Keywords
anomic - stroke survivors - aphasia - conceptual task
Introduction
Aphasia is defined as the loss or deficiency in expressive and/or receptive language,
and is generally caused by a left hemisphere lesion, such as a stroke.[1] Aphasia is a common cause of neuropsycholinguistic (or cognitive-linguistic) impairment,
and is the most disabling conditions, affecting communication and social skills in
general. Generally, persons with aphasia (PWAs) have deficits in combining words together,
framing meaningful sentences, having trouble reading, or having a hard time in understanding
the spoken language. These deficits can be caused due to impairment at the conceptual
level or at the lexical level.
A concept may be considered as a basic unit of thought. Conceptual knowledge can be
described as ideas, relationships, connections, or having an understanding of something.[2] Conceptual knowledge refers to understanding and interpreting concepts and concepts'
relationships.[3] Conceptual knowledge is needed as a guide for our actions. Our knowledge of how
to use concrete objects as a guide for our actions is our conceptual knowledge.[4] Lexical knowledge is knowledge that can be expressed through words.[5] The lexical knowledge consists of all the information that we know about words and
their relationships.
The term conceptual impairment refers to a disturbance in the thinking process or
in the ability to formulate abstract ideas from generalized concepts.[6] Deficit in lexical processing refers to any difficulty producing a single word,
or difficulty in reading a word and comprehending a single word, phrase, and sentence
level. Lexical errors (e.g., reading table for chair, chain for chair, etc.) can also
be considered as lexical deficits.[5]
Lexical deficits are predominantly occurred for verbs, verb retrieval deficits are
pervasive that can have profound impact on communication of PWAs.[7] In general, impairment in verb retrieval might occur owing to lexical or conceptual-processing
deficits. The verb retrieval process, therefore, plays an important role in sentence
formulation.
The retrieval of verbal information in healthy adults and in PWAs depends on both
linguistic and conceptual processing. In PWAs, these deficits can co-occur and be
correlated, but for patients with various acquired brain injuries, these deficits
can be dissociated. Verb retrieval impairments can be caused by impaired conceptual
action processing than lexical retrieval impairments in aphasia.[7] Despite the positive findings, the study findings seem to be in preliminary, owing
to heterogeneous population and small sample size. Also, the positive findings are
evinced merely in English language, and this necessitates the researchers to explore
the paradigm in other languages, owing to the difference in the sentence structures
of the languages. So thereby to bridge this gap, the current study focuses on understanding
how PWAs word retrieval impairment occurs in conceptual and linguistic processes in
Kannada language (a regional language spoken in the state of Karnataka, India).
Understanding the dissociations between verb and lexical impairments is crucial, owing
to understanding what kind of cues facilitate better retrieval or what kind of strategies
can be ideal during assessment of conceptual or lexical level impairment in PWAs.
Thus, the study aimed to compare the conceptual and linguistic impairments associated
with fluent and nonfluent PWAs. To accomplish the aforementioned aim, following objectives
were assessed. The performance of conceptual and lexical retrieval abilities in fluent
and nonfluent aphasic in isolation was compared. Further, the performance of conceptual
retrieval abilities in fluent versus nonfluent aphasia was compared. The performance
of lexical retrieval abilities in fluent versus nonfluent aphasia was compared.
Materials and Methods
A total of 15 PWAs aged between 30 and 80 years were recruited, out of these participants
“8” PWAs were fluent and “7” were nonfluent aphasia (see [Table 1]). These participants were selected based on convenient sampling method, and cross-sectional
research design was used to carry out the experimental paradigm of the study. Participants
selected for the study given their consent to be the part of the study, and the study
was approved by the Father Muller Institutional Ethics Committee (FMIEC/CCM/268/2022).
