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ABSTRACT
Naming is a mental process requiring reperesentations
of semantic, phonologic and morphosyntactic information
of our mental lexicon. Many neurological conditions
including neurodegenerative diseases such as Dementia
of Alzheimer's type (DAT) and acute brain lesions
leading to aphasia, bring about confrontational
naming deficits which are considerably different
by nature, and investigation of them may open
a gate to better understanding of brain cognitive
mechanisms in terms of language processing. The
purpose of the present study was to compare visual
confrontation naming performance of patients with
DAT and aphasia and to evaluate the effects of
semantic-phonologic priming on this performance
in an Iranian aged sample.
Method. 20 patients with DAT compared
with 17 patients with aphasia using a reference
group of healthy elderly people. All the participants
were examined using Farsi Aphasia Naming Test
developed by Nilipour (2004). Data regarding the
correct responses without any cues, with semantic
priming and phonological priming were analyzed
by T test using the software SPSS.
Results. The results showed that there
is a significant difference in correct responses
without any cues between 2 groups( p=0.000) with
aphasic patients being less able to name the pictures
correctly. Significant differences also seen by
using semantic (p=0.000) and phonological priming(
p=0.000). DAT group functioning improved by semantic
priming, whereas the aphasic group did better
with phonological priming.
Conclusion. It is concluded that naming
difficulties in DAT patients are mostly arising
from semantic memory deficits, whereas in aphasic
patients the problem has a lexical-phonological
origin. This finding may also have some implications
in the early diagnosis of DAT patients.
Key Words: Picture naming test, Anomia,
fluent aphasia, Alzheimer'disease, Aged people.
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INTRODUCTION
Confrontation naming performance
is one of the important language functioning indices
which is often assessed by picture naming tests. These
neuropsychological tests typically include pictures
of familiar objects such as tools, fruits, animals,
etc. which should be named by the subject. Anomia is
one of the very early symptoms observed in patients
with dementia of Alzheimer type (DAT) and, also, a universal
frequent symptom in aphasic patients. However the nature
of the two problems is considerably different. As Randolph
et al. mentioned ," ... little work has been done...
to determine how various demographic, linguistic, and
disease status variables influence patterns of performance
on these tests" (Randolph et al., 1999). Anomia
in patients with DAT is supposed to have a semantic
nature (Small et al.,2006; Garrad et al., 2005) resulting
from deterioration of semantic memory. But some studies
have stressed the role of post semantic deficits such
as phonological lexicon activation in DAT patients (Delazer,et
al,2003). A tendency is increasing among researchers
to consider semantic anomia in DAT patients as a category
- specific deficit (Albanese, 2007; Whatmough et al.,
2003; Dion Fung et al., 2001) but this category specificity
is by no means so prominent in aphasic patients, a fact
which may be confirmed by the well-known verb-noun double
dissociation in aphasic patients (Crepaldi et al.,2006;
Luzzatti et al., 2002). Also some authors oppose the
semantic nature of anomia in DAT patients and attribute
it to visual object recognition deficits (Done and Hajilou,2005;
Simons et al., 2002; Hajilou and Done, 2007). The status
for local acute lesions is much different. Aphasia arising
from selective local impairments has been the subject
of more detailed linguistically based tasks and also
development of useful tools for testing psycholinguistic
models (Wilshire et al., 2007). Margolin et al showed
that impaired word finding reflected impaired processing
of semantic information in the patients with DAT, whereas
in the anomic patients impaired processing related to
the lexical-phonological information (Margolin et al.,
1990). Some studies have shown that phonological priming
is the most effective cue in confrontational tasks for
aphasic patients regardless of type and severity of
their impairments (Howard &Lisle,1984; Kay &Ellis,1987).
