handedness related language performance differences were similarly not found in a
recent study of people with Alzheimer’s disease (Doody, Vacca, Massman, & Liao, 1999).
Premorbid handedness is regarded as an important variable to be controlled in
communication research (Brookshire, 1983; Kaplan & Goodglass, 1981; Wertz, 1993). In
most contemporary studies such control has been achieved by exclusion of those not
clearly R. There exist few detailed studies of how stroke or other brain injury affects the
communication skills of the NR population. Although the majority of the adult population
is R, at 4 –11% (Ellis, Ellis, Marshall, Windridge, & Jones, 1998) NRs represent an
important section of the population.
In Rs with LBD language impairment is most commonly described using the classical
or connectionist system of aphasia classification, though the proportion of cases who

conform to definition may range from 30 to 80% depending on the strictness of adherence
to criteria (Goodglass & Kaplan, 1983). Knowledge of how acquired neurological damage
affects communication in NRs is especially limited for RBD. Where such cases have been
included in language investigations, some have shown fairly classical aphasia profiles, and
others have had more unusual language patterns (Alexander & Annet, 1996). Gloning et al.
(1969) examined 25 matched R/NR pairs with RBD in the first week following hospital
admission. On all of a range of language tasks the NR group was significantly more
impaired, but the transience of aphasia was noted in this group. No severity difference was
observed between R and NR groups who had left hemisphere lesions. The research of
Basso et al. (1990) included one pair of R/NR RBD subjects, matched for age, education,

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303

time post-onset, and lesion location. As with their left lesion data, aphasia was very similar
in the R and NR subjects. In further contrast to Gloning et al’s findings, for three additional
unmatched NRs with RBD, aphasia recovery was unremarkable.
For the R population, while left hemisphere lesions frequently result in obvious and
significant deficits in language, much recent research has indicated that RBD may also

limit competence in communication, particularly in text level processing and pragmatics
(the interaction between language behaviour and context). A cluster of ‘right hemisphere
communication deficits’ are identified in this population (Myers, 1999; Tompkins, 1995)
for which lately the diagnostic labels of ‘pragmatic aphasia’ (Joanette & Anslado, 1999) or
‘apragmatism’ (Myers, 2001) have been suggested. Correspondingly, fMRI and functional
transcranial Doppler ultrasonography (fTCD) studies have objectively demonstrated the
right hemisphere’s contribution to language processing in the left hemisphere language
dominant R population (Knecht et al., 2000; Springer et al., 1999). In cases of language
impairment following RBD in NRs reported in the literature, because language assessment
has been tailored to the diagnosis of aphasia, only those with frank language impairment
would be identified. Information on how NRs with RBD perform in language tasks
which are sensitive to the more subtle communication problems associated with right
lesions is not readily available.
The present report provides initial data on the communication performance, both verbal
comprehension and spoken discourse, of NRs following right hemisphere stroke.
Comparison is made with Rs with similar age, education and stroke histories, and Rs
without neurological damage. The assessment point for the neurologically impaired
groups was 3 months post-stroke.

1. Participants

The RBDNR group comprised five non-right handed right hemisphere stroke
participants (mean age 62.2, SD 14.97). Each was matched þ /2 5 years of age with:
(a) two right brain damaged right handers with similar stroke classification (RBDR),
with the exception of case RBDNR5 for whom only one match was available (n ¼ 9;
mean age 61.56, SD 13.76), and with.
(b) four non-brain damaged right handers (NBD) (n ¼ 20; mean age 61.3, SD 13.14).
Mean ages for the three groups were equivalent (ANOVA, F 0.009, df 2, p ¼ 0:991).
No participant had formal education beyond the minimum UK legal requirement (school
leaving age 14 until 1947, thereafter 15 until 1972, with school entry at age 5). Participants
were not gender matched. This is consistent with the findings of Mackenzie (2000a,b) that,
for the communication assessments used, gender was not an influencing variable, unlike
age and education.
English was the first language. Hearing and vision were adequate (with hearing aid or
glasses worn as required), by self-report and subjective appraisal by the researcher for
conversation and audiotaped material, picture material and ‘large size’ book style print.
All participants passed a dementia screening assessment, the Anomolous Sentences

