Lexical errors in narrative discourse of a bilingual subcortical aphasic- ISBA 10
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Lexical errors in narrative discourse of a bilingual subcortical aphasic- ISBA 10

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The above study is being presented at International Symposium on Bilingual Aphasia at AIISH, Mysore India 2010.

The above study is being presented at International Symposium on Bilingual Aphasia at AIISH, Mysore India 2010.

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  • 1. Lexical Errors in Narrative Discourse of A Bilingual Subcortical Aphasic Sudheer Bhan *, Sonal V Chitnis** Hyderabad Central University, India*, Yashoda Hospitals, Hyderabad, India**. ABSTRACT Subcortical Aphasia is defined as a language disorder associated with damage to subcortical brain structures such as basal ganglia, thalamus, and deep white matter pathways. It is predominantly seen in ischemic strokes patients. Clinical picture of subcortical aphasia is of great interest to researchers as it varies according to lesion site and is also difficult to categorize into fluent or nonfluent categories due to its typical speech & language features. Many studies have focused light on role of subcortical structures in language processing. Present study analyses lexical errors in narrative discourse of a bilingual (Telugu-English) speaking subcortical aphasic, following an acute subcortical ischemic stroke. She was assessed on Western Aphasia Battery (Kertesz 1985, translated Telugu version) and Addenbrooke’s Cognition examination revised (ACE-R 2007-Telugu version). Results showed frequent semantic and phonemic paraphasias. Patient reflected a typical subcortical aphasic syndrome presenting both fluent and nonfluent characteristics of aphasia. In naming verbs of motion, patient had dynamic misnaming. Empty speech, circumlocution,groping behavior, semantic confusion, and neologism were also observed.
  • 2. Lexical Errors in Narrative Discourse of A Bilingual Subcortical Aphasic INTRODUCTION Bilingualism or the alternate use of two or more languages is an integral part of globalization and social mobility. Mcnamara(1967a) proposes a minimal competence in one or more of the four language skills ,i.e. listening ,comprehension, speaking ,reading ,writing in a language other than mother tongue. Whether Bilinguals two languages are organized partly in common areas and partly in specific and separate areas of the brain is not completely proved. However, some studies have found that bilinguals have areas where stimulation could interrupt naming in a first language ,a second language or both (Ojemann and Whitaker,1978) This lends support to the view that each language is processed by partially overlapping areas. Paradis(1994) postulated that the mother tongue or L1 and L2 of a bilingual may rely upon different memory systems. Mother tongue relies upon implicit memory or procedural memory, which is related to automatic processes, completed within nominal awareness, whereas L2 depends upon explicit memory or declarative memory, which involves controlled processes carried out at conscious level. While, implicit memory heavily relies on subcortical structures like the basal ganglia , the cerebellum as well as left frontal lobe. Explicit memory relies mainly on widely distributed cortical network (including bilateral temporal lobe structures). As these memory systems employ different cerebral pathways, Bilingual’s L1 or L2 may be selectively affected by different pathologies. This results in different types of recovery patterns in Aphasics. Aphasia has been classically considered a consequence of cortical lesions. However, neuroimaging techniques in monolinguals and bilinguals have revealed that aphasia may also
  • 3. occur after lesions confined to Thalamus, the Basal ganglia or paraventricular white matter. Such aphasias are known as subcortical aphasia. While, subcortical aphasia in monolinguals is well known, only few cases of bilingual subcortical aphasia have been reported. Hence, present study on Lexical errors in Narrative Discourse in Bilingual Aphasic in Indian Context is relevant. Subcortical aphasia due to Thalamic lesions is known as thalamic aphasia. This Syndrome shares some features with Transcortical sensory and tanscortical motor aphasia. A relatively fluent output with semantic paraphasias and word finding deficits, intact repetition abilities and spared auditory comprehension are the main features of Thalamic aphasia. Subcortical aphasia following basal ganglia damage is often characterized by expressive and Lexico-semantic impairment generally consisting of nonfluent output with semantic and verbal paraphasias. It is caused by hemorrhages and infarctions. However, pure Subcortical Aphasias have been rarely reported. Most of the Subcortical Aphasias result from subcortical as well as cortical region network(e.g. disruption of fronto-Thalamic network). But, lesions in cortical regions are not usually visible in case of subcortical Aphasia through neuroimaging techniques. Present Subject had a left basalganglionic infarct with C.V.A. The subcortical aphasias can be classified into 3 types:1) Aphasia with white matter pathway damage 2) Straiatocapsular aphasia 3) Thalamic aphasia. Subcortical aphasics might show specific fluent or nonfluent feature. Anterior subcortical aphasias evolve into motor aphasia, whereas posterior lesions evolve into fluent aphasias. (Nasar et al., 1982) Repetitions are relatively preserved in subcortical aphasics (Andrew 2003) Initiation of speech is main problem in subcortical aphasia. Fabbro et al.,