But Stimely et al. claimed that naming accuracy of aphasic
patients was facilitated by both phonemic and semantic
cues (Stimely & Noll,1991). Also, Butterworth et
al. discussed that the incidence of semantic comprehension
errors was not related to aphasic diagnostic group but
to the overall severity of aphasia (Butterworth et al.,
1989). The present study was designed to compare visual
confrontation naming performance in patients with DAT
and aphasic patients and to assess the effects of semantic-phonologic
priming on the Performance.
MATERIALS
AND METHODS
Participants - Two groups of
patients participated in this study. The first group
included 20 patients (8 female and 12 male) with dementia
of Alzheimer type (DAT) who were the clients of Iranian
Alzheimer Association- Tehran division and had been
successively presented to the attending psychiatrist
of the association and met the criteria of DSM-IV-TR
for the diagnosis of Alzheimer's disease and also the
MMSE score <27 at the interval of 2005-2006. The
second group consisted of aphasic patients who were
referred by speech therapy section of rehabilitation
centers of Tehran and Mashhad at the interval of 2005-2006.
They all suffered from an ischemic CVA damaging left
perisylvian area which primarily included left temporoparietal
region leaving them with a somewhat fluent aphasia,
relatively spared oral expression skills and anomia.
All the patients were literate ( able to read and write)
and in both bilinguals and monolinguals, Farsi was their
primary language at the time of the disease.
A group of healthy elderly individuals
were participated in the study as control group. They
were able to read and write, in both bilinguals and
monolinguals. Farsi was their primary language at the
time of the study. None of them had a history of neurological,
sensory or motor problems or any complaints of memory
loss in the last few months.
After clearly explaining the
aim and the process of the present study to the referred
individuals, those who signed the consent letter entered
the study. The letter was signed by the primary care-giver
in the case that the ptient was not able to give the
informed consent due to her/his cognitive impairment.
This study, also, gained the approval of the Research
Ethical Committee of the University of Social Welfare
and Rehabilitation.
Tools - A questionnare designed
to gather demographic and medical data was applied to
all of the subjects. MMSE scores of patients with DAT
and the normal group were obtained by using MMSE section
of the Pocket Guide of Elderly Health Evaluation provided
by Iranian Research Center on Aging ( Iranian Research
center on Aging, 2003). The aphasic patients were examined
by Farsi Aphasia Test ( Nilipour, 1994) to provide the
differential diagnoses and the whole picture of the
patient's language performance.The major tool of the
study was Farsi Aphasia Naming Test ( Nilipour , 2004)
which is structurally much similar to Armstrong Naming
Test (Armstrong, 1996). It is a picture naming test
consisted of 50 pictures of familiar objects including
ordinary tools, animals and fruits. Each picture is
shown to the subject and (s)he is asked to name it orally.
There are 4 columns in the answer sheet consisting of
1)responded without any priming
2) responded with semantic priming
3) responded with phonological priming and
4) the type of error.
Every noun is characterized
by an underline below the first syllable used for phonological
priming and a short sentence describing the name used
for semantic priming.At first the participant is subjected
to the picture without any help. If (s)he could not
respond in 10 seconds , the semanic priming is introduced
and again if (s)he could not respond, the phonological
priming is given. Finally the rates and percents of
the responses in each column are converted into a profile.
RESULTS
The data analysis showed that
the first group, the patients with Alzheimer's disease,
consisted of 20 patients including 8 females and 12
males with the mean age of 75.85 (age range= 61-82,
SD=5.32) and the mean length of education of 7.10 (SD=4.33),
3 of them were bilingual and 17 were monolingual and
all were in the mild to moderate stages of the disease
(mean MMSE=18.95, SD=6.18, MMSE range=12-27). The second
group, aphasic patients, consisted of 17 patients included
6 females and 11 males with the mean age of 66.82( age
range=60-78, SD=6.18) and the mean length of education
of 11.52 (SD=6.49), 8 of them were bilingual and 9 were
monolingual. The control group included 8 females and
12 males with the mean age of 67.25 (age range=60-82,
SD=6.21) and the mean length of education of 9.30 (SD=4.31).