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Repetition Test (Weeks, 1988). No participant was receiving speech and language therapy
intervention. NBD participants by self-report were without neurological or psychiatric
history. The NBD group was drawn from a database of 189 subjects, aged 40– 88. Stroke
participants had no record or evidence of previous neurological or psychiatric occurrence.
The presence of right-sided stroke was diagnosed on the basis of clinical signs and in all
but one case verified radiologically by CT or MRI. Stroke was ischaemic in all cases.
Stroke classification was according to the scheme of Bamford, Sandercot, Dennis, Burn
and Warlow (1988). Both RBDR and RBDNR groups were drawn from a database of 70
participants aged 36– 86 with single right stroke, undergoing communication assessment
at 3 months post-stroke. One RBDNR participant (case RBDNR1) was diagnosed by the
speech and language therapist researcher as presenting aphasic features in conversation,
principally agrammatism and paraphasic errors. None of the RBDR group was diagnosed
with aphasia. Age, gender and stroke details for the three participating groups are given in
Table 1.
Handedness was assessed using the Edinburgh Handedness Inventory (Oldfield, 1971).
To be classified as R, subjects reported right handed preference for at least eight of the 10
test activities, including writing. For the NR group for at least six of the activities the left
hand was used or either hand was used without preference. No participants recalled a
parental history of left handedness.

Table 1
Participant data
Stroke participant

Age

Gender

Stroke

Non stroke participant

Age

Gender

RBDNR 1
RBDR 1
RBDR 2

44
44
49

M
F
F

TACI
TACI
TACI

RBDNR 2
RBDR 3
RBDR 4

82
79
82

M
M
F

TACI
TACI
TACI

RBDNR 3
RBDR 5
RBDR 6

66
65
63

F
F
M

PACI anterior
PACI anterior
PACI anterior

RBDNR 4
RBDR 7
RBDR 8

51
48
54

M
M
F

TACI
TACI
TACI

RBDNR 5
RBDR 9

68
70

M
F

POCI
POCI

NBD 1
NBD 2
NBD 3
NBD 4
NBD 5
NBD 6
NBD 7
NBD 8
NBD 9
NBD 10
NBD 11
NBD 12
NBD 13
NBD 14
NBD 15
NBD 16
NBD 17
NBD 18
NBD 19
NBD 20

46
45
45
42
81
83
78
78
62
65
62
65
50
48
51
53
71
66
71
64

M
M
M
F
M
M
M
F
M
F
F
F
F
F
M
M
M
M
M
M

RBDNR: right brain damage, non-right handed, RBDR: right brain damage, right handed, NBD: non-brain
damage. TACI: total anterior circulation syndrome, PACI: partial anterior circulation syndrome, POCI: posterior
circulation syndrome.

