Awareness of Dysphagia by Patients Following Stroke Predicts

Swallowing Performance

Claire Parker, MPhil,1 Maxine Power, PhD,2 Shaheen Hamdy, PhD,2 Audrey Bowen, PhD,3

Pippa Tyrrell, PhD,41 and David G. Thompson, PhD21Speech and Language Therapy Department, Hope Hospital, Salford, Manchester;2 2Department of GI Sciences, University of Manchester,

Hope Hospital, Salford, Manchester; 3Human Communication and Deafness Group, University of Manchester, Manchester; and4Department of Stroke Medicine, University of Manchester3 Hope Hospital, Salford, Manchester, United Kingdom

Abstract. Patients’ awareness of their disability afterstroke represents an important aspect of functionalrecovery. Our study aimed to assess whether patientawareness of the clinical indicators of dysphagia,used routinely in clinical assessment, related to anappreciation of ‘‘a swallowing problem’’ and how thisawareness influenced swallowing performance andoutcome in dysphagic stroke patients. Seventy pa-tients were studied 72 h post hemispheric stroke.Patients were screened for dysphagia by clinical as-sessment, followed by a timed water swallow test toexamine swallowing performance. Patient awarenessof dysphagia and its significance were determined bydetailed question-based assessment. Medical recordswere examined at three months. Dysphagia wasidentified in 27 patients, 16 of whom had poorawareness of their dysphagic symptoms. Dysphagicpatients with poor awareness drank water morequickly (5 ml/s vs. <1 ml/s, p = 0.03) and tooklarger volumes per swallow (10 ml vs. 6 ml, p= 0.04)than patients with good awareness. By comparison,neither patients with good awareness or poorawareness perceived they had a swallowing problem.Patients with poor awareness experienced numeri-cally more complications at three months. Strokepatients with good awareness of the clinical indica-tors of dysphagia modify the way they drink bytaking smaller volumes per swallow and drink moreslowly than those with poor awareness. Dysphagic

stroke patients, regardless of good or poor awarenessof the clinical indicators of dysphagia, rarely perceivethey have a swallowing problem. These findings mayhave implications for longer-term outcome, patientcompliance, and treatment of dysphagia after stroke.

Key words: Aspiration — Dysphagia — Stroke —Deglutition — Deglutition disorders.

Dysphagia is a common and distressing consequenceof hemispheric stroke, occurring in up to half ofpatients immediately after the event [1]. Dysphagiaafter stroke increases the risk of death, mainly as aconsequence of pneumonia which is implicated in onethird of stroke deaths [2], and worsens functionaloutcome post stroke, with slower recovery [3] andlonger hospital stay. However, despite similar dys-phagia severity at onset, individual recovery patternsvary widely. The reason for this remains unclear; inparticular, it does not appear to be directly related tostroke severity [4].

In most hospitals in the United Kingdom, thefeatures of dysphagia are identified by clinical as-sessment and only a small number undergo morespecific diagnostic procedures such as videofluoros-copy [5]. In most cases, therefore, it is the clinical as-sessment that determines the introduction oftreatment such as postural adjustment [6], swallowmaneuvers [6], alterations in food consistency [6], andfaucial arch stimulation [7]. While there is some evi-dence that these treatments improve nutritional statusin stroke patients and reduce airway complications[8], it is important to recognize that all of them requireconsiderable patient compliance. Despite these

This work was presented in abstract form at the Dysphagia Re-search Society meeting, Burlington, Vermont, 1999Correspondence to: David4 Thompson, M.D., Department of GISciences, University of Manchester, Hope Hospital, Salford M68HD, United Kingdom. Telephone: +44-161-737-4363. Fax: +44-161-737-4364; E-mail: dthompso@fs1.ho.man.ac.uk

Dysphagia 19:28–35 (2004)DOI: 10.1007/s00455-003-0032-8

‘‘treatments,’’ patients still continue to develop com-plications. In fact, poor compliance in dysphagic pa-tients is known to be associated with adverseoutcomes, including increased mortalities commonlycaused by aspiration pneumonia [9].

