Post-stroke aphasia: Limitations of the Boston diagnostic aphasia examination

INTRODUCTION

Stroke is a major international public health issue, according to the World Health Organization (WHO). It is the leading cause of acquired physical disability, and the second leading cause of dementia and mortality (WHO: Stroke, October 2023). The sensory-motor sequelae of stroke have serious occupational and socio-economic consequences, especially in young people, including aphasia. Aphasia is a disturbance of the linguistic code, affecting the production and/or comprehension of oral and/or written language (National Institute for Science and Medical Research: Cerebrovascular accident. The leading cause of acquired disability in adults, 2019); (Order of Speech-Language Pathologists and audiologist: aphasia. https://www.ooaq.qc.ca) and there are several varieties of aphasia according to some authors.^[1,2] It is mainly caused by strokes, the frequency of which in 2015 was 49.4% in Togo. This pathology is at the root of a psychological and functional catastrophe for the subject and his or her family, which can lead to social withdrawal.^[3,4]

A speech-language pathology assessment is then essential to establish the diagnosis and determine the need for speech-language therapy (Order of Speech-Language Pathologists and audiologist : aphasia ; www.ooaq.qc.ca): (L’aphasie. https://www.ooaq.qc.ca). This requires the use of standardized tests, which may or may not be calibrated. Test administration takes into account the patient’s socio-cultural and linguistic context. The Protocole Montréal Toulouse (MT86) and the BDAE (Boston Diagnostic Aphasia Examination) are the reference tests most commonly used to diagnose aphasia in France^[5-7] and in Africa, more specifically in Togo.

The Boston Diagnostic Aphasia Examination (BDAE) is one of the most commonly used aphasia batteries. The latest edition has undergone major revisions since its initial publication in 1972, but evidence of its validity is lacking.^[7,8] Information on performance in the general population is, however, limited. Thus, many researchers in various countries are often faced with the difficulty of using tests developed in foreign languages and standardized for populations in other countries, particularly in the fields of neuropsychology and neurolinguistics. This prompted Brazilian, Spanish authors and health professionals to carry out several studies adapting these tests to their socio-cultural reality.^[9,10] Brazilian researchers analyzed the performance of a sample of the Brazilian population subjected to a translated and adapted version of the Boston Diagnostic Aphasia Examination (BDAE).

All these tools and tests used by Togolese speech and language therapists (SLTs) to assess patients are mostly imported, and therefore of occidental culture. This fact could therefore constitute a biasing factor in the objective diagnosis, resulting in an inefficient care plan for the patient. However, in Togo, few studies have been carried out on the limitations of these test batteries in the assessment of post-stroke aphasia patients. Our research question was whether the BDAE test items are suitable for assessing aphasic stroke patients. We, therefore, hypothesized whether around 80% of SLTs feel that the items in this test have limitations in the assessment of aphasic patients in our context. The general aim was to describe the limitations of using the BDAE test by SLTs in Togo in the management of stroke patients, with a view to making suggestions for adaptation.

MATERIALS AND METHODS

The study was carried out in Lomé, the capital and main city of Togo. It is located in the extreme south-west of the country, along the coast of the Gulf of Guinea. In demographic terms, Lomé was estimated to have a population of around 1.8 million in 2020. It is characterized by its extreme youthfulness, with the under-15 s accounting for 37.67%, the under-25 s for 57.74%, and the over-60 s for just 4.49%. Culturally, Lomé is a cosmopolitan capital where many languages are spoken, the main one being Mina.^[11] This was a descriptive and analytical cross-sectional study conducted over a 2-month period from June to July 2022. The target population of our study is all SLTs practicing in Togo, and the source population, SLTs practicing in Lomé in the public, private, and parapublic sectors, such as Lomé National School for Medical Auxiliaries. The non-probabilistic method using the reasoned choice technique was used to survey 35 SLTs in Lomé. Those who refused to participate in the survey were excluded from the study. We collected information from SLTs using a semi-directive interview technique. An interview guide was developed for this purpose and covered three themes: The use of the BDAE by SLTs, the difficulties encountered in administering it and unsuitable tests/items. The data were processed, analyzed, and entered into Microsoft Office 2019. Later, all data entered in the Excel file were transposed into STATA software to facilitate statistical realizations. The results were presented in the form of averages with standard deviations for quantitative variables and proportions for qualitative variables. Excel was also used to present the results and word to enter the entire document.