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305

2. Communication assessment
Previous communication research has indicated that measurements of spoken
discourse, semantic judgement, and comprehension of metaphor and discourse, including
inference, are sensitive to the effects of RBD (Tompkins, 1995). The measures used in this
study were selected for their routine clinical availability, test – retest reliability for the
neurologically normal population (Mackenzie, 2000a,b) and of special relevance for the
spoken discourse measures, good levels of inter-judge and intra-judge scoring reliability
(Mackenzie, 2000; Mackenzie, Begg, Lees, & Brady, 1999).
Auditory Synonym Judgements (ASJ) (Kay, Lesser, & Coltheart, 1992). Sixty pairs of
words (divided into parallel sets of 30 pairs each) are presented in spoken form for
decision as to whether the two words are similar in meaning or not.
Discourse Comprehension Test (DCT) (Brookshire & Nicholas, 1993). A series of 10
stories (divided into parallel sets of five stories, A and B), each of around 200 words, in
which the frequency of content words is representative of adult conversation, is followed
by a set of questions to be answered ‘yes’ or ‘no’. The questions cover main ideas and
details and stated and implied information.
Metaphor Picture Test (MPT) (Bryan, 1989). Ten sentence metaphors are individually
presented in spoken form each accompanied by a set of four pictures, representing the
metaphorical meaning, the literal meaning and two control items.
Comprehension of Inferred Meaning Test (CIMT) (Bryan, 1989). Three short
paragraphs, one conversational, one narrative and one emotional, each of around 60
words is each followed by four inferential questions. Presentation of both stimuli and
questions is in combined written and spoken form with the written stimulus paragraph
retained throughout.
Picture description. Description of the ‘cookie theft’ picture from the Boston
Diagnostic Aphasia Examination (Goodglass & Kaplan, 1983) analysed as follows:
number of interpretive units (CTIU) (i.e. units which derive meaning within the depicted
situation, e.g. mother, there’s going to be an accident, as distinct from literal units, e.g.
woman, stool), Index of efficiency in conveying content, calculated from word count
(number of words, including repetitions, comments and questions) relative to total content
units (literal plus interpretive) total (CTEFF), Occurences of extraneous material such as
digression, intrusion of personal material or opinion, relative to total word count
(CTEXT). The scoring guidelines for literal and interpretive content units were based on
the work of Myers (1979) and Yorkston and Beukelman (1980).
Conversation. Approximately 10 min of conversation between the participant and
assessor on everyday topics such as weather, employment, holidays, health, day to day
activities and family were audio recorded for rating. Perceptual and observational ratings
were carried out on eight conversational parameters, five verbal interactive (conversational initiation, turn taking, verbosity, topic maintenance, referencing) and three nonverbal (intonation, facial expression, eye contact) using a five point severity scale, with
five representing ‘normal’ (Burns, Halper, & Mogil, 1985).
Conversational initiation. Conversational responsiveness and participation. Turn
taking: co-operation in ‘floor sharing’, with reference to, e.g. interruption, reluctance to
relinquish the floor. Verbosity. perceived appropriateness of length of turn with reference

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to, e.g. inclusion of unnecessary or peripheral detail and repetition. Topic maintenance:
relevance of contribution to topic in hand with reference to, e.g. unsignalled topic change
and introduction of irrelevant material. Referencing: coherence in referring to people and
events, enabling the listener to keep track of who and what is under discussion. Intonation:
variation in intonational contour, without reference to voice quality or habitual pitch.
Facial expression: perceived appropriateness of facial expression. Eye contact: perceived
appropriateness of pattern of maintenance and interruption. Ratings were summed on the
five verbal parameters to provide a conversational interaction (CON) score (maximum 25)
and on the three non-verbal parameters to provide a non-verbal (NV) score (maximum 15).
Additionally for the RBDNR group, naming ability was assessed using the Graded
Naming Test (GNT) (McKenna & Warrington, 1983).
For stroke participants, communication assessment was carried out within 3 days of the
3 months post-stroke date. Assessors had access to the handedness and neurological status
information of participants. Spoken responses were audiorecorded for transcription and
analysis. Eye contact and facial expression parameters of conversation were rated at the
time of data collection. For the scoring of picture description and all other conversation
parameters, following initial practice and discussion, intra-judge and inter-judge
reliability was assessed on 20% of the data from the RBD and NBD databases from
which the participants for this study were drawn (respectively, 70 and 189 subjects).
Agreements for all measures used in this study were at least 90%. Repeat testing of 20% of
the group of 189 NBD subjects took place after an interval of 2 months. For all measures
used in this study correlations between T1 and T2 were significant ð p , 0:01Þ and
performance differences were non-significant ð p . 0:05Þ: Full details are given in
Mackenzie (2000) and Mackenzie et al. (1999).