Table 1
Demographic characteristics of participants
|
Sl. no.
|
Age/sex
|
Education
|
Occupation
|
TPO
|
Etiology
|
Diagnosis
|
|
1
|
66 y/M
|
10th grade
|
Driver
|
6 mo
|
L-MCA
CVA
|
Anomic aphasia
|
|
2
|
59 y/M
|
12th grade
|
Business
|
7 mo
|
L-MCA
CVA
|
Broca's aphasia
|
|
3
|
68 y/M
|
10th grade
|
Business
|
8 mo
|
L-MCA
CVA
|
Broca's aphasia
|
|
4
|
79 y/M
|
10th grade
|
Farmer
|
3 mo
|
L-MCA
CVA
|
Anomic aphasia
|
|
5
|
57 y/M
|
Graduate
|
Business
|
11 mo
|
L-MCA
CVA
|
Anomic aphasia
|
|
6
|
38 y/M
|
Graduate
|
Accountant
|
3 mo
|
L-Frontoparietal
CVA
|
Wernicke's aphasia
|
|
7
|
52 y/F
|
10th grade
|
Housewife
|
2 mo
|
L-MCA
CVA
|
Broca's aphasia
|
|
8
|
72 y/M
|
Graduate
|
Ex-military
|
6 mo
|
L-MCA
CVA
|
Broca's aphasia
|
|
9
|
48 y/M
|
Graduate
|
Priest
|
6 mo
|
L-MCA
CVA
|
Anomic aphasia
|
|
10
|
69 y/M
|
Graduate
|
Military
|
2 mo
|
L-MCA
CVA
|
Broca's aphasia
|
|
11
|
47 y/M
|
Graduate
|
Salesman
|
9 mo
|
L-MCA
CVA
|
Broca's aphasia
|
|
12
|
50 y/M
|
10th grade
|
Farmer
|
6 mo
|
L-Fronto parietal
CVA
|
Wernicke aphasia
|
|
13
|
60 y/M
|
10th grade
|
Waiter
|
8 mo
|
L-Fronto parietal
CVA
|
Wernicke aphasia
|
|
14
|
56 y/M
|
12th grade
|
Salesman
|
5 mo
|
L-MCA
CVA
|
Anomic aphasia
|
|
15
|
50 y/M
|
10th grade
|
Farmer
|
9 mo
|
L-MCA
CVA
|
Broca's aphasia
|
Abbreviations: CVA, cerebrovascular accident; L-MCA, left middle cerebral artery;
TPO, time postonset.
The inclusion criteria followed in the study were the participant should be right-handed
prior to stroke, should be native Kannada speakers (fair to good proficiency in reading
and writing), and should be free from vision impairment and hearing loss. Similarly,
the current study inculcated following exclusion criteria such as aphasia with concomitant
disorder, PWAs who had <5 score in auditory verbal comprehension, education levels
below the 10th grade, aphasia due to head injury, history of behavioral issues, drug
or alcohol abuse, and PWAs scoring >100 on action naming test (ANT), if PWAs are showing
any of the aforementioned conditions, then those participants were excluded from the
study.
Shyamala et al[8] used the Kannada version of Western Aphasia Battery to determine the presence and
type of aphasia. Girish[9] used ANT to assess the verb retrieval abilities. To assess verb and action processing,
all PWAs underwent a series of behavioral language and conceptual knowledge tests.
The stimulus was prepared using a standardized action knowledge battery.[7] The battery intended to assess lexical and conceptual abilities of verbs in PWAs.
The action knowledge battery comprised (1) two picture-based conceptual tasks (picture
attribute and picture comparison judgments) and (2) two verb-based language tasks
(word attribute and word comparison judgments).
The study utilized task such as naming, picture comparison, picture attribute, word
comparison, and word attribute. All these tasks were presented via laptop. Participants
were given specific instructions for each task with the practice trails. In addition
to an action naming task, participants also performed two conceptual, picture-based
tasks, that is, picture characteristics and picture comparison judgment task and two
linguistic, verb-based tasks such as word attributes and word comparison judgment
task, and one verb retrieval task. Time given to respond to the stimulus was 60 to
80 seconds and interstimulus interval of 30 seconds was fixed.