The statistical tests used are Chi-square for qualitative variables and Student’s T for quantitative variables. The Chi-square test is used to compare percentages between several independent groups, while the Student’s t-test is used to compare means with their variances or standard deviations between two groups with a normal distribution and a significant result was obtained if P-value is < 0.05.

RESULTS

We surveyed 35 SLTs out of 38 working in Lomé, representing a proportion of 92.11% with a 95% confidence interval. We noted a predominance of males, with a sex ratio (M/F) of 03.38. According to their experiences, more SLTs (28.57%) have between 9 and 12 years’ professional experience; 22.86% have been practicing for at least 15 years or more compared with those in the 0–3 and 6–9 age groups (17.14%). Few have professional experience between 3–6 (8.57%) and 12–15 (5.71%) years [Figure 1]. The majority of SLTs (82.86%) work in the public sector, compared with 17.14% in private and parapublic centers such as Ecole Nationale des Auxiliaires Médicaux de Lomé (ENAM-Lomé). The majority (91.43%) of SLTs use the BDAE to assess aphasic patients with a statistically significant difference (P < 0.05), in contrast, less than half (42.86%) use informal tools, only 14.29% of SLTs use the MT86. SLTs that use BDAE make heterogeneous use of it, so 48.57% use it infrequently. About 31.43% use it moderately frequently, and 11.43% use it frequently. Patients’ general condition, language barriers, and low level of education were identified by SLTs as barriers to BDAE use. Conversation and spontaneous language, verbal discrimination, picture naming, command execution, recitation, and singing were the items most unsuitable in our context, according to many SLTs [Table 1]. The items “cactus, clover, and cone” were raised by many more respondents as being unsuitable in 90% of cases. In the order execution test, the “floor” and “ceiling” items were the ones mentioned by respondents as unsuitable for Togo’s socio-cultural context. Most SLTs considered these four recitation items unsuitable for the Togolese context and all of them were convinced that the two singing test items were inadequate, as were the logic and reasoning items [Table 2].

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Figure 1:

Distribution of speech and language therapists by years of professional experience in Lomé in 2022.