  • 4. (2001) have reported that lesion in loop of caudate nucleus, globus pallidus, anterior nuclei anterior with cingulam cause difficulty in initiation of speech. The introduction of advanced neuroradiological investigation methods for lesion localization in vivo, including computed tomography and more recently magnetic resonance imaging (MRI), SPECT, PET have led to an increasing number of reports in the literature of aphasia following apparently purely subcortical lesions involving the striato-capsular region and/or thalamus. Consequently, in recent years, there has been growing acceptance of a role for subcortical structures such as the globus pallidus and thalamus in language processing. Many lesional studies have reported language disorders following damage of the basal ganglia in the dominant hemisphere, in particular speech apraxia and dysarthria after lesion of the lentiform nucleus and speech perseveration after caudate lesions. Most of these injuries, especially stroke, involve not only the striatum, but also the surrounding areas such as the capsulo-thalamic structures. Subcortical aphasia is also evident in patients with Parkinson’s disease, Huntington’s disease, etc. REVIEW OF LITERATURE Alexander (1987) studied 19 subcortical aphasics. He observed that lesions in the putamen or head of caudate nucleus did not produce language disturbances. They just caused mild word finding difficulty. Lesions in posterior putamen resulted in hypophonia. Lesion in caudate nucleus, putamen and anterior limb of internal capsule resulted in anterior subcortical aphasia. Lesion in white matter of periventricular region or genu of the internal capsule resulted in dysarthria. Fluent aphasia, neologism, impaired comprehension were found when there was lesion in basal ganglia converging on the temporal isthemus. Lesions in insula, internal capsule resulted in fluent aphasia, mild word finding difficulty and phonemic paraphasia. Longworth C E. et al (2001) studied the rule governed language use among subcortical aphasics with Parkinson’s disease and Huntigton’s disease. He reported small number of repetition, substitution and regularization errors (dug-digged). Mild Parkinson’s
  • 5. disease patients made relatively few errors - stached – satched- where phonology of the verb was distorted. Moderate Parkinson’s disease patients had correctly inflected phonological distortion and lexical intrusion errors for novel words. Mild Huntington’s disease had only over application of the - ed inflections. Moderate Huntington’s disease group made relatively few regularization errors and no multiply suffixed errors in their first responses. Results concluded that subcortical aphasics with basal ganglia dysfunction have intact automatic processing of syntax in language comprehension into the morpho-syntactic domain. Metter et al., (1988) focused on subcortical aphasia and role of basal ganglia in language. Their evidence was derived from CT scan, PET studies on stroke patients. Interesting findings were that fluency deficits were associated with basal ganglia, thalamus, internal capsule with deficits in phrase length, variety of grammatical constructions, as well as presence of jargon, word finding difficulty and circumlocution. Demeurisse.G (1995) studied the contribution of functional imaging techniques in subcortical aphasia. He found that sufficient cortical dysfunction gives rise to language disorders. He also reported evidence of Hypophonia ( loss of volume), reduced verbal output, jargon speech and phonological disorders. Mega, Michel et al. (1997) studied 14 patients with aphasia after subcortical lesions and controlled for duration, general anatomic site of lesions (capsulostriatal only), and etiology. They found the clinical profiles of the patients were quite similar, varying in severity in rough proportion to lesion size and varying in quality in proportion to anterior paraventricular extent. Large lesions were associated with impaired "executive" and "generative" language functions. Gurd, J.M. and Bannford, J.M. (1997) studied the cognitive impairment in two women subcortical aphasics. Both had circumscribed infarcts to the basal ganglia and internal capsule. The lesion in case 1 extended into the head of the caudate nucleus, whereas in case 2, it did not. Cognitive recovery was more rapid and complete in the second case, despite persistent impairment of the right hand. Both cases showed reduced blood flow in the left basal ganglia and fronto temporal regions at 6 months post onset.
