Difficulty finding words or the habit of substituting them with others that are similar semantically – such as knife and cutter – or phonologically – such as knife and wife – are usually the first symptoms of a type of dementia known as primary progressive aphasia (PPA). Another sign is a subtle difficulty in forming sentences, evidenced by verbal and nominal agreement errors that have never been made before, or reversal of word order, for example. Writing errors (dysgraphia) and reading difficulties (dyslexia) may also occur, so that writing and reading become increasingly difficult tasks, as does expressing ideas and thoughts. Primary progressive aphasia is a rare and difficult-to-diagnose neurodegenerative disease that begins with language problems that affect communication and progresses to more serious cognitive changes that may resemble Alzheimer's disease or other types of dementia. The neurological diagnosis of this dementia syndrome requires a complete analysis that includes other cognitive functions in addition to language and communication problems. Now, a study supported by FAPESP and published in the journal PLOS ONE has shown that this condition can be detected early using a set of speech and hearing tests known as the Montreal-Toulouse Language Assessment Battery (MTL-BR). The possibility of early and more accurate diagnosis is great news because the earlier treatment is started, the slower the progression of the disease tends to be. The earlier the rehabilitation, the greater the chance that the patient will be able to maintain their communication, speaking, reading and writing skills for longer. But of course we're not talking about a complete diagnosis, just a part of the assessment that can allow us to identify patients who need more monitoring and attention." Karin Zazo Ortiz, professor in the Department of Speech and Hearing Therapy at the Federal University of São Paulo (UNIFESP) in Brazil and corresponding author of the article In the study, the researchers evaluated 87 individuals, including 29 diagnosed with primary progressive aphasia and 58 healthy individuals matched for age and educational level. "We compared the performance of participants with and without the syndrome on a large number of tasks involving different linguistic processes. As a result, we observed marked differences in some tasks, and at this stage of the work we were able to identify the most relevant tests among the 22 tasks that make up the MTL-BR battery," says Ortiz. As this is a very comprehensive and complete battery, the researcher says that identifying the key tests can help simplify the assessment, making preliminary detection quicker and more accessible. According to the results, the tasks in which patients with primary progressive aphasia performed worst on the MTL-BR were: directed interview, oral comprehension of sentences, oral narrative discourse, written comprehension of sentences, dictation, repetition of sentences, semantic verbal fluency, naming of nouns and verbs, manipulation of objects on verbal command, phonological verbal fluency, recognition of body parts and left-right orientation, written naming of nouns, comprehension of oral text, numerical dictation, comprehension of written text, and numerical calculation (mental and written). Ortiz explains that the battery of tests was chosen as the object of study because it provides a broad assessment of oral (speech) and written comprehension and production, as well as being the only validated test in Brazil for acquired language disorders of neurological origin. The research is now entering a new phase, which aims to identify the most important linguistic tasks for identifying each variant of the syndrome. Variants The partial or total loss of the ability to understand and express spoken or written language came into the spotlight in 2022 when Hollywood actor Bruce Willis was diagnosed with aphasia, which later developed into frontotemporal dementia. In the same year, Brazilian cartoonist Angeli announced that he was quitting his job because of the syndrome. Primary progressive aphasia is a different condition from aphasia, which can arise as a result of strokes, brain tumors and traumatic brain injuries. PPA belongs to the group of diseases known as dementias. It affects the frontotemporal part of the brain and is considered even more aggressive than Alzheimer's disease. Nevertheless, PPA is difficult to diagnose, mainly because the initial symptoms can be very similar to those of other dementia syndromes – although language impairment is much greater in relation to other cognitive domains. Another complicating factor is the heterogeneity of the cases. "Despite the importance of language in the differential diagnosis of neurodegenerative diseases, there's still a lack of language assessment tools for all types of dementia, including primary progressive aphasia," he says. To further complicate diagnosis, there are four subtypes of PPA. One is non-fluent or agrammatic primary progressive aphasia, which is characterized by changes in the syntactic structure of sentences, difficulty understanding complex sentences, and may be accompanied by apraxia of speech, in which the patient makes speech errors due to motor planning deficits. Another variant is semantic primary progressive aphasia, which is characterized by difficulty understanding words due to semantic impairment, anomia, and difficulty reading and writing irregular words. Logopenic primary progressive aphasia is considered to be more similar to Alzheimer's dementia and in these cases the patient has difficulty understanding long content and commits exchanges and omissions of sounds in speech. There is also mixed or unclassifiable PPA, characterized by language alterations in which a specific language profile cannot be identified because either the patients do not have the characteristics predicted for one of the variants or they have characteristics of several of the variants, making it difficult to specifically diagnose one of them. "And it's in this sense that our study contributes to diagnosis, as it allows early identification of changes in language, highlighting the differences between primary progressive aphasia and other dementia syndromes," says Ortiz.