Roya Khalili, PhD, ABD1,2,3,4, Eva Kehayia, PhD1,2,3, Marc Roig, PhD1,2,4
1School of Physical and Occupational Therapy, McGill University, Montréal
2Montreal Center for Interdisciplinary Research in Rehabilitation (CRIR), Montréal
3Language and Communication Research Laboratory, Jewish Rehabilitation Hospital, CRIR-Laval
4Memory and Motor Rehabilitation Laboratory (MEMORY-LAB), Feil and Oberfeld Research Centre, Jewish Rehabilitation Hospital, CRIR-Laval, QCDOI: https://doi.org/10.5770/cgj.27.707
ABSTRACT
Background
While the benefits of exercise on cognitive functions have already been reviewed, little is known about the impact of exercise on language performance. This scoping review was conducted to identify existing evidence on exercise-induced changes in language performance in healthy aging individuals and adults with stroke or neurodegenerative conditions.
Methods & Results
Using the Arksey and O’Malley framework, 29 studies were included. Eleven studies in healthy aging indicated enhanced language performance, with 72.72% having significant improvement in semantic/phonological Verbal Fluency (VF) following exercise. Among 18 studies on older adults with stroke or neurodegenerative conditions, 11 reported better language performance, with 44.44% having significant improvement in picture naming/description and semantic/phonological VF by exercise. The seven remaining studies reported no significant change in language performance in persons with stroke or neurodegenerative conditions.
Conclusion
Overall, exercise interventions showed improvement in language performance in healthy aging, while selective enhancement was shown for language performance in persons with either stroke or neurodegenerative conditions.
Key words: language impairment, exercise interventions, healthy aging, neurodegenerative conditions
The American College of Sports Medicine(1) defines exercise as a “type of physical activity consisting of planned, structured, and repetitive bodily movement done to improve and/or maintain one or more components of physical fitness”. (2) In addition to the physiological benefits of exercise,(3) studies on the effect of exercise on several aspects of cognitive functions reported improvement in information processing, reaction time, attention in older adults,(4) and memory in young and older adults.(5) Some of these cognitive functions are mediated by frontal and prefrontal brain regions, which are also involved in different language functions.(6)
Language is subserved by adaptable language networks across several brain regions. Activation, coordination, and integration of complex functions of the linguistic system (e.g., the lexicon, semantics, morphology, and syntax) along with other cognitive functions/domains, such as memory, attention, speed processing, and inhibition, are operative during language performance.(7) Two common factors that can influence language performance are aging and neurological conditions. Aging triggers a set of physiological and neurobiological changes that produce cognitive changes leading to language alterations (e.g., difficulty in word retrieval). In addition, neurological conditions resulting in changes to frontal, temporal, or parietal cortices can affect language production and comprehension and attenuate verbal fluency or access to word features, (e.g., semantics, phonology, or syntax). This can result in disconnected barely meaningful speech, derailed stories, and inefficient yet extraneous conversations.
Verbal Fluency (VF) which is predominantly representative of language abilities,(8) refers to producing a series of words from a predefined category engaging frontal executive functions and working memory, strategic search, error control, and monitoring.(9) The two most common types of VF tasks are semantic, where participants are asked to generate words belonging to a specific semantic category such as “animals”, and phonemic, where they are asked to generate words beginning with a specific letter or phoneme. Difficulty in retrieving and remembering words can affect relaying main ideas observed in picture description in healthy aging(10) and older adults with neurological conditions.(11)
Picture description refers to expressing information about a single picture or series of pictures, and is commonly employed for eliciting narrative discourse samples from both healthy and clinical populations.(10,11) Picture description involves various linguistic features (e.g., semantics, phonology), and cognitive functions (e.g., selective attention and memory). Word-finding difficulty during spontaneous speech, picture description, or storytelling is one of the most prevalent cognitive and linguistic changes in healthy aging and older adults with neurological conditions. Lack of proper communication and fluent speech might lead to ineffective communication, resulting in difficulties in receiving appropriate care or potential self-isolation. Given that exercise can induce selective enhancement in the frontal brain region,(4,12) and this region plays a prominent role in language performance,(6,9) it is important to investigate whether exercise can affect language performance. This can help identify feasible and cost-effective adjunct approaches to promote healthy cognitive aging, delay normal age-related cognitive difficulties, and develop more efficient treatments for neurological conditions.