Their mean MMSE score was 28.50 (MMSE range=25-30, SD=1.67)
and 8 were bilingual and 12 were monolingual.
As figure 1, healthy elderly
persons showed the highest and aphasic patients showed
the lowest correct responses to 50 items of the test.
As Kolmogorov-Smirnov test proved
the normality of data, T test was used for analysis.
T test revealed that there is a significant difference
in the mean scores of correct responses without any
cue between DAT patients and aphasic patients (p= 0.000).
Figure
1. Frequency of correct responses without any
cues in all three groups
CR.NOR = the number of responses without
any cues in normal group
Cr.ALZ = the number of responses without any cues in
DAT group
GR.APH = the number of responses without any cues in
aphasic group
Figure
2. The effects of different primings on eliciting
correct responses in DAT and aphasic patients
CRWS.ALZ = the number of correct responses
with semantic priming in DAT group
CRWS.APH = the number of correct responses with semantic
priming in aphasic group
CRWP.ALZ = the number of correct responses with phonological
priming in DAT group
CRWP.APH = the number of correct responses with phonological
priming in aphasic group
Table
1: Comparison of correct responses without and
with priming between DAT and aphasic patients
T test revealed significant difference (p = 0.000) between
the mean score of DAT and aphasic patients regarding
their reaction to semantic priming indicating a greater
effect in DAT patients (Table 1).Also it is apparent
from figure 2 that aphasic patients have shown a greater
effect in phonological priming than the other group
and T-test revealed that the difference is significant
(p = 0.000) (Table 1).
Figure
3. Comparison of overall performance of DAT and
aphasic patients in naming task
WR.ALZ = the number of wrong responses
in DAT group
WR.APH = the number of wrong responses in aphasic group
NO.R.ALZ = the number of no responses in DAT group
NO.R.APH = the number of no responses in aphasic group
TOR.ALZ = the total number of correct responses in DAT
group
TOR.APH = the total number of correct responses in aphasic
group
Figure 3 summarizes some of
the results obtained from the naming test .The number
of wrong responses in DAT patients were less than aphasics
which was shown to be significant (p< 0.05) by T
test (Table 2). Also aphasic patients showed more "
no response" than the other group and T test revealed
significane of this difference (p = 0.000) (Table 2).As
indicated in figure 3 total correct responses (the sum
of correct responses without any cue, with semantic
priming and with phonological priming) is higher in
DAT patients than aphasics which is proved to be significantly
different (p = 0.000) by T test (Table 2).
Table
2 Comaprison of wrong, no response and total
correct responses between DAT and aphasic patients
| Response |
test value
= 0t |
df |
Sig (2-tailed) |
mean difference |
95% CI lower |
95% CI Upper |
| WR.ALZ |
2.463 |
19 |
0.024 |
1.10000 |
0.1652 |
2.0348 |
| WR.APH |
2.324 |
16 |
0.034 |
4.2353 |
0.3726 |
8.0980 |
| NOR.ALZ |
4.893 |
19 |
0.000 |
4.0000 |
2.2888 |
5.7112 |
| NOR.APH |
3.005 |
16 |
0.008 |
10.2353 |
2.0153 |
17.4553 |
| TCR.ALZ |
47.893 |
19 |
0.000 |
43.8500 |
41.9337 |
45.7663 |
| TCR.APH |
10/.017 |
16 |
0.000 |
37.4118 |
29.4943 |
45.3293 |
WR.ALZ = wrong responses in
DAT group
WR.APH = wrong responses in aphasic group
NOR.ALZ = normal responses in DAT group
NOR.APH = normal responses in aphasic group
TCR.ALZ = total correct responses in DAT group
TCR.APH = total correct responses in aphasic group
DISCUSSION
Naming is a mental process requiring
representations of semantic, phonologic and morphosyntactic
information of our mental lexicon. Many neurologial
conditions including neurodegenerative diseases such
as Alzheimer's disease and acute brain lesions leading
to aphasia bring about confrontational naming deficits
in their victims which are much different by nature
and would be a way to understand brain cognitive mechanisms
in terms of language processesing.