Although it has been suspected that somedysphagic patients are unaware of or underestimatetheir swallowing dysfunction [10,11], rather surpris-ingly this has never been systematically investigated.Moreover, this is particularly relevant after stroke,where patients frequently have impaired awareness ofeven the most debilitating motor, sensory, and cog-nitive dysfunction [12], a syndrome first described byBabinski in 1914 [13] and associated with frontal [14]and/or right parietal lesions [12]. Thus, one expla-nation for the variability in patient swallowing per-formance may be that dysphagic stroke patients havevariable levels of awareness of their swallowingproblems. This may partly explain why some dys-phagic patients are able to alter their eating behavior[15], presumably in an attempt to minimize thecomplications of dysphagia, such as aspiration. Therelationships between a patient’s perception of aswallowing problem, compliance with ‘‘treatment,’’and ability to make alterations on drinking is, how-ever, unclear.

The aim of this study was to determine theprevalence of impaired awareness of dysphagia afterstroke and how this affects swallowing perform-ance and clinical outcome. Since it seemed plausiblethat awareness of dysphagic symptoms might influ-ence a patient’s ability to perceive a ‘‘swallowingproblem,’’ we postulated that dysphagic patients whowere ‘‘aware’’ of their swallowing difficulties wouldboth drink differently and have more favorable clin-ical outcome when compared with those who hadpoor awareness of their dysphagia. A secondary hy-pothesis was that dysphagic patients with goodawareness of their dysphagic symptoms would bemore likely to admit that they had a ‘‘swallowingproblem.’’

Materials and Methods

Subjects

In this prospective study, all stroke patients admitted to hospital

over a consecutive three-month period (80 patients) were consid-

ered for inclusion. Patients were assessed within 72 h post stroke,

the diagnosis of hemispheric stroke being identified by clinical as-

sessment and confirmed by noncontrast computerized tomography

(CT) scan. Of the 80 stroke patients screened, 70 met the inclusion

criteria of being able to give informed consent, having a normal

consciousness level, having been free of dysphagia prior to

admission established using questions based on a Self-report

Symptom Inventory [16], and being able to conduct a satisfac-

tory dysphagia assessment. The study protocol was presented to

and approved by the Salford and Trafford Research Ethics

Committee.

Stroke Disability

The modified Barthel Index [17] was used to assess the severity of

disability following a stroke. The lowest score on the Barthel is 0

which indicates complete dependence on others and the highest

score is 100 which indicates independence.

Swallowing Assessment

A professionally qualified speech and language therapist clinically

assessed all patients using the standard hospital protocol of 3

teaspoons of water, followed by sips then cup drinking (30 ml). The

therapist used the Logemann clinical indicators [18] of dysphagia,

i.e., coughing, oral residue, delayed swallow, and reduced laryngeal

elevation (observed by placing one finger on the hyoid and one on

the thyroid [19]), throat clearing, and choking. The speech and

language/therapist classified patients as dysphagic or not using

these clinical indicators.

An objective assessment of swallowing behavior was then

carried out by the researcher independent of the clinical bedside

examination using a timed test [20]. The patient was presented with

50 ml of tap water in a beaker and asked to drink it ‘‘as quickly as

is comfortably possible.’’ The number of swallows was counted

during the total time taken from the onset (when the water touched

the patient’s lips) to the end of water consumption [20]. The av-

erage volume taken per swallow and the time taken to drink the

given volume were then calculated. If the patient did not drink the

whole amount, the residual volume was noted. It was noted if the

procedure was terminated by the researcher due to excessive

coughing on drinking.

Awareness Assessment

Awareness of swallowing dysfunction was identified using 8 ques-

tions (Appendix 1) to identify the patient’s own observation of the

clinical signs of aspiration. These questions were presented verbally

to the patients, immediately after the timed test. Patients were as-

sessed for receptive and expressive dysphasia and ability to give

100% reliable yes/no responses to a series of neutral questions

before they were able to participate in assessment of awareness.