The premise driving research on exercise is that this intervention triggers neurophysiological mechanisms such as the release of neurotransmitters such as dopamine and serotonin, or changes in blood oxygenation levels in brain regions involved in cognitive processing. Exercise also showed to increase gray matter volume specifically in the hippocampus and prefrontal regions involved in memory, executive functions, and language processing.(13) These structural changes suggest that exercise can enhance neuroplasticity;that is to say, the ability of the brain to reorganize and restructure, especially in the hippocampal and prefrontal areas. Enhanced neuroplasticity by exercise was reported to be associated with better cognitive functions.(14,15) Improved cognitive functions, in turn, can facilitate performance in language tasks.
The literature in support of the benefits of exercise on information processing, memory, and attention has already been reviewed(5,14) with little attention on language performance in healthy aging and older adults with stroke or neurodegenerative conditions. A recent review of cognitive and linguistic effects of aerobic exercise revealed potential positive results on language performance post-stroke.(16) However, the studies included in the Mayer et al.(16) review addressed only individuals with stroke and aphasia while the effect that exercise may have on language performance in healthy aging as well as in stroke and neurodegenerative conditions is yet to be summarized. This scoping review was conducted to identify and synthesize existing evidence on the effect of exercise on language performance in aging adults without or with stroke or neurodegenerative conditions.
The scoping review methodology, as proposed by Arksey and O’Malley(17) and later advanced by Levac et al.,(18) was followed through five of the six binding stages outlined below. The last stage (Stage 6–Consulting with Experts), which is optional, was not conducted as one of the authors is an expert in language (E.K.). In what follows we describe the methodology and procedure.
The research question was: What is currently known about the effect of exercise on language performance in healthy aging and older adults with stroke or neurodegenerative conditions? We were also interested in identifying the language assessments used and the aspects of language performance targeted. This information can provide further insights on the effect of exercise on language performance highlighting more sensitive measures reflecting exercise-induced changes. We hypothesized that exercise can enhance performance on language tasks that place demands on linguistic processes and higher-level executive functions mediated by (pre)frontal brain regions like VF or naming tasks. Other language tasks involving more semantic processes, like picture description, may also benefit from exercise.
The authors who include an expert in neuro/psycholinguistics (E. K.), an expert in exercise science and sport medicine (M. R.), and their PhD student in Rehabilitation Science (R. K.), with the assistance of an expert medical librarian, selected 18 key search terms comprising variants of keywords for exercise and language. (For the keywords see Appendix A.)
Both Medical Subject Headings (MeSH) and keywords, including their relevant subcategories with truncation symbols and wild cards, were used for the search terms. A comprehensive search of the literature was performed on four databases OVID MEDLINE, PubMed, CINAHL, and Cochrane Library. A first search was performed in October 2018 and was repeated in April 2021 and in September 2022 by the first author (R. K) and a research assistant. In the first search, 207 studies were retrieved; the second search retrieved 252 studies; and the final search retrieved 283 studies. Additionally, the first author hand-searched the bibliographical references of the included studies to identify studies that might not emerge from the database search.
