|Year : 2006 | Volume
| Issue : 1 | Page : 25-31
Profiles of language impairment in progressive nonfluent aphasia
PS Mathuranath, A George, R Mathew, PJ Cherian
Department of Neurology, Cognition and Behavioural Neurology Centre (CBNC), Sree Chitra Tirunal Institute for Medical Sciences & Technology (SCTIMST), Trivandrum - 695011, Kerala, India
P S Mathuranath
Department of Neurology, SCTIMST, Trivandrum - 695 011, Kerala
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Objective: To study language in noncaucasian patients with progressive nonfluent aphasia (PNA). To determine differences in the language impairment in PNA patients with and without early onset behavioral changes. Materials and Methods: Based on clinical evaluation, six PNA patients were divided into those with ( EB , n =2) and without ( NB , n =4) early onset (i.e., within 24 months from onset) behavioural symptoms of frontotemporal dementia (FTD). NB was sub-grouped as Moderate (language plus subtle cognitive dysfunction; n =2) and Mild (isolated language dysfunction; n =2). Language on the western aphasia battery (WAB) of NB was compared with that of EB and of the three groups were compared with that of controls. Clinical follow-up ranged between 24 and 60 months from onset. Results: Three categories were matched for the disease duration. Compared to controls, significantly (P <0.05) lower scores were seen for all three groups on WAB fluency, repetition and writing; for the Moderate and EB on reading, naming and comprehension; and for the EB alone on information content. Information content and comprehension were significantly lower for the EB when compared to the NB. Over comparable periods, the aphasia quotient of patients in EB declined by more than 30 points and in the Moderate by 3 points. Conclusions: PNA frequently shows behavioral features suggestive of FTD early in the course of the illness. Poor information content on WAB differentiates patients with early behavioral dysfunction from those without. The extent of language impairment is a function of the disease stage rather than of disease duration, suggesting thereby that the "initial 2 years of relatively isolated language disorder" criteria, while useful, may exclude some patients with PNA.
Keywords: Primary progressive aphasia, progressive nonfluent aphasia, semantic dementia, western aphasia battery
|How to cite this article:|
Mathuranath P S, George A, Mathew R, Cherian P J. Profiles of language impairment in progressive nonfluent aphasia. Ann Indian Acad Neurol 2006;9:25-31
|How to cite this URL:|
Mathuranath P S, George A, Mathew R, Cherian P J. Profiles of language impairment in progressive nonfluent aphasia. Ann Indian Acad Neurol [serial online] 2006 [cited 2020 Jun 2];9:25-31. Available from: http://www.annalsofian.org/text.asp?2006/9/1/25/22818
Primary progressive aphasia (PPA) is a rare focal degeneration of the brain with predominant involvement of language functions.,,,,,,,, Two clinical forms of PPA are recognized, progressive nonfluent aphasia (PNA) and progressive fluent aphasia (PFA)., In the early stages, patients with PNA show nonfluent spontaneous speech with syntactic errors, a late and minimal decline in nonverbal cognitive functions and a predominantly asymmetric involvement of the language dominant perisylvian region. Patients with PFA show profound anomia, breakdown of semantic knowledge and rapid progression to semantic dementia (SD). The topography of lesion in them predominantly involves the anterolateral portions of temporal lobe, often bilaterally. On the basis of this understanding, the PPAs are currently grouped as lobar degeneration syndromes under the rubric of frontotemporal dementia (FTD).
Mesulam et al. observed that the impairment was confined primarily to the language domain for a number of years in many of their patients with PPA, and suggested an initial 2 years of "relatively isolated language disorder" and "relative absence of deficits in other domains", as inclusion criteria for the diagnosis of PPA. In contrast to this, other investigators have reported clinically evident behavioural changes suggestive of FTD occurring much earlier in some patients with PPA, and feel that such cases should not be excluded.