  • 6. Nadeu, Stephen E & Crosson, B. (1997) in their review of earlier studies found no aphasia in 17 cases with dominant hemisphere straito capsuler infarction. They came across almost all patterns of language impairment in 33 reported cases of straito capsular infarction. It provides strong evidence against a major direct role of the basal ganglia in language and against disconnection or diachisis as mechanism of non thalamic subcortical aphasia. They also found that cases of C.V.A leading to straito capsular infarction strongly suggest that associated linguistic deficits are predominantly related to sustained cortical hypoperfusion and infarction not visible on structural imaging studies. Thalamic disconnection due to straito-capsular infarcts with extension to the temporal stem and putamenal hemorrhages may also contribute to language deficits in some cases. Disruption in attention gating in the pulvinar and lateral posterior nuclei resulting from such lesions may impair selection of specific neuronal networks in the projection field of these nuclei that serve as the substance for lexical semantic function. Demonet, Jean Fracois et al( 1991) assessed regional cerebral blood flow( r CBF) in 14 subcortical aphasics and 23 normal volunteers. In the subcortical aphasic group, the severity aphasia score was correlated with rCBF ratios in three left cortical regions and in a right posterior temporal region. Phonological disorders were associated with a hypoperfusion in both left and right posterior temporal regions. The rCBF in these homologous regions were highly correlated and this correlation was more marked in the subcortical patient group than in the normal group. The study proposes that compensatory neural machanisms in these interconnected homologous areas account for preserved comprehension capacities in many cases of subcortical aphasia, especially the thalamic cases. Aglioti, S et al (1996) reported neuropsychological and neurolinguistic features of a bilingual subcortical aphasia involving the left basal ganglia. A linguistic deficit in mother tongue production has been observed in spontaneous speech and in cross-language translational tasks which require automatized motor and cognitive performance respectively. She had more difficulties while translating into her second language. The study reflects the role of basal ganglia in automatized motor and cognitive performance.
  • 7. RELEVANCE OF STUDY Since there are very few studies carried out on subcortical aphasia in India in general and in Telugu language in particular. Hence present study – a single case study will shed more light on lexical errors in subcortical aphasia in Telugu-English biligual at narrative discourse level. OBJECTIVES OF STUDY To study the lexical error patterns in the narrative discourse of Telugu-English subcortical aphasic. METHODOLOGY:Subject - M, a 67 yr old is a right handed Telugu English bilingual woman. She was found unconscious in bathroom following cerebro-vascular stroke. She was shifted to NIMS hospitals, Hyderabad . Neurological examination revealed disorientation, loss of speech and complete right sided hemiplegia with facial deviation. M had always been healthy,. She was a social worker with graduate level education . She was proficient in both Telugu and English languages. She had no H/o diabetes, hypertension, CVA. She regained her consciousness after 2 hrs in hospital. During hospitalization, the patient manifested hypersomnia, disorientation in time and space, mental slowness and loss of speech and memory. She was severely nonfluent and could answer in just yes or no. MRI revealed left basalganglionic infarct with CVA. EEG showed generalized slowing of electrical activity. After 4 days, patient became stable, oriented and thus discharged. Later she was shifted to Nursing Home, Hyderabad for further rehabilitative measures. Memory, speech