Studies were included if: 1) the full texts were published in English or French and had language performance as an outcome; 2) they were clinical trials, cross-sectional and single-case studies, as well as studies with a within-subject design, all exploring the effect of exercise interventions on language performance and/or cognitive function with at least one language component; 3) the studied populations were adults with mean age ≥45 years old with and without stroke or neurodegenerative conditions which can be accompanied by language limitations including stroke, Mild Cognitive Impairment (MCI), Alzheimer’s disease (AD) and other dementias, as well as Parkinson’s disease (PD). The specific age group was selected because most neurodegenerative conditions, such as AD and PD, have aging as their primary risk factor. (19) Also, the risk of incidence of stroke doubles after 45 years. (20) Neurological conditions, like multiple sclerosis, were not the focus of this paper as speech-motor deficits observed in such conditions are found to be heavily associated with a dysexecutive syndrome rather than a language deficit.(21)
Studies were also included if: 4) they used any type of exercise intervention such as cardiovascular and resistance exercise, with either well-defined exercise parameters (i.e., FITT= Frequency, Intensity, Time (duration) and Type), or evidence of significant exercise workload increases in volume and/or intensity; and 5) they used acute or chronic exercise protocols. Acute exercise refers to a single bout of exercise that is sufficient to induce a systemic physiological response, for example, an increase in heart rate and body temperature.(5,22) We defined chronic exercise as interventions lasting at least four weeks with training sessions performed at least twice per week.(23)
Studies were excluded if: 1) participants were children, adolescents, or young adults; 2) participants had developmental language disorders (e.g., primary language impairment, autism, and fragile X syndrome); 3) no evidence of significant workload increases in volume and/or intensity was provided; 4) exercise interventions required very low energy consumption and merely targeted balance, fall, or gait control that were not intense enough to induce a systematic physiological response and training adaptation; 5) exercise interventions were combined with other non-exercise interventions such as cognitive training, having potential confounding or facilitatory effects on language unless the effect of exercise alone could clearly be evaluated having a control condition; 6) published as non-experimental publications such as reviews; and 7) published as book chapters, dissertations, protocols, or conference posters. However, the reference lists of these documents were searched and relevant studies were considered.
The study selection process comprised three phases. First, the scientific references were imported into EndNote X9.3.3 (Clarivate, London) and duplicates were removed. Then, the list of the titles and abstracts of the 535 remaining articles was imported into the Rayyan platform (https://www.rayyan.ai/), and two reviewers (R. K. & E. K.) independently selected the eligible articles. 98.31% agreement was achieved for the full text (56 included, 470 excluded, and 9 conflicts). A third reviewer (M. R.) resolved the conflicts. Full texts of the final 56 studies were assessed for eligibility and 29 studies were finally selected based on the above-mentioned inclusion criteria. The study selection process is presented in the PRISMA flowchart (see Figure 1).
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Figure 1 PRISMA flowchart of the study screening process | ||
A data extraction sheet was created and included the title, year, place of publication, setting, abstract, purpose of the study/research question, study design, type, number, groups of participants, and the inclusion and exclusion criteria. It also included the studies’ intervention and control conditions, baseline and outcome measures, assessment times, as well as strengths and limitations (see Appendix B).
The findings of the 29 included studies were tabulated and categorized using the International Classification of Functioning, Disability, and Health (ICF).(24) This framework was selected to ensure uniformity between reviewers when categorizing the outcomes into the most relevant themes. Furthermore, using ICF codes offered a broader range of structures and functions where change could occur (see Appendix C). After reaching a consensus regarding the ICF codes appropriate for each outcome, data from the 29 studies were independently reviewed and tabulated by two authors for each article. The three ICF domains scoped here were: Body Functions including Specific Mental Functions, Functions of Cardiovascular Hematological, Immunological and Respiratory Systems, and Neuromusculoskeletal and Movement-Related Functions; Body Structures including Structures of the Nervous System; and Activities and Participation including Learning and Applying Knowledge, and Mobility.
Given the complex nature of language, integrating both general cognitive and purely linguistic processes, outcome measures were categorized on a continuum that comprised two types of domain assessments: 1) Measures primarily assessing linguistic functions (e.g., VF or lexical decision) both targeting the access to the mental lexicon in different modalities (production and recognition); ICF code b167–Mental Functions of Language was used; and 2) Measures assessing global cognitive functions with at least one language component (e.g., Mini-Mental State Examination (MMSE),(25) or Montreal Cognitive Assessment (MoCA),(26) both tests targeting several linguistic domains (e.g. semantics, lexical access); ICF codes b164–Higher-level Cognitive Functions and b144–Memory Functions were used, while b167 was also integrated.