3. Results
Communication assessment scores of the three participant groups are contained in
Table 2. Given the nature and size of the group compositions and the ordinal level of
measurement, non-parametric analysis procedures were used (Kruskal Wallis one way
analyses of variance followed by Mann Whitney U tests for relevant pairwise
comparisons). Two tailed tests were used. In view of the small size of the RBDNR
group the significance level was set at p ¼ 0:05 and exact rather than asymptotic
significance reported for Mann Whitney tests.
Variance amongst the groups was significant in four of the nine measures: two relating
to comprehension (DCT, CIMT) and two relating to spoken discourse (CTEFF, NV). In
two other measures (MPT, CTIU) non-significant trends were apparent. For these six
measures pairwise comparisons were carried out (Table 3). The R and NR RBD groups
showed no performance differences. Both RBD groups had lower scores than the
neurologically normal group in a number of tasks. The task which most distinguished the
performance of the RBD groups, both R and NR, from the NBD group was the non-verbal
conversational score. In the Comprehension of Inferred Meaning Test also, both RBD
groups scored less well than the NBD group. For two further comprehension tests (DCT
and MPT) significant between group differences were present for RBDR and NBD,

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Table 2
Communication assessment scores: means and standard deviations
Measure

RBDNR ðN ¼ 5Þ

RBDR N ¼ 9Þ

NBD ðN ¼ 20Þ

p

ASJ (30)
DCT (40)
MPT (10)
CIMT (12)
CTIU
CTEFF
CTEXT
NV (15)
CON (25)

28.20 (2.05)
32.80 (3.96)
6.40 (2.51)
6.60 (2.19)
4.60 (1.14)
6.06 (1.38)
32.20 (8.89)
12.20 (1.10)
22.20 (1.79)

27.50 (2.00)
32.22 (1.64)
5.44 (3.54)
7.33 (2.06)
4.78 (2.05)
6.21 (2.91)
30.28 (17.54)
11.22 (2.54)
23.00 (1.41)

28.15 (1.76)
34.55 (3.90)
7.90 (3.01)
9.10 (1.92)
6.90 (3.04)
4.68 (1.74)
51.34 (36.14)
14.75 (0.44)
23.55 (2.06)

0.645
0.043*
0.064
0.029*
0.088
0.045*
0.148
0.000*
0.144

*p , 0:05; ASJ: Auditory synonym Judgements, DCT: Discourse Comprehension Test, MPT: Metaphor
Picture Test, CIMT: Comprehension of Inferred Meaning Test, CTIU: Cookie theft interpretive units, CTEFF:
cookie theft efficiency-higher scores indicate decreased efficiency, CTEXT: cookie theft extraneous information,
NV: conversation non-verbal, CON; conversation interaction; RBDNR: right brain damage, non-right handed,
RBDR: right brain damage, right handed, NBD: non-brain damage.

whereas the RBDNR group was not different from NBD. In the picture description
efficiency measure the RBDNR group were significantly impaired in relation to normal
and for the RBDR group there was a distinct trend in the same direction. Also for RBDNR
there was a non-significant trend towards picture description interpretive unit scores being
lower than for NBD.
All RBDNR participants were low scorers in some measures. Table 4 gives individual
measure scores for each RBDNR participant and indicates those measures on which
performance was lower than one SD below the mean for the relevant published NBD age
and education controlled data (Mackenzie, 2000a,b). For GNT, low scores are similarly
identified with reference to McKenna and Warrington (1983) mean (22.54, SD: 4.3).
NV was the only measure where by this standard the RBDNR group were consistently
low performers. For CIMT four of the five participants were likewise impaired. Four
participants had low scores on GNT. RBDNR2 and RBDNR3 showed the greatest number
of low scores (six of the 10 measures). RBDNR4 was impaired in the lowest number of
measures (two) and was the only one of the group to score within 1SD of the GNT mean.
RBDNR1 was impaired in three and RBDNR5 was impaired in four measures.
Table 3
Communication assessment performance: between group comparisons

NBD vs. RBDR
NBD vs. RBDNR
RBDNR vs. RBDR

DCT (40)

MPT (10)

CIMT (12)

CTIU

CTEFF

NV (15)

