J Neurogastroenterol Motil 2021; 27(4): 650-652  https://doi.org/10.5056/jnm21027
Cognitive Deficits Associated With Dysphagia in Patients With Dementia
Sun-Wung Hsieh,1,2,3,4,5 Hui-Yu Chuang,1 Chih-Hsing Hung,4,5,6,7,8 and Chun-Hung Chen1,2,3,4*
1Department of Neurology, Kaohsiung Municipal Siaogang Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan; 2Department of Neurology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan; 3Neuroscience Research Center, Kaohsiung Medical University, Kaohsiung, Taiwan; 4Dysphagia Functional Reconstructive Center, Kaohsiung Municipal Siaogang Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan; 5Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan; 6Research Center for Environmental Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan; 7Department of Pediatrics, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan; and 8Department of Pediatrics, Kaohsiung Municipal Siaogang Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
Published online: October 30, 2021
© The Korean Society of Neurogastroenterology and Motility. All rights reserved.

cc This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

TO THE EDITOR: Dysphagia is very prevalent but often under-estimated among patients with dementia. Dysphagia leads to dehydration, impaired functionality, malnutrition, respiratory infections, reduced quality of life, and increased mortality, which complicates dementia.1 Dysphagia can occur in different types of dementia and can be shown during the whole course of dementia.2 Despite this, there are limited studies discussing the role of specific cognition deficits on dysphagia in patients with dementia. Herein, we aim to investigate the cognition associated with dysphagia in patients with dementia.

We recruited patients with dementia in our hospital. Dementia was diagnosed by using the “National Institute of Neurological Disorders and Stroke (NINCDS)-Alzheimer’s Disease and Related Disorders Association criteria.”3 We administered demographic data and psychometrics for the subjects, including Mini-mental State Examination (MMSE),4 Cognitive Abilities Screening Instrument (CASI),5 Clinical Dementia Rating (CDR)6 and CDR-sum of boxes (CDR-SB).6 CASI comprises 10 sub-scales as follows, remote memory, recent memory, attention, mentality, orientation, drawing, abstract, judgement, fluency, and language. We screened the swallowing function for subjects with dementia by using “Eating Assessment Tool-10 (EAT-10).”7 We recorded the summation of scores to indicate the severity of dysphagia. We presented the demographic data and difference of dysphagia variables between very mild to mild dementia (CDR 0.5 and 1) and moderate to severe dementia groups (CDR 2 and 3). We calculated the correlation between cognitive variables and dysphagia variables by Spearman’s correlation test.

After excluding 44 from a total of 89 subjects due to incomplete cognitive and dysphagia assessment, there were 45 subjects (25 female, 55.6 %) with dementia recruited in our study. The mean age was 76.9 years old and there were 32 (71.1%) with very mild to mild dementia. There were 19 subjects (42.2%) with high risk of dysphagia (EAT-10 ≥ 3). Table 1 demonstrates the demographic data and showed no difference of age, gender, and dysphagia between the 2 groups. Table 2 demonstrates the correlation of cognition with EAT-10. CDR-SB, MMSE, and CASI showed no correlation with EAT-10. Only attention sub-scale was correlated with EAT-10 (r = −0.302, P = 0.044).

Table 1 . Demographic Data and Difference of Cognition and Dysphagia Between Very Mild to Mild Dementia and Moderate to Severe Dementia Groups

Demographic dataTotal (N = 45)Very mild to mild dementia
(CDR 0.5, 1)
(n = 32)
Moderate to severe dementia
(CDR 2, 3)
(n = 13)
Age (yr)76.9 ± 9.077.8 ± 8.874.6 ± 9.20.278
Gender (female)25.0 (55.6)19.0 (59.4)6.0 (46.2)0.419
MMSE11.3 ± 6.413.5 ± 5.66.0 ± 5.1< 0.001
CASI38.5 ± 22.646.3 ± 18.519.5 ± 20.7< 0.001
CDR-SB6.9 ± 4.34.6 ± 2.312.4 ± 2.5< 0.001
EAT-104.6 ± 6.53.3 ± 4.88.1 ± 8.90.084
EAT-10 ≥ 319.0 (42.2)11.0 (34.4)8.0 (61.5)0.094

CDR, clinical dementia rating; MMSE, mini-mental state examination; CASI, cognitive abilities screening instrument; CDR-SB, clinical dementia rating-sum of boxes; EAT-10, eating assessment tool-10.

Values are presented as mean ± SD or n (%).

P < 0.05, statistically significant.