The extraction tables were collated and all the ICF codes were validated by the first author. All three reviewers reached a consensus on the validation of the ICF codes. Analysis of the designated codes was performed after validation. A mapping of the ICF codes for the outcome measures was conducted using the D3 JavaScript library (https://d3js.org/) (see Figure 2). In Figure 2, the size of each circle depicts the frequency of codes attributed to the outcome measures. It is noteworthy to mention that to attribute the most specific code(s) to each outcome, we often used more than one code. For instance, we assigned b140–Attention Functions, b164–Higher Cognitive Functions, and b167–Mental Functions of Language to the Stroop task (see Appendix C).
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FIGURE 2 Mapping of ICF (2001) codes for the raw data | ||
The results are reported in the flowchart of the study selection (see Figure 1). Twenty-nine studies (21 studies from the first search in 2018, six and two studies from the second and third search in 2021 and 2022, respectively) met the inclusion criteria. In the following sections, we first describe the characteristics of the included studies and then the main findings.
The main characteristics of the included studies— design, population, intervention, outcome assessments, and findings—are briefly described in Table 1. Ten studies were carried out in the US, six in Brazil, four in Australia, two in Germany, and one each in Canada, the Netherlands, Sweden, Denmark, Finland, China, and Egypt, respectively. Most of the studies (62.06%, n=18) were Randomized Control Trials (RCTs),(12,27–43) nine within-subject,(44–52) one cross-sectional,(53) and a case study.(54) Among the included studies, 11 examined older adults without any neurological or neurodegenerative disease,(12,27,35,37–39,41,42,46,50,53) six assessed dementia and/or AD,(28,31,34,40,43,51) three PD,(45,47,54) two included individuals with stroke,(48,49) another five included individuals with MCI,(29,32,36,44,52) and two single studies on older adults with cognitive deterioration(30) and older adults with depression.(33) The mean age of the participants was above 65 in 22 studies, and between 48 and 65 in seven studies (see Table 1 for details).
TABLE 1 Summary of the included studies
Exercise interventions were chronic protocols, except for three studies in which acute protocols were implemented.(37,46,50) The exercise intensity was moderate to vigorous, varying between 40–85% Heart Rate Reserve (HRR) and 10–15 repetition maximum. One acute program applied 65% HRR;(50) one assessed the dose-response to 25-min cycling at 60%, 90%, and 110% anaerobic threshold;(46) and another compared 50–70% and 85–95% HRpeak.(37) Seventeen (62.96%) applied multimodal interventions consisting of either different exercise modalities or exercise adjunct to other therapies/training.(27,28,30–32,35,36,38,40,41,43,47–50,53,54) Eleven studies (37.03%) used one modality of exercise.(12,29,33,34,39,42,44–46,51,52) The duration of the intervention ranged from 20 to 90 min (mean ± SD: 48.67 ± 17.81), with a frequency from two to four days a week (3 ± 0.76) and spanned 6.5 to 48 weeks (15.66 ± 8.42).
Except for one case study,(54) all others had one control group maintaining normal activities or receiving usual health care. In some studies, control groups received multimodal training including resistance and stretching,(12,30) physiotherapy,(48) stretching exercises and language therapy,(53) stretching exercises,(29,37) aerobic exercises,(44,52) or cognitive training(38,41) at an equal frequency and duration as the intervention.
A summary of the language and cognitive outcomes of the studies is shown in Table 1. We found that 75.86% of the studies showed positive effects of exercise on language performance, but in only 65.51% of all studies this effect was statistically significant. An analysis of the positive effects of exercise on different language aspects showed enhanced semantic VF in 27.58% of the studies, and 17.24% reported improvement in both semantic and letter VF. Additionally, 13.79% of the studies reported positive effects in letter VF, and 17.24% of the studies reported better picture naming and description. In the following section, we review the intervention parameters and outcome measures. Then, we further discuss the effect of exercise on language performance and identify different language aspects—verbal fluency and picture naming—targeted in older adults.