To delineate the naming task (N = 20 items), the PWAs enrolled in the study was shown an action and solicited for
the response pertaining to the item presented. If the response was evinced in the
absence of cues, a score of “two” was awarded. If the participants were unable to
respond, they were provided with semantic cues initially, followed by contextual and
phonemic cues. The score of “one” was provided in case of semantic cues, phonemic
cues, or contextual cue. Score of “zero” was given for incorrect or incomplete response
(see the presence of noun or verb).
In picture comparison task (N = 20 items), the PWAs were provided with three choices here PWAs were instructed
to select to the image which has different meaning among them. In picture attribute
task (N =20 items), the PWAs were provided with two colored images of actions for each item,
along with an attribute judgment. In word comparison task (N = 20 items), the PWAs were presented with three printed verbs for each item. The
verbs were read aloud by the experimenter, here PWAs were instructed to choose the
verb that differed from the array of choices. In word attribute task (N = 20 items), the PWAs were presented with two printed verbs and an attribute judgment question.
The researcher read the verbs and the question out loud. The participant was asked
to choose the verb that best addressed the given question (e.g., “Which action would
make to go urgently to a place?”).
In all the aforementioned tasks, PWAs were score based on binary system, that is,
score of “one” was awarded for the correct response, score of “zero” was provided
in case of no response, incorrect, or incomplete response (see the presence of noun
or verb).
Version 17.0 of the Statistical Package for Social Sciences (SPSS) was used to analyze
the data. The Shapiro–Wilk's test was used to determine the normality for the computed
data, and the results showed data were normally distributed (p > 0.05). Owing to which parametric tests were used to analyze the data. Using the
paired t-test within groups comparison was done. Using an independent t-test, groups were compared against one another.
Results
Descriptive analysis evinced no difference in the performance of fluent aphasia in
both conceptual and lexical tasks. Further similar trend of results was noted even
in nonfluent aphasia for both conceptual and lexical tasks (see [Fig. 1]).
Fig. 1 Mean scores of fluent and nonfluent aphasia across conceptual and lexical tasks.
Further paired t-test was used to see the statistical difference and the results evinced there is
no statistically significant differences between the performance of conceptual and
lexical retrieval skills in both fluent and nonfluent aphasia (fluent aphasia: t(7) = 0.29, p = 0.77; nonfluent aphasia: t(6) = 0.08, p = 0.93) (see [Table 2]).
Table 2
Score of participants on conceptual and lexical tasks
|
Conceptual task
|
Lexical task
|
|
Sl. no.
|
Type of aphasia
|
Action naming
|
Picture comparison
|
Picture attribute
|
Word comparison
|
Word attribute
|
|
1
|
F
|
40
|
19
|
19
|
15
|
20
|
|
2
|
N
|
32
|
16
|
19
|
10
|
17
|
|
3
|
N
|
34
|
10
|
20
|
10
|
19
|
|
4
|
F
|
30
|
8
|
16
|
7
|
9
|
|
5
|
F
|
36
|
20
|
18
|
19
|
18
|
|
6
|
F
|
30
|
10
|
12
|
12
|
14
|
|
7
|
N
|
40
|
17
|
19
|
16
|
18
|
|
8
|
N
|
30
|
15
|
14
|
16
|
18
|
|
9
|
F
|
38
|
17
|
19
|
16
|
18
|
|
10
|
N
|
38
|
9
|
20
|
14
|
19
|
|
11
|
N
|
28
|
14
|
20
|
16
|
20
|
|
12
|
F
|
30
|
11
|
11
|
14
|
12
|
|
13
|
F
|
40
|
11
|
19
|
9
|
20
|
|
14
|
F
|
40
|
13
|
13
|
17
|
20
|
|
15
|
N
|
36
|
19
|
20
|
16
|
20
|
Abbreviations: F, fluent aphasia; N, nonfluent aphasia.
The descriptive analysis revealed that the mean scores for nonfluent aphasia are slightly
higher than for fluent aphasia (see [Fig. 1]). Further, independent t-test was used to see the statistically significant difference and results showed
that there is no statistically significant differences between the performance of
conceptual retrieval skills in fluent and nonfluent aphasic speakers (fluent aphasia:
t(7) = 0.29, p = 0.77).