Our objective is to determine if (a) the pattern of language impairment in PPA patients with early onset behavioral changes differs from those without early onset behavioral changes and (b) the language impairment in PPA is a function of the duration of illness.
Six right-handed patients with PPA have been seen in the Memory and Neurobehavioral Clinic at our center in south India, since the year 2000. Five of them are native speakers of Malayalam and one of Tamil, both being Dravidian languages spoken largely in south India.
They underwent routine clinical and neurological examination, hemogram, biochemical investigations and neuroimaging (structural and functional) and were administered the Malayalam ( n =5) or Tamil ( n =1) adaptation of the western aphasia battery (WAB). All received a diagnosis of PNA. Detailed neuropsychological testing included the mini mental status examination (MMSE), Wechsler memory test-revised (WMS-R) (logical memory component - immediate, delayed and recognition modules, digit span and designs), Trail Making (Forms A and B), verbal fluency (VF) test (Category - animals and initial letter - "pa" in Malayalam and "p" in English), hospital anxiety and depression scale (HADS), clinical dementia rating (CDR) scale and the Addenbrookes cognitive examination (ACE) which includes a 7-item address recall, 12-item confrontation naming, construction praxis and a brief language evaluation.
On the basis of the clinical history and examination, the patients were categorized into PNA with early onset of behavioural symptoms ( EB ) - if behavioral symptoms suggestive of FTD had developed within 24 months from the onset and PNA without early onset of behavioural symptoms ( NB ) . Cases 1 and 2 had minimal language dysfunction (confined only to expressive language) and unimpaired cognition on bedside neurological examination. They were considered as Mild cases of NB. In addition to profound expressive language impairment on clinical examination, Cases 3 and 4 showed subtle impairment on praxis and set shifting. They were classified as Moderate cases of NB. When they were last seen between 24 and 36 months from the onset of illness, all four patients in NB group were essentially independent on the activities of daily living (except for the constraints due to aphasia), had no behavioral abnormalities and did not qualify for dementia by DSM IV. Cases 5 and 6 had started primarily as expressive language impairment and remained so for the first 10 months of their illness. Between 10 and 18 months from onset, they progressed to have comprehension impairment and developed behavioral changes in the form of perseveration and inappropriate jocularity, suggestive of FTD. They were classified as cases of EB. All patients have completed between 24 and 60 months of follow-up from the time of disease onset, receiving evaluations at intervals of 6-13 months.
A brief description of representative cases from each of the three groups with a note on their performance on the WAB at first assessment is presented below.
| Case Reports|| |
Case 2: (Mild) . A 68-year-old male, native speaker of Tamil, fluent in English, presented with progressive word finding difficulty of 15 months duration. He had difficulty in naming simple objects (e.g., rubber-band, etc.) although he was well conversant with the use of these objects. He had no other cognitive or neurological complaints. He remained status quo at the time of his last follow-up 24 months into the illness. He continues to read newspapers and books in both Tamil and English and is independent on all the activities of daily living. His neurological examination was unrevealing.
Language profile : Although his speech was fluent in Tamil, there were occasional breaks in fluency due to his word finding difficulty and there were occasional syntactic errors in which he dropped the function word and retained the content words. His comprehension and repetition abilities were relatively preserved. His confrontation naming was better than generative naming. He was able to read aloud and perform matching tasks but made a few errors in reading-comprehension of complex passages. Copy writing and writing to dictation was normal. Spontaneous writing (picture description) was preserved except for occasional syntactic errors and inability to find the right word, as described in the spoken speech.