All 11 studies including healthy older adults, that is persons without stroke or neurodegenerative conditions (n= 676, 565 females), indicated improved language performance including semantic and letter VF following exercise interventions (see Table 1).
The detailed language and cognitive assessments used along with the ICF codes(24) assigned to each tool are presented in Appendix C. Semantic and letter VF were both assessed in five studies.(12,38,39,41,42) Two studies assessed only Semantic VF(35,46) and one study assessed only letter VF.(53) One study did not specify the type of VF used.(27) An associative novel word learning task(37) and naming via the Boston naming tests(35) were measured. The cognitive and language assessments used in these studies were Hopkins Verbal Learning Test,(12) Immediate and Delayed Recall, Verbal Memory, or Word List recall,(35,41) Stroop Word Interference Test,(35,38,42,50) Digit Span Forward & Backward,(12,38,42) and MoCA or MMSE.(27,35,42)
Among the 18 included studies involving older adults with stroke or neurodegenerative conditions (n= 1403, 816 females), 11 studies (61.11%) reported improved language performance including picture naming/description and semantic and letter VF induced by exercise.(29–32,34,44,45,47,49,52,54) Of these, eight (44.44%) found a statistically significant improvement in VF and picture description,(29,31,32,34,44,45,52,54) improved picture naming in stroke,(49) and picture description and semantic VF in PD.(45,47,54) Studies involving older adults with depression,(33) stroke,(48) AD and/or dementia reported no significant change in semantic VF.(28,36,43,52) while one study showed deteriorated semantic VF in older adults with AD.(40)
Semantic and letter VF were assessed in seven studies. (29,31,34,44,47,52,54) Six studies assessed only Semantic VF,(28,30,32,40,43,51) and one study assessed only letter VF.(36) Cued picture naming,(49) picture description,(45,54) and picture completion(29) were also measured. A single study assessed only Addenbrooke’s cognitive Examination-Revised (ACE-R) in which VF, language comprehension, repetition, and naming were assessed.(46) The cognitive measures with at least one verbal component used in these studies were Word List, Story Recall, Immediate and Delayed Recall, Rey Auditory Verbal Learning Test, or Verbal Paired Associates & Logical Memory for Verbal Memory test,(28,29,31,34,36,44) Stroop Word Interference Test,(28,29,31–34,45,54) Digit Span Forward & Backward,(28,31,33,45,54) Visual Memory Span Forward & Backward,(31) AD Assessment Scale-Cognitive, Clinical Dementia Rating or other Brief Cognitive Examinations,(28,30,32,35,40,43,44,51) or the MMSE. (31,32,34,40,43,44,54) The number of language and cognitive assessments per population is shown in Figure 3.
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FIGURE 3 Language and cognitive assessments | ||
This scoping review aimed to identify the effect of exercise on language performance in healthy aging adults and adults with stroke or neurodegenerative conditions. In line with previous reviews assessing the effect of exercise on various aspects of cognitive functions(4,5,14) and language performance,(16) we found that exercise can have positive effects on language performance in the addressed populations, as evidenced by the improved performance on VF and naming tasks. However, findings were inconsistent for older adults with stroke and neurodegenerative conditions. In older adults with PD,(45,47,54) dementia,(31) mild AD,(34) MCI,(29,32,44) or cognitive deterioration,(30) exercise interventions could positively influence VF(29,30,32,44,47,54) and picture description,(43) while no significant change was observed in VF tasks for older adults at risk of(36) or with AD,(28,40,43,51) or with major depression disorder.(33) In people with stroke, naming(49) showed improvement following exercise, while VF(48) remained unchanged.