* p ¼ 0:010
p ¼ 0:303
p ¼ 1:00

* p ¼ 0:049
p ¼ 0:112
p ¼ 0:797

* p ¼ 0:049
* p ¼ 0:035
p ¼ 0:438

p ¼ 0:127
p ¼ 0:060
p ¼ 0:699

p ¼ 0:069
* p ¼ 0:035
p ¼ 0:797

* p ¼ 0:000
* p ¼ 0:000
p ¼ 0:606

* p , 0:05:; DCT: Discourse Comprehension Test, MPT: Metaphor Picture Test, CIMT: Comprehension of
Inferred Meaning Test, CTIU: Cookie theft interpretive units, CTEFF: cookie theft efficiency, NV: conversation
non-verbal.

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C. Mackenzie, M. Brady / Journal of Neurolinguistics 17 (2004) 301–313

Table 4
Individual RBDNR participant scores

GNT (30)
ASJ (30)
DCT (40)
MPT (10)
CIMT (12)
CTIU
CTEFF
CTEXT
NV (15)
CON (25)

RBDNR1

RBDNR2

RBDNR3

RBDNR4

RBDNR5

13a
29
33
8
7b
4
5.33
24
12b
22

16a
26b
28b
2b
4b
6
4.67
28
11b
22

15a
26b
32
7
6b
3b
7.44b
44.67
14b
22

21
30
32
7
6b
5
5.20
26
12b
25

18a
30
39
8
10
5
7.67b
38.33
12b
20b

GNT: Graded naming Test, ASJ: Auditory synonym Judgements, DCT: Discourse Comprehension Test,
MPT: Metaphor Picture Test, CIMT: Comprehension of Inferred Meaning Test, CTIU: Cookie theft interpretive
units, CTEFF: cookie theft efficiency, CTEXT: cookie theft extraneous information, NV: conversation nonverbal, CON; conversation interaction.
a
Scores below 1 SD of NBD mean performance (McKenna & Warrington, 1983).
b
Scores below 1 SD of NBD mean performance (Mackenzie, 2000a,b).

4. Discussion
Performance data on measures sensitive to the subtle communication effects associated
with RBD have not previously been reported for NRs sustaining right hemisphere stroke.
A group, albeit small, of NRs of similar educational background and with communication
assessment carried out at the same point in time after stroke (3 months), permitted the
examination of some relevant data. Given the small number of RBDNR participants, the
reaching of firm conclusions is not warranted but some preliminary observations may be
forwarded along with some suggestions for future research.
On all communication measures there was striking similarity between the scores of the
RBD R and NR groups. This is contrary to the findings of Gloning et al. (1969) whose NR
group was significantly more impaired. It should be noted that this older study involved
only global judgements using traditional language measures and participants of
unspecified lesion type. There may also have been some differences in handedness
patterns, in that all of Gloning et al’s NR group had been required to write with the right
hand at an early school stage though some had reverted later to left hand writing. Time of
assessment may also contribute to the conflicting results. The Gloning et al data were
collected in the first week following stroke and it is possible that recovery after this stage
contributes to erosion of group differences. The lack of differentiation of R and NR groups
is in accord with recent language data for left brain damage (Basso et al., 1990; Kertesz,
1993; Laska et al., 2001; Naeser & Borod, 1986; Pedersen et al., 1995).
Unlike previous research involving NRs, participants were not recruited on the basis of
a demonstrated communication difficulty. The research was not concerned with diagnosis
of aphasia, but to evaluate whether Rs and NRs performed similarly in tests associated
with RBD impairment. The presence of communication deficit is clear in that while the
scores of both stroke groups were remarkably similar, they were impaired in comparison to