Table 2 . Correlation Between Cognition and Eating Assessment Tool-10

Correlation resultsEAT-10
Age (yr)
CASI total score
CASI sub-scales
Remote memory
Recent memory

CDR-SB, clinical dementia rating-sum of boxes; MMSE, mini-mental state examination; CASI, cognitive abilities screening instrument; EAT-10, eating assessment tool-10; r, correlation coefficient.

P < 0.05, statistically significant.

We concluded no correlation between dysphagia and severity of dementia. We only observed the attention deficit was associated with dysphagia in patients with dementia. Dysphagia may develop during any course of dementia. Attention deficit is found to be associated with the impaired frontal connectivity in patients with subcortical ischemic vascular dementia and Alzheimer’s disease.8 Saito et al9 speculated a neural circuit responsible for swallowing indicating that the middle frontal gyrus serves as an association area between the insula (as a sensory center) and the primary motor cortex (as a motor center). The lesion in the primary motor cortex may cause buccofacial apraxia (BFA) and limb kinetic apraxia, which presented frequently in patients with dementia. Although BFA is related with severity of dementia, Michel et al10 concluded no significant association between BFA and dysphagia. Researches indicated the prefrontal cortex, containing the large part of middle frontal gyrus, involved in swallowing function in the higher cognition level. The prefrontal cortex integrates perceived sensory signals with motor commands. Dorsolateral prefrontal cortex, locating in anterior half of the middle frontal gyrus, performs not only self-awareness and attentional control but also executive control of working memory.

Overall, we conclude that the attention deficit was associated with dysphagia in patients with dementia. Further studies focusing on evaluation of attention profiles and functional connectivity between frontal lobe and swallowing may aid in optimizing therapeutic approaches in dementia.

Financial support

This study was supported by Kaohsiung Municipal Siaogang Hospital, Kaohsiung, Taiwan (S-108-008, Kmhk-104-035, Kmhk-108-033, S-108-009, and S-109-001), and Kaohsiung Medical University Research Center Grant (KMU-TC109B03).

Conflicts of interest


Author contributions

Sun-Wung Hsieh was involved in drafting the manuscript; Hui-Yu Chuang was involved in collecting data; Chih-Hsing Hung was involved in interpreting data; and Chun-Hung Chen was involved in the study design.

  1. Easterling CS, Robbins E. Dementia and dysphagia. Geriatr Nurs 2008;29:275-285.
    Pubmed CrossRef
  2. Alagiakrishnan K, Bhanji RA, Kurian M. Evaluation and management of oropharyngeal dysphagia in different types of dementia: a systematic review. Arch Gerontol Geriatr 2013;56:1-9.
    Pubmed CrossRef
  3. Dubois B, Feldman HH, Jacova C, et al. Research criteria for the diagnosis of Alzheimer's disease: revising the NINCDS-ADRDA criteria. Lancet Neurol 2007;6:734-746.
  4. Folstein MF, Folstein SE, McHugh PR. "Mini-mental state". A practical method for grading the cognitive state of patients for the clinician. J Psychiatr Res 1975;12:189-198.
    Pubmed CrossRef
  5. Lin KN, Wang PN, Liu CY, Chen WT, Lee YC, Liu HC. Cutoff scores of the cognitive abilities screening instrument, Chinese version in screening of dementia. Dement Geriatr Cogn Disord 2002;14:176-182.
    Pubmed CrossRef
  6. Morris JC. The clinical dementia rating (CDR): current version and scoring rules. Neurology 1993;43:2412-2414.
    Pubmed CrossRef
  7. Belafsky PC, Mouadeb DA, Rees CJ, et al. Validity and reliability of the eating assessment tool (EAT-10). Ann Otol Rhinol Laryngol 2008;117:919-924.
    Pubmed CrossRef
  8. Tu MC, Hsu YH, Yang JJ, et al. Attention and functional connectivity among patients with early-stage subcortical ischemic vascular disease and Alzheimer's disease. Front Aging Neurosci 2020;12:239.
    Pubmed KoreaMed CrossRef
  9. Saito T, Hayashi K, Nakazawa H, Ota T. Clinical characteristics and lesions responsible for swallowing hesitation after acute cerebral infarction. Dysphagia 2016;31:567-573.
    Pubmed KoreaMed CrossRef
  10. Michel A, Verin E, Hansen K, Chassagne P, Roca F. Buccofacial apraxia, oropharyngeal dysphagia, and dementia severity in community-dwelling elderly patients. J Geriatr Psychiatry Nurol 2021;31:150-155.
    Pubmed CrossRef

This Article



Aims and Scope