Research on language performance is largely based on the use of a variety of word processing and production paradigms susceptible to age-related changes including VF and naming tasks. Generating words for such tasks relies on different networks across interconnected brain regions within and between hemispheres that engage in several coordinated cognitive and linguistic processes.(55) The cognitive ability of selection, retrieval, and production of appropriate lexical items is mostly associated with frontal, prefrontal, and temporal neural substrates.(3,56) Verbal word planning and articulation depend on the interactions between the language dominant hemisphere’s lateral frontal cortex, including posterior temporal and parietal regions and more anterior regions, such as the inferior frontal, anterior insula, and the motor cortex.(57) Aging influences different cognitive domains and effortful executive processing such as inhibition or speed processing, mediated by the frontal and prefrontal cortices and required for VF.(6) Evidence indicates that exercise could improve cognitive and executive performance mediated by these brain regions.
Exercise programs have shown significant, but selective, benefits for cognition, with the greatest fitness-induced gains appearing in executive-control processes(4) mediated by frontal and prefrontal brain regions which are essential for word retrieval. Fluent verbal production demands the transmission process between the semantic–verbal memory and phonological processing of a word with the involvement of executive processes.(58) VF measures are considered to place comparable demands on linguistic processes and effortful executive processes(8,59) which were found to improve by exercise.(4) Both semantic and letter VF tasks require efficient verbal retrieval and recall, as well as self-monitoring, deliberate self-initiation, and appropriate inhibition of responses.(59) Like VF, naming also relies on executive functions while engaging visual perceptual-spatial functioning.(60) A meta-analysis(4) demonstrated that cardiovascular exercise had a large effect size (g = 0.68) on planning, inhibition, and scheduling effortful mental procedures involved in VF. In line with this, the present review showed that studies in healthy aging adults improved semantic VF,(12,35,39) letter VF,(41,53) or both VF measures,(27,38,43,46) and naming(27,50) following exercise.
Very few studies have explored the effects of exercise on language performance in older adults with stroke.(13) We found only two studies on exercise in post-stroke patients that investigated the effect of cardiovascular exercise on naming,(49) VF, and global cognitive functions.(48) One study showed enhancement in naming in post-stroke aphasia.(49) The other reported significant improvement in cognitive functions with no change in VF.(48) Hence, further investigation is required to evaluate the role of exercise in language improvement in post-stroke aphasia.
In this review, findings for older adults with neurodegenerative conditions were inconclusive. Several studies showed positive results in semantic VF in people with MCI,(29,30,32,44) PD,(47,54) and mild-to-severe dementia(29) following exercise. Other exercise programs showed no change in semantic or letter VF in people with AD or dementia,(34,40,43,51) or people with MCI at risk of AD.(36) Neurodegenerative conditions like AD or other types of dementia can impact visuospatial processing including semantic memory, which was shown to be minimally (g = 0.426) affected by exercise.(4,5) Another reason why exercise was less effective in people with AD or other types of dementia could be the existing degraded semantic store’s integrity reflected in the impaired semantic VF.(59,61,62) A meta-analysis of 153 studies with 15,990 participants(59) found that naming and semantic VF were considerably more impaired than letter VF in people with dementia of the AD type. Overall, alterations in the structure or content of semantic knowledge in people with AD and other types of dementia(61,62) might interfere with the effect of exercise on VF, especially on semantic VF. However, given that cognitive and language performance tends to decline in AD and other types of dementia,(63) maintained cognitive functions following exercise protocols can be considered beneficial in such conditions.
In recent years, a large body of research exists on the effect of both acute and chronic exercise programs on cognition. Acute exercise showed improvement in attentional and memory resource allocation, hence benefitting executive control function in young(64) and older individuals.(4) Better vocabulary learning, recall, and retrieval were reported as the result of acute cardiovascular exercise in young (20.5 ± 0.5)(65,66) and older adults (66.4 ± 4.6).(37) The within-subject acute exercise studies included in the present review also reported a significant improvement in VF, global cognitive functions, memory, and attention, as well as a reduction in reaction times, following 25 minutes of acute cardiovascular exercises in older adults.(46,50)
In addition to acute exercise, chronic exercise paradigms induced improvement in cognitive and executive functions(4) as well as VF.(12,38) Chronic cardiovascular exercise has been linked to increased grey matter volumes in the hippocampus and prefrontal cortex,(13) as well as improvements in the prefrontal white matter tracts.(67) The hippocampus and prefrontal cortex are both involved in memory,(68) executive functioning,(69) and language processing.(70) Additionally, hippocampus degeneration has been reported in healthy aging(71) and in the pathogenesis of a variety of neurological conditions including dementia and major depressive disorder.(72) It seems that most exercise-induced neuroplasticity effects are associated with changes in the frontal and prefrontal cortex(13) that play a pivotal role in executive functions and working memory processes(68,69) involved in linguistic processing.