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309

the non-brain damaged group on several measures, relating to spoken discourse and the
comprehension of connected speech. Despite the small group sizes, some clear
performance differences between the stroke and neurologically normal groups were
demonstrated at 3 months after stroke, a stage where stability of communication
performance is expected (Laska et al., 2001; Pedersen et al., 1995; Holland, Greenhouse,
Fromm, & Swindell, 1989).
Low scores on communication tasks may represent a reduction in cognitive processing
ability as distinct from a communication specific impairment (Cherney & Halper, 1996).
Taxing tests of inferential comprehension, where understanding of the presented material
requires the listener to deal with information, which is not given explicitly have frequently
been found to be sensitive to RBD (Harden, Cannito, & Dagenais, 1995). Such tests exact
high demands of cognitive processes, such as sustained attention, memory, and reasoning.
Both R and NR groups performed less well than the NBD group on CIMT. Recent brain
imaging data on lateralisation of language (Springer et al., 1999; Szaflarski et al., 2002)
and visual perception and memory (Grady, 1996) have revealed a more symmetric pattern
of activation in older than in younger people. These findings have led to the suggestion that
cognitive functions may become less lateralised with advancing age, reflecting
compensation for age-related capacity loss (Szaflarski et al., 2002). While similarity of
performance in Rs and NRs does not signify that the groups have comparable processing
impairments or patterns of cerebral language organization, reduced lateralisation may be a
relevant contributor to the observed similarities of language performance in R and NR
patients. Although RDDR and RDDNR groups were not differentiated on any of the
measures of comprehension, there were indications of a more extensive comprehension
loss in the RBDR group. In addition to the low scores on CIMT, which both RBD groups
showed, in both DCT and MPT, the RBDR group scored significantly below the NBD
group. Previous investigators using these assessments have similarly reported impairment
for RBDR subjects (Bryan, 1989; Tompkins, Baumgaertner, Lehman, & Fossett, 1997).
More diffuse organization of sentence and paragraph comprehension skills in the NR
group may have provided some protection against the effects of RBD, whereas the high
cognitive demands of CIMT resulted in impaired performance in both R and NR RBD
groups.
Four of the five RBDNR participants experienced difficulty with GNT, the word finding
test administered to this group only, when only RBDNR1 was frankly aphasic in the view
of the assessing speech and language therapist. The presence of aphasia did not affect
participation in the assessments. Low confrontation naming scores are not specifically
associated with RBD, although problems with divergent word finding tasks have been
noted (Hough, Pabst, & DeMarco, 1994; Varley, 1995). The low education level of the
group and the inclusion of three elderly participants may have influenced group
performance on GNT. However, reduction in word retrieval proficiency in the RBDNR
group is suggested by the picture description efficiency measure which showed that
relative to the total words used in description the amount of relevant content was lower
than for neurologically normal subjects. A similar non-significant trend was present for the
RBDR group. This may be a further indication of cognitive compromise in relation to
general processing efficiency and the requirement for sustained attention in the picture