There is no established reliable or valid assessment of awareness of

swallowing or any other motor impairment post stroke. In this

study assessment of awareness was made by the presence or ab-

sence of specific behaviors that did or did not occur on drinking.

The questions used to determine awareness were presented to each

patient in the same way and the assessor made no comments about

the patient’s swallowing during the assessment. The agreement

between the researcher and the patient with respect to the presence

or absence of clinical indicators of dysphagia was analyzed fol-

lowing the assessment (Appendix 2). If there was no agreement or

agreement with less than 50% of indicators (when more than one

indicator of dysphagia was observed by the researcher), the patient

was rated as having poor awareness. If there was full agreement or

agreement with greater than 50% of indicators (when more than

one indicator was observed by the researcher), the patient was rated

as having good awareness.

C. Parker et al.: Dysphagia Following Stroke and Swallowing Performance 29

Patient Perception of ‘‘a Swallowing Problem’’

After completing the above assessment, patients were then asked

the question that is commonly posed by health professionals in

clinical settings: Do you have a swallowing problem? Patients were

asked to respond only with a yes or no.

Patient Outcome at Three Months

The nondysphagic and dysphagic patients’ medical records were

accessed at three months to investigate the occurrence of pneu-

monia and death.

Data Analysis

The Mann–Whitney U test for nonparametric data was used for

comparison of the two groups. The values are expressed as the

median and interquartile range as data were not parametric.

Results

Patient data are shown in Table 1.

Barthel Indices

The scores for the Barthel indices of all the strokepatients indicate that there are differences betweenthe groups, with those with good awareness showinga lower median (20) than the group with poorawareness (48) and the nondysphagic group (78)(Table 1).

Clinical Swallowing Assessment and Awareness

Twenty-seven patients were identified by the asses-sor as dysphagic. Sixteen of the 27 dysphagic pa-tients demonstrated poor awareness of theirdysphagic symptoms (Appendix 2). The occurrenceof clinical indicators observed in those with goodand poor awareness of their dysphagia is shown inFigure 1.

Dysphagia Awareness and Swallowing Performance

Using the timed test (Fig. 2), the group with goodawareness drank more slowly (<1 ml/s vs. 5 ml/s,p = 0.03) and took a smaller average volume perswallow (6 ml vs. 10 ml, p = 0.04) than those withpoor awareness and those who were not dysphagic.By contrast, patients with poor awareness drank at asimilar speed (5 ml/s vs. 6 ml/s) and took similarvolumes per swallow (10 ml vs. 12 ml) compared withthe nondysphagic patients and there was no statisticaldifference between these two groups. Furthermore,compared with published data [20], the nondysphagic

group and patients with poor awareness did drinkmore slowly than healthy age-matched controls foramount taken per second [5 ml/s, 6 ml/s vs. 7.5 ml/s(women) and 14.6 ml/s (men)]. The nondysphagicgroup and patients with poor awareness also tooksmaller volumes than the published data for healthycontrols [10 ml, 12 ml vs. 10.6 ml (women) and 20 ml(men)]. Of the 16 dysphagic patients with poorawareness, 2 patients had to be stopped from drink-ing because of severe coughing and the remainderdrank the full volume offered. Only one of the 11dysphagic patients with good awareness drank all thewater offered.

Patient Perception of ‘‘a Swallowing Problem’’

Only 3 of the 27 dysphagic patients responded thatthey had a swallowing problem. One of these wasfrom the 16 patients with poor awareness of theirdysphagic symptoms and 2 were from the 11 pa-tients with good awareness of their dysphagicsymptoms.