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DISCUSSION

This discussion focuses on the following points: Achieving objectives, the limits of the study and the interpretation and comparison of the main results with other studies. The general aim of this study was to describe the limitations of the use of the BDAE by SLTs with a view to making proposals for its adaptation. The BDAE is a neuropsychological test designed to diagnose aphasia and related disorders. Developed by Goodglass and Kaplan in 1972, it can be used by neurologists, psychologists, SLTs, and occupational therapists.^[12] Several editions of the BDAE have been developed in the world and each nation adapts it to its own socio-cultural and linguistic contexts.^[8,9] The interview technique was the one used to collect data from the study population. However, only SLTs residing in Lomé were interviewed as such and are therefore not representative of all SLTs in Togo. This could bias the data and consequently the results and is therefore a limitation of our study. However, our results are very interesting and have enabled us to compare our data with those in the literature. The paucity of the general literature must be emphasized, as little research has been carried out on this issue. The second stage of our study would be the applicability of the proposals made by SLTs to the general population, to better adapt these tools to our socio-cultural context. In our study, we noted a predominance of men, with a sex ratio of 3.38, which contrasts with data in the literature.^[13,14] For some authors, speech therapy is a caring and supportive profession that generally attracts women such care jobs are predominantly held by women for socio-historical reasons, according to Hobson and Lister in 2002 and Poulin-Dubois in 2006.^[13,14] We can explain this male predominance in our study by the cohabitation of physiotherapy and SLTs schools. Many men choose physiotherapy as a physical profession when they sit the entrance exam and if the entrance examination to physiotherapy school does not work out for some candidates, they choose speech therapy by ricochet. What’s more, it’s a profession that’s little-known to the general public in our country because it is a new profession. The majority of SLTs (28.57%) had between 09 and 12 years’ professional experience in our study and this is a positive aspect. Indeed, a great deal of experience on the part of SLTs would enable them to judge the tests used and to identify any difficulties. Respondents use very significantly (P < 0.05) the BDAE more than the MT86 because, for them, the BDAE is accessible and comprehensive, and, it enables all aspects of oral and written language to be assessed. BDAE is straightforward in terms of assessing the level of language performance and the severity of language disorders, compared with other tests. Our data are similar to those of Detante O who reported similar results in Aphasia Handicap Score in 2012^[4] and Spreen and Risser^[15]. However, despite this accessibility, the BDAE was used with varying frequency by SLTs. In fact, almost half (48.57%) used it infrequently, while 11.43% used it frequently. This variable frequency of use is thought to be linked to limitations in the use of the BDAE, such as language barriers (46.87%), the low educational level of aphasics (68.75%), and the length of time taken to complete the test (18.75%). The authors report that education had a significant impact on most BDAE subtests. In their study, a stepwise regression model showed that education best predicted variance in BDAE scores with low (<15%) to modest (>17%) but significant (P < 0.01) ability.^[9,16] Akashi and Ortiz found that education had a different effect on performance for each of the language skills.^[16] Language barriers are difficulties encountered by the SLTs surveyed in our study because when the patient does not have the required skills to write or read, but has a facility of expression in French, only the oral domain can be assessed. As reported by authors, a limited command of written language therefore constitutes a failure to pass the test. The authors point out that language barriers have a significant impact on BDAE subtypes.^[9,17,18] SLTs are limited in their communicative interactions with their patients when they do not understand their local language. This obliges SLTs to seek out a mediator to promote exchanges with his patient, as confirmed by Moukrim, Gonzalez, Pereira and Ortiz.^[18-20] The authors reported that people with no formal education/illiteracy performed worse than people with little education in some language tasks of the Montreal-Toulouse Language-Brazilian battery, suggesting that each year of education has an impact on cognitive-language performance. In our study, the patient’s general condition was a difficulty noted by 80% of the SLTs because the aphasia is a consequence of stroke in 25–40% of cases so associated often with the bad general condition, as reported by the Ordre des orthophonistes et audiologistes du Québec and Balogou and Belo^[3] We report in this study that the duration of the BDAE test is a constraint for the respondents in most cases. Hence, the average duration of the BDAE, which is 90 min, prevents some SLTs from taking advantage of all its tests, as has been widely reported by Mohr, Courrier et al., Stefaniak et al.^[7,21,22] As previously mentioned, the BDAE consists of oral and written language tests. The majority of SLTs found that the verbal discrimination, recitation, singing, and picture naming tests were considered the most unsuitable in 96.87% of cases. They are difficult to apply in Togo’s socio-cultural context, because most standardized assessment tools are developed in a Western context. Several authors have reported that body part naming and handwriting mechanics scores decreased significantly in the low socioeconomic group.^[9,22] Our data concur with Alikekere’s work on the limitations of the BDAE in 2019 (Alikekere S. Study of test limits of Boston Diagnostic Examination of Aphasia [BDAE] in Togo, speech therapy dissertation; ENAM-Lomé; 2019. p. 56), those of Kore in his work on the limitations of MT86 in 2006 (Kore K A. Using MT86 in Togo: Assessment of the limits to the possibility of adapting part of the protocol; speech therapy dissertation; ENAM-Lomé; 2006. p. 63.), and those of Ezzedine in his work on the adaptation of the bilingual aphasia test (BAT) in 2017 (Ezzeddine N. Adaptation of the BAT [Version Courte] to Lebanese: Linguistic and psychometric data; Toulouse. 2017). Several items were raised by many respondents as being unsuited to our socio-cultural realities. Among these, we have the items “cactus,” “clover,” and “cone.” Our data are similar to the Alikekere data. Singing items such as “au clair de la lune” and “frères jacques” are not adapted as reported by Bouchard et al.^[23] and Biwu M.^[24] Indeed, the songs “jacques brothers…” and “in the moonlight...” are nursery rhymes that little French children learn as early as kindergarten but this is not the case in Togo. These songs are not widely known, even if a few have mastered the melody of the song “frères jacques...,” which is similar to that of the song “à l’école” taught to children as soon as they start school. These two songs therefore deserve to be adapted to Togo’s socio-cultural context. The BDAE tests need to be revised and adapted to our socio-cultural context. Other studies should be carried out among the population to apply the suggestions arising from this first study.

CONCLUSION

At the end of this study, we note that the BDAE is the tool most frequently used by SLTs to assess aphasic patients. On the other hand, professionals use it with varying frequency, most often due to difficulties in passing it on to patients. Their use is heterogeneous. Some use the tests exclusively, in full or in part, while others vary their use. We have identified four main difficulties faced by SLTs in using the BDAE: Language barriers, patients’ general state of health, patients’ low level of education, and the unsuitability of certain items. All these BDAE tests and items require adaptation for proper assessment. It is therefore essential that further studies be carried out on the population to apply these suggestions to a better management strategy for aphasic patients.