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description task. Also this task and GNT use visual material and performance may be
affected by impairments in visual perception which may be associated with RBD.
In Rs the right hemisphere is regarded as having a specialized role in a variety of higher
functions and impairments related to for example attention, praxis, affect, and visuospatial
skills are thought to be typically associated with non-dominant hemisphere lesions (Myers,
1999; Coppens & Hungerford, 2001). It is unknown whether the same applies to NRs with
left language lateralisation, whether the left hemisphere fulfils this function if language is
lateralised in the right hemisphere or whether both hemispheres contribute should
language be bilaterally represented. Coppens and Hungerford (2001) hypothesise an
independence in the lateralisation of language and visuospatial skills. Alexander and
Annet (1996) report a left handed patient with a left lesion in whom language, praxis,
affect, and visuospatial skills appeared to all be lateralised in the right hemisphere. Future
research in NRs with RBD should examine communication difficulties in the context of
other lateralised functions to inform the relationship between language and other higher
functions.
The desirability of viewing communication behaviours within a broader context is also
clear when the non-verbal scores of the RBD participants are considered. The NV score,
which were based on eye contact, facial expression and intonation during conversation,
was the communication measure, which most distinguished the stroke participants, both R
and NR, from the NBD group. However, it should be noted that the ratings for eye contact
and facial expression were made at the time of assessment so were not subject to the
rigorous inter and intra judge reliability monitoring which was applied to the other spoken
language measures. Future research might make use of video rather than audio recording
or have a second judge in attendance during a representative proportion of data collection.
The reason for the presence of the suggested limitations in these non-verbal behaviours
cannot be determined from the current study. Although these are pragmatic dimensions
which are associated with RBD, motor speech impairment, depression and affective
disorder may all have some bearing on the low scores of R and NR RBD stroke patients.
Only RBDNR1 was perceived to exhibit some aphasia, which suggests that the right
hemisphere played a significant role in language processing in this participant. Although
RBDNR1 was the lowest scorer on GNT and despite the aphasia, overall on the
communication battery he was certainly not the weakest of the group and in the majority of
measures scored around the NBD mean for his age and education grouping This may be
because for this participant the left hemisphere subserved the communication role which
in right handers is associated with the right hemisphere. The other four NR participants
were not regarded as aphasic and it is likely that for them the right hemisphere was
less involved in language processing. Further speculation about patterns of language
lateralisation in the RBDNR group in this investigation would be inappropriate. Until
recently, knowledge about the lateralisation of language processing and the heterogeneity
of the NR population was based on brain damaged groups and the results of experimental
procedures, such as Wada’s intracarotid sodium amytal test and unilateral electroconvulsive shock. The information becoming available from investigations which employ
modern neuroimaging techniques enhances and challenges our knowledge base,
confirming right hemisphere language activity in Rs (Knecht et al., 2000; Springer et al.,
1999) and revealing that for NRs some participation of the right hemisphere is frequent,

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311

but complete right hemisphere lateralisation is very uncommon. (Pujol, Deus, Losilla, &
Capdevila, 1999) The majority of relevant imaging studies have used single word
recognition and generation tasks. Future research using imaging techniques will hopefully
include a variety of language measures, sampling comprehension and production and also
higher level communication tasks which are sensitive to RBD.
In research where handedness may be relevant there is a need for clearly defined
groups. Various methods for assessing handedness have been used, including selfreport, preference inventories, and task performance. The categorization of people into
right and non-right-handed groups masks the continuum of laterality patterns which
are present in the population and which have an association with language dominance.
Handedness should be defined using multiple measures that assess different aspects of
preference and performance (Corey, Hurley, & Founda, 2001). Familial handedness
may be relevant to language organization (Knecht et al., 2000). None of the NRs in
the current study recalled left handedness in parents. It may be relevant to question
regarding other relatives also. However, it must be recognized that the exploration of
familial handedndess patterns is problematical especially in cultures such as in the UK
where in previous generations many people with left handed tendencies were
pressurised to use the right hand and even punished for not doing so at school.
Recent research on language performance of right and NRs have not revealed
differences in neurologically intact adults (Szaflarski et al., 2002) nor in children
(Natsopoulos, Koutselini, Kiosseoglou, & Koundouris, 2002), thus justifying the
absence of a non-brain damaged non-right handed group in this study. Nevertheless
until knowledge in this area is more complete, future larger scale research involving
NRs should consider the inclusion of a NR control group reflecting the distribution in
the adult population. It is hoped that this initial report will stimulate interest in
communication skills associated with non-dominant hemisphere language processing
in the non-right-handed population. The research contributes to the growing body of
evidence as to the similarity of presentation of Rs and NRs on communication
assessment. Nevertheless, the literature confirms wide variation in performance in
language tasks in neurologically normal and in brain damaged people and small
groups may not be truly representative of their populations. Only further research will
demonstrate whether performance differences which were not apparent in the right
brain damaged right handers and NRs in this small investigation are evident when
larger groups are studied.

Acknowledgements
The research was supported by funding from the Stroke Association and the University
of Strathclyde. The authors are grateful to the Department of Radiology, Western
Infirmary, Glasgow and to Professor KR Lees for clinical stroke classification and scan
review and to Mrs T Begg, speech and language therapist, for her collaboration in the right
hemisphere stroke communication research programme.

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