The descriptive analysis revealed nonfluent aphasia has marginal increased mean scores
than for fluent aphasia. Further, independent t-test was used to see the statistically significant differences and the results discerned
there were no significant differences between the lexical retrieval abilities of fluent
and nonfluent aphasia (t(6) = 0.08, p = 0.93).
Discussion
The study focused on understanding how the verb retrieval affects, if there is specific
impairment at conceptual or lexical level. The study emphasized the significance of
lexical–conceptual system interactions in defining verb retrieval performance in PWAs.
In stroke survivors, lexical and conceptual processing deficits are commonly noticed
and there are evidence manifesting that lexical features and conceptual representations
may aid to pinpoint verb retrieval deficits.[10]
[11] The interactions or potential links between lexical and conceptual deficits and
their interactions with language functions such as naming has not yet been demonstrated.
Additionally, the evidence is inconclusive as to whether or when lexical and conceptual
action-processing abnormalities may separate after a stroke.[12] Thus, it is unclear how verb retrieval issues in aphasia are affected by abnormalities
in lexical and conceptual action processing.
Processing of lexical items, conceptual knowledge, and action naming were all three
sets of tasks that PWAs consistently underperformed. These results confirm earlier
research showing that action naming (verb retrieval) is frequently reduced in aphasia,
with verb retrieval deficiencies present in ∼70% of aphasics.[13] They are also in line with other research showing that aphasia in particular and
stroke specifically may both affect processing at lexical and conceptual action.[12]
[14] It is noteworthy that conceptual and lexical abilities both predicted success in
naming actions, and the presence of aphasia increased the influence of both traits
on naming abilities.
The current study did not evince any statistically significant difference between
the performance of conceptual and lexical retrieval skills in fluent and nonfluent
aphasic speakers in isolation. The findings of the study posit that fluent and nonfluent
aphasia groups retrieve verb both at lexeme and lemma levels.[12]
[14] These results of the study could also be attributed to the complexity of the tasks,
in which in both the conditions investigator employed merely verification task. Hence,
the response would be better performed.
Additionally, the current study also showed no changes in fluent and nonfluent aphasia
in conceptual retrieval tasks. Furthermore, there were no observable differences in
lexical retrieval abilities between fluent and nonfluent aphasic speakers. Words were
utilized in lexical, and pictures were utilized in conceptual tasks deemed to lack
complexities. Thus, the PWAs responded with ease to the given stimulus.
Furthermore, the ANT test showed that persons with fluent aphasia manifest impairment
at both conceptual and lexical abilities. These results are in consensus with Saygin
et al[14] who evinced that the participants with mild and fluent aphasia exhibited a correlation
between conceptual and linguistic tasks. On the other hand, participants with severe
and nonfluent aphasia showed profound effect at linguistic performance.
The current study findings show, regardless of conceptual–linguistic correlations,
persons with nonfluent aphasia show profound impairment at both conceptual and lexical
action processing. These findings are novel, and they show that verb retrieval problems
in aphasia are caused by problems with both lexical and conceptual processing.
Limitations
The study exclusively employed ANT test to identify the retrieval impairment in PWAs.
However, the ANT test only assesses performance concerning semantic and phonemic cues,
as well as error responses. Along with ANT, the other level of assessment at sentence
and conversation level is recommended for comprehensive evaluation. Employing the
verification method captured responses for both conceptual and linguistic tasks, yet
integrating verbal retrieval methods could offer deeper insights into a wider range
of responses.
Conclusion
The current study findings shed a light on equally affected conceptual and lexical
impairments in PWAs, irrespective of their types. The study results assist in documenting
difficulties with retrieving information either at the conceptual or lexical level.
This enables speech language pathologists to determine the most effective cues for
therapy depending on the specific nature of the impairment. However, this result should
be interpreted with caution owing to small sample size and lack of complexity associated
with the experimental paradigm.