  • 8. and language deficits were still persistent. She had good comprehension, but verbal expression was impaired. She was referred for speech therapy after 15days post stroke . Speech and language evaluation findings 15 days post stroke : WAB (Western Aphasia Battery): Spontaneous speech- 6/20 (Information Content-3, fluency-3- low volume jargon, mumbling, empty speech and certain times automatic sentences e.g. “what’s that, don’t know” Comprehension-58/60 Repitition-74/100 Naming-14/100 Speech was hypophonic. Max phonation duration was 4 sec. AMR (alternate motor rate)5syllables per second .SMR (Sequential motor rate)-2sec. Perseverations and phoneme reversal pattern were predominantly observed in her speech. ACE-R (Addenbrooke’s cognition examination) revealed impaired attention, concentration, impaired working memory with short term memory deficits, very poor verbal fluency. Reading was relatively preserved . Orientation:Registration: Memory recall:- 4/10 3/3 0/3 Attention & concentration: - 1/5
  • 9. Anterograde memory: - 2/7 Retrograde memory: - 2/4 Verbal fluency:- Letter fluency- 1/7 Fluency for generating names of animals:- 1/7 3stage command:- 2/3 Reading: - 1/1 Writing: - 0/1 Language: - Naming: Comprehension:- 4/12 4/4 Repetition: - 2/2 Reading: - ½ Visuospatial skills: clock = Pentagon= 2 1 Visuoperceptual skills: 4/4 Delayed recall: 0/7 Recognition:- 2/7 MMSE~ 14/30 ACE-R ~36/10
  • 10. RESULTS AND DISCUSSION Following are the error patterns seen in the language of Bilingual (Telugu + English) subcortical Aphasic Phonemic paraphasias 1./Pasapu/ - /parapu/ (“turmeric”) 2. /tala/ - ‘head’ 3. /bred/ - / talapu/ ‘lock’ /bed/ ‘bread’ 4. Ceyi – teyi ‘hand’ W k Ɔ 5. W ts – Ɔ ‘watch’ ʌʌ 7. Pustakam – ‘book’ k d p ʌʌʌ 6. K t pa – u: stakam
  • 11. 8. /Pilichkuntaru/ – /tilichikuntaru/ ‘to inhale/ blow the air’ 9./ kostunaru/ or /k t cestunaru/ – /kotcestunaru/ 10. /gontu/ /ghantamu/ ʌ – ‘throat’ 11. /aratipandu/ – / atripandu/ ‘banana’ M had several phonemic paraphasics in her speech. She substituted one phoneme for another [1, 2, 5, 6, 8], deleted initial phonemes in a word [7], deleted one of the phonemes from a consonant cluster [7], added an extra syllable to the target stimulus [2, 10]. Metathesis too was seen in two instances [11]. In (10), she wanted to say K nthamu; another name for ʌ gontu, but due to articulatory difficulty, she produced ‘ghantamu”, She also blended the form for verb ‘cut’ (koyi) in telugu with same form in English. Hence, came out with a word kotcestunaru [9] Neologisms Neologisms are totally new words produced by an aphasic in response to a target stimulus. They are not part of her native language 13. 14 . 15. /table/- /ye sak sak/ /ball/– dishti pandu ( semantic neologism) /boy/ 16. /Add m/ - / misen/ —/denti pula/ ʌ
  • 12. ‘Mirror’ When asked to describe a picture based on Boston diagnostic aphasia examination, she named a boy standing on a stool and trying to reach sweet box on upper shelf as misen. She named /dishti pandu/ for ball( 14) and /ye sak sak/ for table [15] a clear example of neologism. For /add m/, she named denlipula, again a neologism.(16). Later she came with ʌ target word- table as ‘pable’ an instance of phonemic paraphasia. Semantic paraphasias 17./ iddaru pillalu/ (two children) — /rendu pillalu/ (two children) (animate) (inanimate) 18./ ba:tu/ (duck) --- /pilla:/ (child) 19./add m/ (mirror)—/pennu/ (pen) ʌ 20. /ten nunchi/---/ ten nundi/ 21. /yellow/—/blu ‘blue’/ M named /rendu/ ‘two’ instead of/ iddaru/ ‘two’ however, in telugu language, iddaru ‘two’ is used for animate objects like children, whereas /rendu/ is used only for inanimate beings ,this reflects that M is not able to differentiate between animate and inanimate terms (17) similarly, she uttered nundi ‘from this (place)’ in place of nunci ‘from this (numeral etc). It again reflects that she is not able to differentiate these two case relations, referring to place and thing [20] .In (19) & (21), M named semantically unrelated paraphasia for the target stimulus. M named pilla( ‘child’) for batu( ‘duck’) probably, she was referring to young one of a duck, but could not name it. However, when investigator provided a phonemic cue |d| in English, she was able to name duck.