As Chiarelli mentioned, "
Indeed, the peculiar pattern of linguistic and cognitive
deficits in early Alzheimer's disease, whereby memory
limitation and failure in semantics prevail over deficits
on syntax, makes an interesting contrast with linguistic
deficits in classic aphasia categories"(Chiarelli,
2006).
The results of the present study
showed that ther are many differences between the performance
of 3 groups of healthy elderly individuals, patients
with DAT and aphasic patients.In fact our normal aged
group showed no deficit in the confrontational naming
task which is consistent with the finding of Goulet,
Ska, and Kahn who showed that picture-naming accuracy
dose not decline with advancing age (Goulet et al.,
1994). There was a significant difference in correct
responses without any cue between DAT and aphasic patients.
DAT group had better performance in naming compared
to the other. Also total naming performance including
the total wrong responses, no responces and total correct
responses showed a better status for DAT patients compared
to the aphasic patients. These findings by no means
indicate a good naming performance on the part of DAT
patients but recognize and emphasize on anomia as a
universal symptom of aphasia.
The main finding of this study
is the recognition of differential stimulating power
of semantic and phonological priming in word retrieval
abilities of these 2 groups. DAT group benefited much
by semantic cues whereas the aphasic patients enjoyed
better from phonological primings. This study confirmed
the findings of the previous researches that phonological
cues are the best priming stimuli in aphasia, but the
word retrieval problems of DAT patients are related
to semantic memory deficits, and so they are more dependant
on semantic cues for better naming performance. As Wingfield
and colleagues outlined when an aphasic person is unable
to name an object, giving the the patient the initial
sounds of the target name will often trigger the correct
response (Wingfield et al., 1990). Also, it has been
suggested that aphasic anomia originates from a difficulty
in accessing the formal lexical representation and not
from a semantic problem (Le Dorze & Nespoulous,
1989).
It seems that.phonological primes
have a consistent facilitatory effect on aphasic picture
naming (Wilshire & Saffran, 2005), but word retrieval
problems of DAT patients are attributed to semantic
memory deficits, so that it may be a valid determinator
of predementia Alzheimer's disease (AD). It has been
shown that impairments on semantically related tests
are common in mild AD and may exist prior to the clinical
diagnosis, hence assessment of semantic memory could
be relevant in the evaluation of patients with suspected
AD (Vogel et al., 2005). The research body investigating
multilayer processes involved in naming from concept
to phonems use different neurological conditions such
as aphasia and progressive dementias to be able to see
a slow motion, scanned picture of what happens in an
extraordinary rapid mental stream called naming and
has led so far to the development of lexical retrieval
modles with theoretical and clinical applicatios.
CONCLUSSIONS
OBS in hospitalized older people
is common and frequently diagnosed late. It has a varied
presentation. The attending Medical Officers and Trainee
Specialists need to consider this great heterogeneity
when caring for patients, and when considering this
syndrome. We possess more questions than answers at
this moment but the fact that so many questions are
being asked proves that brain diseases in the elderly,
acute and especially chronic, are no longer the neglected
backwaters of neuropsychiatry. The importance of these
disorders, in both numerical and personal terms, is
being appraised in an increasing manner and is reflected
in the advances that have already been made. Their recognition
as diseases, and not inevitable concomitants of aging,
should be a harbinger of improved treatment, and perhaps
even of prevention.
ACKNOWLEDGEMENT
This project has been benefited
of the financial and scientific support of Iranian Research
Center on Aging. The authors are thankful of Mrs. Soheila
Hejrati, Mrs. Marzieh Amrovani, Mrs. Mitra Soltani and
Dr. Lili Hayati for their help in different stages of
the study. And also appreciate the help of Iranian Alzheimer
Association and consider theirselves indebted to all
patients, their families and also the healthy elderly
who participated in this study despite all difficulties
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