Case 3: ( Moderate ) . A 74-year-old native speaker of Malayalam, a writer and literary translator (English to Malayalam and vise-versa) initially experienced difficulty during translation work. His editors noticed that there were spelling and syntactic errors in the translations. Over time, his spontaneous speech also worsened and he had prolonged word-finding pauses and syntactic errors in both the languages. He never had neologism, pallilalia or paraphasias. About 18 months into the illness, he reported some difficulty with numbers. We first saw him 24 months into the illness. On neurological examination the only findings were reduced vigilance, impaired go-no go test and tests of kinetic melodies and mild impairment in orofacial and ideomotor praxis. At the time of his last follow-up (36 months into the illness) he reported difficulty with counting money and telling the time. He had stopped reading books and writing, had very little spontaneous speech, expressed most of his needs through grunts and gestures and reported some difficulty in comprehending complex news items while watching the television. He had no behavioral symptoms, personality changes or other cognitive symptoms. Other than the limitation posed by the aphasia he remained independent on all the activities of daily living.
Language profile : In Malayalam his speech was nonfluent with a paucity of function words. On auditory-comprehension, he made errors as the complexity of the task increased. Repetition was relatively preserved. Confrontation naming was good whereas he was unable to generate any name on the fluency task or on sentence completion. He was able to read simple sentences and perform matching tasks but was impaired on reading-comprehension of passages. His writing ability was profoundly impaired. He was unable to copywrite, write to dictation or write spontaneously. On follow-up (36 months after the onset of illness) he had somewhat deteriorated on all subtests of WAB except auditory comprehension.
Case 5: ( EB ) . A 55-year-old right-handed nun, a native speaker of Malayalam, good in spoken and written English, started with slowed speech, prolonged word-finding pauses and naming difficulty in both the languages. She had trained as a nurse and worked in a missionary hospital for 29 years and was described by her former colleagues as being very articulate. Progressively, the spontaneous speech became telegraphic with short, syntactically erroneous sentences. A psychiatrist in the hospital where she worked was following her up. One year into the illness she showed difficulty in comprehending long or complex conversations. The psychiatrist had noted profound problems with expression, subtle problems with comprehension and no problems with memory or behavior. As the illness progressed, she stopped reading the Bible and the newspapers and also stopped all efforts at writing. Between 14 and 18 months from onset her colleagues in the convent noted changes in her personality and behavior. She was irregular in going to the church, was easily irritable and needed to be coaxed to take her bath. We first evaluated her 24 months into the illness. On examination, she showed subtle impairment of judgment, lack of insight, poor kinetic melodies and was occasionally inattentive. Calculation was impaired and ideomotor apraxia was present. There was no neglect or visuospatial disorientation. Famous face recognition, simultagnosis and color matching were preserved. Frontal release reflexes were present. At the time of her last follow-up at 42 months since onset, she was profoundly demented, hoarded soiled clothes, was very withdrawn and had hyperphagia, especially for sweets.
Language profile : Speech was nonfluent and syntactically erroneous and she used perseverative utterances. When asked what her job was, her reply in Malayalam translated as, "Was working in... hospital. To me... since 29 years... started working there." Performance worsened on comprehension and repetition as the complexity of the tasks increased. On confrontation naming, she was unable to name the objects (e.g., tooth-brush, comb, etc.) but could pantomime. She had no ability for generative naming. Her reading comprehension of passages was poor but she was able to read small sentences aloud. Her matching ability was preserved. She had significant paraphasic errors on dictation and was unable to write spontaneously. Copy writing was preserved. On her second visit, her only utterance was telling her name. She was unable to perform any of the other subtests on the WAB.
| Results|| |
Results of language tests
The demographic parameters and the scores of the patients in the three groups and that of the healthy community based controls on the various parameters of the WAB are shown in [Table - 1]. The three groups did not differ significantly ( P >0.05) on age, education and duration of illness.
