Complaints about Language Performance Not Always Correlated with Objective Cognitive Deficits in the Elderly

A team of researchers from the HSE Centre for Language and Brain and Mental Health Clinic No. 1 named after N.A. Alexeev examined the relation between subjective complaints about language function and objective language performance in elderly people with mild cognitive impairment. The study was one of the first of its kind to address both language and memory complaints through a comprehensive questionnaire. It was found that the severity of subjective complaints exhibited only a moderate association with actual performance in language tasks. More informative was the relative severity of complaints: participants in the study who expressed higher concerns about their language function compared to their memory faced greater difficulties with language tasks. A paper with the study findings has been published in Aging, Neuropsychology, and Cognition.

As people age, many experience difficulties in recalling words, constructing lengthy sentences, comprehending the meaning of grammatically complex structures while reading, and understanding spoken language. Such subjective concerns are particularly prevalent in cases of mild cognitive impairment, which represents an intermediate state between natural age-related changes and more severe disorders such as dementia.

Previous research in the memory domain indicates that the severity of subjective complaints may not accurately reflect objective reality. For instance, Austrian researchers found that only around 10% of elderly individuals with objectively confirmed memory impairment reported experiencing memory problems, whereas the remaining 90% of those with memory impairment did not perceive any issues and, as a result, did not express concerns. Most studies on this subject so far have focused on memory without investigating language-related aspects. However, it is widely recognised that metacognition, ie the ability to assess one's own cognitive performance, can vary across cognitive functions. Researchers of the HSE Centre for Language and Brain and Mental Health Clinic No. 1 named after N.A. Alexeev conducted a study to determine how informative subjective complaints about the language function really are.

The 'tip of the tongue' phenomenon, where one struggles to recall a familiar word, is a common complaint one can hear from individuals of any age. To some extent, this is entirely normal and can affect anyone, including younger individuals with high cognitive performance. Therefore, it is crucial for both scientific and healthcare purposes to accurately interpret such complaints, including whether, to what extent and in which cases they may indicate actual impairments.

Svetlana Malyutina
Co-author of the paper, Deputy Director, HSE Centre for Language and Brain

The study included 163 participants aged 55 to 93 attending the Memory Clinic rehabilitation programme. To assess the severity of subjective complaints regarding their language function, each participant was asked to complete a questionnaire, expressing agreement or disagreement with specific statements. Half of the statements pertained to language function, including phrases like 'I often experience tip-of-the-tongue moments' or 'When reading, I find it difficult to understand long sentences the first time, so I have to reread them.' The remaining half of the statements addressed memory concerns, such as 'I often forget where I have placed my belongings.' Memory complaints were included in the questionnaire as a control measure, aiming to verify whether performance on language tasks would be associated specifically with language complaints or with a broader range of cognitive concerns.

Additionally, each participant completed two language tasks designed to be sufficiently challenging to identify individual differences in performance. One task assessed word retrieval, requiring participants to name a word based on its definition. For instance, when presented with the definition of 'a device whose arrow points to the north,' participants were required to name the word 'compass.'

The second task involved grammatical analysis, requiring participants to read grammatically complex sentences and respond to comprehension questions. For instance, following the sentence 'An Italian woman invited a French woman to dinner every evening at a ski resort,' participants were asked, 'Who invited the other one to dinner?' with two possible answers, the correct one being 'Italian,' and the incorrect one being 'French.'

Statistical models were used to examine whether performance on language tasks, including the accuracy and speed of naming words, as well as the speed and accuracy of comprehending sentences, was correlated with the severity of subjective complaints. The researchers analysed language complaints, memory complaints, and the difference in their severity, ie how much more or less a participant complained about their language function compared to their memory function. The statistical models also took into account factors such as age, educational level, overall cognitive performance measured by the Montreal Cognitive Assessment score, and the estimated levels of anxiety and depression.

Subjective language complaints were statistically linked to only half of the language performance measures assessed by the tasks—specifically, the speed at which participants named words and the accuracy with which they comprehended sentences. The remaining two performance measures—the accuracy of naming words and the speed of reading sentences—did not show a statistically significant association with the severity of language complaints. 

These findings align with those from previous studies on memory: subjective complaints exhibit only a moderate association with actual cognitive performance. This is likely due to the fact that one’s evaluation of their own cognitive functions can be confounded by various factors, including emotional state and personality traits (such as a tendency towards anxiety or calmness, and high or low self-esteem).

At the same time, it was revealed that nearly all indicators measured by language tasks (three out of four) exhibited a statistical association with the relative severity of language complaints compared to memory complaints. In other words, if a participant expressed more complaints about their language function than their memory function, they were more likely to encounter difficulties in language tasks. This implies that, while participants may not have accurately gauged the absolute level of the difficulties they experienced, they were still able to discern which function was more affected.

The study leads to conclusions regarding the extent to which clinical work with elderly individuals experiencing mild cognitive impairment can rely on the presence or absence of complaints about their language function. According to the study findings, the relative severity of complaints about different cognitive domains, such as whether an elderly person complains more about memory or language, holds better predictive value. On the contrary, the severity of language complaints alone, without comparison to other cognitive functions, should be approached with caution. Even if an elderly person expresses concerns about their language function, their actual performance may still fall within the normal range. Conversely, the absence of complaints does not necessarily indicate a high level of performance on language tasks. Therefore, an evaluation by a speech-language therapist or neuropsychologist may be advisable for elderly individuals whether or not they express complaints about their language function.

In practice, our specialists frequently encounter language deficits in patients with mild cognitive impairment. Interventions such as neurocognitive training targeting the language function, among other things, can stimulate language production and comprehension, writing, reading, and counting skills—all essential for normal functioning in old age. Irrespective of the presence or absence of language complaints, the effectiveness of language function training has been confirmed through both psychometric methods and subjective assessment by our patients.

Viktor Savilov
Head of Department, Memory Clinic, Mental Health Clinic No. 1 named after N.A. Alexeev

IQ

November 30, 2023