  • 13. Dynamic misnaming (22) gali patam egrestunnadu – gali (air) ….. ‘gali patam cestunadu’ ‘(He) is flying a kite’ ‘is doing a kite’ (23) gali pilichkuntadu – gali tilicukuntadu ‘He is blowing the air’ ‘air + phonemic paraphasia (balloon) (24) palu pongya:i – palu khinda padipoindi ‘The milk spilt’ ‘The milk fell down’ M named first air with phonemic error in verb naming and then ‘is doing kite’ instead of flying kite(. ) .Here, she has uttered a general verb for a specific one [22]. Similar phenomena was seen in (23). In (24) she simplified the verb-spilling with falling down. Empty Speech (26) ekkada untaru miru – umm, edo untanu “where do you live” “umm, I am somewhere” (27) abba:yi emi chestunnadu – edo padipotuna:ru khinda “what is the boy doing” (28) “something is falling down” ekkad emi jaragutondi “What is happening here” – adi adi “that that”
  • 14. (29) aavida emi cestundi – edo ra:stundi, va:l amma edo postundi ‘what is she doing’ ‘something (she is) applying, something she’s Pouring ‘ When shown a B.D.A.E picture, where a boy is likely to fall down from a stool, M named edo ‘something’ is falling down instead of evaro ‘someone’ [animate] is falling down. This indicates that she is not able to differentiate lexemes for animate and inanimate terms (27). In (26), instead of naming the place, where she exists, M uttered empty speech expression –e:do ‘somewhere’. In (29), where M was shown a picture revealing “a mother giving bath to a child”, M just said that mother is applying something to the child and pouring something, but could not name actual verb ‘bathing’ and object – soap. A similar empty speech phenomenon was also observed in (28). Groping behaviour (30) Wal ekkada unnaru – pa ……… ba …. intlo unnaru ‘where do they live’ …a…………. Amerika [after priming( phonemic cue)] (31) ivala emi tinna:ru miru – ‘what did you eat today’ (32) din emi antaru – --------‘What do you call that’ – beds n a: ….. ba - beds n … a: …ba okka … cinna illu ‘one …… small house’
  • 15. When investigator asked M about her children, she had severe word finding difficulty. After great struggle, she said – ‘they are in the house’, whereas the reality is that ‘they (children) reside in U.S.A (Amerika). However, when investigator prompted her with a phonemic cue – a.a.., she finally named amerika [30]. She could not name completely her breakfast stuff and had to grope about a lot. Finally, she named half way [31]. Similar behavior was seen in (32) too. Groping behaviour is a universal phenomenon across all subcortical aphasics in their speech. It reflects their severe word finding difficulty. Irrelevant jargon (33) Kichan lo unnaru, vastu tisko pote tisko potunnaru, chesko pote chesko potunnaru…. “she is in the kitchen. Having taken a thing, takes it away, having done ,doing it….”. In this instance, M uttered a sentence, which was not relevant to the context. Semantic confusion (34) gajulu ekkada veskuntaru – kaluki – cetaki ‘where do you put on bangles’ ‘to feet – to hands” (35) gajulu – golsu ‘bangles’ ‘necklace’ Instance (34) reveals that M was not able to name ‘arms’ for wearing bangles. Instead, she named both – hands and feet., which indicates severe semantic confusion. Similarly, she could not differentiate bangles and necklace and named later for former [35] Circumlocution (35) em custunaru ‘What do you see (in the picture)’ bel pamp undi ‘There is a pump, (for filling air) in the bel’
  • 16. When shown a picture, where a boy is blowing balloons, she named that there is a pump for filling air in the balloon and named bel for baloon. Pump was not shown in the picture. Probably, she was trying to provide function of pump for a balloon and thus circumlocuting. (36) kurgajalu kostaru , dintoti – ‘With what you cut the vegetables’ metiki, ceyidani ki ‘ it is the one, with which we do {meti-neologism} When asked to name with what we cut vegetables, she uttered is it the one, with which we cut – meti.. In this instance, she named ‘doing’ instead of ‘cutting’ – a general verb for a specific one. It is an example of dynamic misnaming. At the same time, she was unable to name target stimulus katti ‘knife’ and provided a neologism in its place. Repetition (37) rayatu polani duntunadu – polani duntunadu “The farmer is ploughing the field” “ploughing the field” (38) atanu tiragi ravandam ledu – tiragi ravadam ledu ‘He did not return back’ ‘did not return back’ (39) merisevi anni bangaram kadu – merisevi bangaram kadu “all that glitters is not gold” “glitters is not gold” (40) indradhanasu - indra dhanu M could not repeat four syllable words, as reflected in (40). She also deleted the subject, while repeating longer sentences [37, 38, 39]. In another instance, she repeated debbai moodu ‘seventy three’ as lekbai mudu” neologism + three”.. Hence, she produced a neologism.