The cut-off score on aphasia quotient used for diagnosing aphasia on the WAB was 92.7. On the WAB in the native language [Table - 1], the EB group showed difficulty with comprehension of complex commands although they classified as Broca's aphasia. In contrast, those in the NB group qualified for anomia or transcortical motor aphasia. There was a progressive decline of scores on all components across the three groups. Compared to the controls, the Mild , the Moderate and the EB groups had significantly ( P <0.05) lower scores on spontaneous speech (fluency), repetition and writing (writing just failed to reach a statistical significance in the Mild group, P =0.054). In addition, compared to the controls, the Moderate and the EB groups had significantly lower scores on reading, naming and (all three subcomponents of) comprehension and the EB group alone had significantly low scores on information content as well. On naming, however, of the four subcomponents, object naming and sentence completion were unaffected in the Moderate group while affected in the EB group. When compared to the NB group as a whole, the EB group was significantly more impaired on information content ( P =0.04) and comprehension ( P =0.045). There was marked impairment on writing for Case 3 and on naming for Case 4.
Follow-up WAB in Native Language. Follow-up WAB was available for Cases 3, 5 and 6 at 11±2.6 months (12, 8 and 13 months, respectively) after first assessment. Case 3 showed mild decline of scores on all WAB subtests except fluency, information content and comprehension and a 3-point decline on aphasia quotient (70.2-67). He qualified for transcortical motor aphasia. Cases 5 and 6 performed at floor level on all the subtests and qualified for global aphasia. Their aphasia quotient had declined from 35.9 to 4.6 (Case 3) and 51.5 to 2.2 (Case 4). Follow-up WAB at 24 months from onset (i.e., 6 months after first evaluation) was also repeated for cases 2 and 4 and found to be essentially unchanged when compared to their baseline WAB.
Results on the neuropsychological and other tests
The scores on the neuropsychological tests are shown in [Table - 2]. The tests were divided into verbal and nonverbal and scores of a healthy community based control group ( n =10) was compared with each of the three patient groups. The Mild group did not show any significant difference on any of the verbal or nonverbal tests. The Moderate group showed subtle impairment on digit-span, confirming the subtle impairment of frontal lobe functions found on clinical bedside examination. Unlike the Mild group, the Moderate group showed significant differences in the scores on verbal components of the neuropsychological tests. The EB group was significantly impaired on both verbal and nonverbal tests.
None of the six patients had any abnormalities on routine hemogram and biochemical tests. MRI Brain of Case 1 was similar to that of Case 2 and of Case 4 to that of Case 3 [Figure - 1]. MRI Brain of Cases 1 and 2 showed a selective left perisylvian opercular atrophy involving the frontal and temporal operculum. Their SPECT scans showed reduced perfusion typically in the left temporal area. MRI Brain of Cases 3 and 4 showed a more generalized although asymmetrical atrophy involving the temporal neocortex and the frontal operculum maximally. Their SPECT scans showed reduced perfusion in the same areas. MRI Brain of Case 5 and the CT head of Case 6 showed diffuse and profound atrophy involving the frontal and temporal lobes bilaterally, maximally on the left.
| Discussion|| |
Most published series report that the majority of patients with PPA have nonfluent aphasia.,,,, All six of our patients had nonfluent aphasia at onset with relatively preserved comprehension and absence of any other cognitive impairment for at least 10 months from the time of onset of the language impairment. Three patients had onset of the illness in the presenium (46-55 years) and three developed in senescence (67-74 years). Two of them, both females, went on to develop behavioral symptoms typical of FTD between 10 and 18 months from the onset of the illness. The other four patients, all males, remain progressive aphasics at 24-60 months from onset, with little or no impairment of other cognitive domains.
The present study investigates the profiles of language impairment in different stages of PNA and in subjects with and without early behavioral symptoms suggestive of FTD. Depending on the degree of clinical involvement, the patients were divided into Mild (purely language impairment), Moderate (subtle impairment in other neuropsychological functions in addition to language impairment) and EB (language changes accompanied by behavioral changes of FTD). Thus, each subsequent group represented a more advanced stage of the disease.