Exercise-induced changes in the brain can promote neuroplasticity(73) which may also contribute to changes in the affected language networks.(74,75) Brain-Derived Neurotrophic Factor (BDNF) is a neuroplasticity biomarker that was found to be affected by exercise paradigms.(15) Studies using non-invasive techniques indicated that exercise may be able to stimulate neuroplastic mechanisms such as neurogenesis, and increased basal BDNF levels.(76) Consistent with this finding, two of the studies also reported changes in BDNF levels and improved naming(49) and cognitive functions(48) in people with ischemic stroke following eight weeks of aerobic exercise. While there is evidence showing exercise increases BDNF levels,(15,77) the association between peripheral BDNF levels and cognitive functions requires more investigation.
The extent to which exercise can influence cognition is thought to be modulated by exercise parameters (i.e., FITT) and the timing of outcome assessment relative to administrating exercise, among many other factors. In addition to exercise protocols and methodological factors, inter- and intraindividual variability could also be a critical moderator in the response to exercise aimed at improving language. McSween and colleagues(37) found that individuals with lower baseline word learning abilities appeared to learn vocabulary more effectively than those with better baseline word learning abilities following a single bout of moderate and high-intensity cycling.
To summarize, language tasks that place more demands on linguistic processes and effortful executive functions mediated by frontal and prefrontal brain regions(8,59) seemed to be more responsive to the effect of exercise.(4)
We identified several limitations in the present review. Studies often used cognitive measures that may not have been sensitive enough to best capture changes in the studied population. For example, in studies on AD and dementia, validated cognitive measures, such as the MMSE(33,34) or other brief cognitive batteries,(49) might not reflect exercise-induced changes.(78) Furthermore, most studies reported overall scores, especially on measures such as MoCA or MMSE, with no record of individual scores for each subcategory. This made the analysis of the impact of exercise on the language component(s) challenging. Overall, heterogeneity in the studied populations and outcome measures may have affected the magnitude of the observed effect and challenged the generalizability of the findings.
Examining the effects of exercise on language performance is a relatively new area of research and more research is needed on different language domains. More particularly, neuroimaging studies can further examine the interactive effect of the underpinning neural mechanisms of exercise-induced changes in language production per individual. Studying how the cortical activities change during language tasks following exercise can provide valuable insights into designing new exercise-based treatments.
This scoping review provides new evidence on the effect of exercise paradigms on language performance in aging adults with and without language impairment. However, it is still unknown if the amount of the effect of exercise on language performance is therapeutically meaningful for persons with stroke or neurodegenerative conditions.
Overall, comprehending, analyzing, and implementing effective interventions which are feasible, low-cost, minimal risk, and non-pharmaceutical require more in-depth research on exercise and neurocognitive functions.
Thanks to Jill Boruff (Medical Librarian at McGill University) and Lina Lanni for providing help with the search strategy and the search, respectively.
We have read and understood the Canadian Geriatrics Journal’s policy on conflicts of interest disclosure and declare that we have none.
The study was supported by a grant awarded to Eva Kehayia (Co-PI) from the Social Sciences and Humanities Research Council (SSHRC) grant [335/251/018, 2016-2022], Montreal, Canada.
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Correspondence to: Roya Khalili, PhD, ABD, Language and Communication Research Laboratory, Jewish Rehabilitation Hospital, 3205 Place Alton-Goldbloom, Laval, H7V 1R2, QC, Canada, E-mail: Roya.khalili@mail.mcgill.ca
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Canadian Geriatrics Journal, Vol. 27, No. 3, SEPTEMBER 2024