  • 17. LIMITATIONS OF THE STUDY: Since present study is a single case study based on limited narrative discourse, it doesn’t reveal all linguistic impairments in subcortical aphasics. In future, a further study based on several subjects and larger data can focus on the language impairment in subcortical aphasics at a larger level. As in presented case, functional MRI, SPECT could not be done, so mechanism of Diaschisis and cortical hypoperfusion remains questionable. Further studies based on neuroradiological aspects will make these mechanisms clear. CONCLUSION:Semantic and phonemic paraphasias were frequently observed in present study. The patient is a typical subcortical aphasic, reflecting both nonfluent and fluent characteristics of aphasia. In naming verbs of motion, patient had dynamic misnaming. Patient’s speech also shows empty speech, circumlocutions, and semantic confusion. These are reflective of word finding difficulty in her speech. The patient deleted initial subject of the sentence, while repeating longer sentences.
  • 18. REFERANCES Agliotti, S. (1997). The role of thalamus and basal ganglia in human cognition. Journal of neurolinguistics, 10, (4), 255-265. Alexander, M.P.et al. Aphasia after left hemispheric intracerebral hammorhage . Neurology 1980.30,1193 – 1202 Lorenzen B.& Murray L.(2008) The Bilingual Aphasia: A Theoretical and Clinical Review,American journal of Speech & Language Pathology,(17) , 299–317 Choi, J Y. (2007) Subcortical Aphasia after Striatocapsular infarction: Quantitative analysis of Brain perfusion SPECT using statistical parametric mapping and a statistical probabilistic Anatomic mapping. Journal of Nuclear Medicine. (48), 2,194-200. Demeurisse, G. (1997). Contribution of functional imaging techniques: the study of subcortical aphasia. Journal of neurolinguistics, 10, (4), 301-311. Fabbro, F., et al. (1997). Language disorders in Bilingual patients after thalamic lesions. Journal of neurolinguistics,10, (4), 347-367. Gurd, J.M., and Bamford, J.M. (1997). Striatocapsular Aphasia: contrasting cases. Journal of neurolinguistics, 10, (4), 325-346. Longworth, C.E., et al. (2007). The basal ganglia and rule governed language rules: evidence from vascular and degenerative conditions. Brain, 128(30), 584-596. Mega, M. S. and Alexander, M .P. (1994). Subcortical aphasia : The core profile of capsulostriatal infarction . Journal of Neurology, 44, 1824-1847. Metter et al, (1988). Subcortical structures in Aphasia. An analysis based on fleurodeoxyglucose, positron emission tomography. Archives of Neurology, 45, 1229-1234.
  • 19. Nadeau, S. E, Rothi L.J.G., Chapter 4: Rehabilitation of Subcortical Aphasia. Language intervention strategies in Aphasia and related Neurogenic Communication Disorders. 4th edition .Edited by- R. Chapey, pp: 457-514. Nadeu, S and Crosson, B. (1997). Subcortical Aphasia. Brain and language, 58, 355-402. ACKNOWLEDGEMENT We thank sincerely Dr A. Suvarna, Associate Professor, NIMS Hospital, Hyderabad, for providing subject and also for her kind support and guidance. We also thank Dr Jaydip Ray Choudhary, HOD Neurology, Yashoda Hospitals,Somajiguda, Hyderabad for his valuable suggestions and inspiration.