The importance of the assessment of aphasia-independent intellectual skills cannot be underestimated in PPA. It has been a major problem, however, to create test batteries of cognitive skills that are not influenced by aphasia. Even nonverbal tests such as, Ravens colored progressive matrices have been shown to be adversely affected by both aphasia and apraxia. Investigation of the typical language profile was the primary objective of this study. In the present series, therefore, patients were included or excluded on the basis of the history and the clinical findings and the neuropsychological test scores were not used as a priori exclusion criteria.
The neuropsychological test results, however, were in line with the results of the bedside clinical examination that was used to sub-classify patients. While both the Mild and Moderate NB patients were comparable to controls on all nonverbal tests, the patients with behavioral changes (EB) had a significantly lower performance on all the tests, both verbal and nonverbal. The significantly lower performance of the Moderate patients on the verbal tests is an expected finding that is attributable to the profound impairment on expressive language functions whose integrity is essential for assessments on verbal neuropsychological tests.
Language in PPA
All patients in this study, irrespective of whether they developed early behavioral symptoms or not, had a similar onset of the disease. They started with word finding difficulty, syntactic errors and difficulty in expressing themselves, similar to what is reported commonly in PNA.,,,, Cross-sectional data from this study reveals that the three groups show increasing degrees of impairment on language functions. Fluency, repetition and writing are affected in all stages of the disease when compared to the controls. As the disease advances to cause subtle neuropsychological impairment beyond the language domain (Moderate stages), the comprehension, naming and reading functions also decline below that of controls. Nevertheless, in spite of this, these patients are known to maintain reasonably good communication ability at this stage., This is probably attributable to the relatively preserved information content and their other nonverbal communication skills. Our data also shows that the naming deficits in the Moderate group is mainly for more complex tasks of word fluency and completing a sentence, both of which are the more difficult subcomponents of naming. The relatively easier naming tasks like object naming and responsive speech are preserved at this stage. Impaired information content and comprehension differentiated the patients with early behavioral changes from those without such symptoms. It is also evident that the more advanced the disease, the greater is the extent of impairment on language. The longitudinal data in this study shows that patients with early behavioral symptoms suffered a much greater decline in language functions in a year when compared to patients without behavioral changes.
Given that the duration of the illness for the three groups was comparable, these cross-sectional and longitudinal data suggest that the extent of impairment in patients with PPA is more a function of the rate of progression of the disease than of the duration of the disease. It also supports the notion that PPA frequently shows behavioral features that are suggestive of FTD early in the course of the illness and that this evolution can be recognized on the basis of purely clinical data., These findings favor the view that while the criteria of "an initial 2 years of relatively isolated language disorder" serves as a useful guideline, it can potentially exclude some patients with PNA. It must be emphasized that the core feature in all these patients pertains to language and that the behavioral symptoms, if present, are neither in the forefront nor disturbing and on most occasions are reported by the carer only on leading questions. In contrast, in frontal variant of FTD, language affliction begins late and it is the behavioral problems that remain in the forefront bringing the patient to medical attention. Limitation of this study includes the small sample size and the absence of histopathological data. Given the fact that PNA is a relatively rare degenerative syndrome and that its diagnosis is based primarily on the clinical rather than histological findings, we feel that our observations, although on a small sample, make relevant contributions. Both our patients with early behavioral changes had developed these symptoms by the time we saw them. However, we were able to ascertain the course of their illness by contacting the psychiatrists, who had followed up these patients from the onset of their illness, maintained notes on the course of their illness and subsequently referred them to us. We could, therefore, confirm the isolated expressive language involvement and absence of any memory impairment in both the patients.
Finally, we conclude that PNA frequently shows behavioral features suggestive of FTD early in the course of the illness. Poor information content on WAB differentiates patients with early behavioral dysfunction from those without. The extent of language impairment is a function of the disease stage rather than of disease duration, suggesting thereby that the "initial 2 years of relatively isolated language disorder" criteria, while useful, may exclude some patients with PNA.
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[Figure - 1]
[Table - 1], [Table - 2]