Three-Month Outcome

A total of 9 dysphagic patients had died at 3 monthscompared to 3 nondysphagic patients (Table 1). Threeof the 9 dysphagic patients were considered to havegood awareness and six were considered to have poorawareness of their swallowing problems. None of the

Table 1. Demographic data

Dysphagic Nondysphagic

Poor

awareness

Good

awareness

No. of patients 16 11 43

Age (median, IQR)a 71.5

(67, 78.5)

66

(60, 76)

69

(64, 75.5)

Sex (male/female) 12/4 7/4 23/20

Hemispheric location

of stroke:

Left 1 3 14

Right 7 2 8

Bilateral 8 6 5

No lesion shown 0 0 16

Barthel Index

(median, IQR)a48

(4, 67)

20

(13, 58)

78

(6, 100)

3-Month outcome:

Pneumonia 5 0 1

Death 6 3 3

aIQR = interquartile range.

30 C. Parker et al.: Dysphagia Following Stroke and Swallowing Performance

patients with good awareness of their swallowing andone nondysphagic patient had pneumonia during thethree months, whereas five patients considered to havepoor awareness of their swallowing experiencedpneumonia during the three months.

Discussion

Our study has shown that over half of the dysphagicstroke patients studied had poor awareness of theirswallowing dysfunction and made no attempt tomodify their swallowing. However, regardless ofawareness of symptoms exhibited during the timedwater swallow test, they were still unable to identifythat they had a swallowing problem when asked thestandard clinical question: Do you have a swallowingproblem? Furthermore, we also found evidence tosuggest that poor awareness may result in worseoutcome at three months. These findings raise anumber of important questions that require discus-sion.

Two major questions arise from the results;First, how do those patients who are aware of theirdysphagia manage to make modifications to swal-lowing? Second, could these changes to volume and

speed on swallowing have any bearing on patientoutcome?

To address this first question, it is first im-portant to consider how awareness could affect theswallowing process. Both voluntary and reflexivecomponents are integrated in the oral phase inpreparation for swallowing [21]. In particular, itseems that the patient needs a voluntary motor planbefore actually swallowing, presumably to sampleand adjust the volume and speed of the oral contentsto be ingested. This may be influenced in part by thepatient’s appreciation of the difficulties he/she expe-riences when trying to drink, such as coughing.Patients with good awareness of their dysphagiaappear to be more sensitive to clinical indicators thatoccur on drinking, implying a greater level of antici-pation on swallowing. One reason for this sensitivitymay relate to how the swallowing cortical network isorganized. For example, there is evidence to suggest

Fig. 1. The clinical indicators that occurred on assessment of

swallowing in patients with good and poor awareness of their

dysphagia. The clinical indicators observed were coughing, throat

clearing, changes to voice quality, time taken to swallow, and

excessive saliva.

Fig. 2. Box plots of the average volume per swallow and average

amount taken per second. The shaded area represents the interquartile

range of the results for nondysphagic stroke patients. The black box

represents the dysphagic patients with poor awareness, and the white

box represents the dysphagic patients with good awareness. The

dividing lines in each box represent the median amount taken, with

the top and bottom of the boxes representing the upper and lower

quartile ranges.

C. Parker et al.: Dysphagia Following Stroke and Swallowing Performance 31

that cortical (and subcortical) control [22,23] is in-volved in the preparation and planning of taskswhich would be accessed prior to swallowing. Thismay be important in the ability of the patients tojudge that there needs to be a change in the way theydrink. Thus, it has been suggested that ability to planat a cortical level may influence whether those dys-phagic patients who are aware of their symptoms ofdysphagia could make behavioral modifications priorto each swallow by ingesting smaller volumes andtaking more time to drink. In contrast, it may be thatpatients, regardless of awareness of their dysphagia,lack this ‘‘judgment’’ ability and ingest as large avolume of water as quickly as nondysphagic strokepatients. Linking patient awareness of symptoms toan ability to preplan is, at present, purely speculation.Further work would be needed to establish if im-pairment of the frontal cortex, which has been linkedwith planning, occurs in patients with good and poorawareness and if this is connected in any way to pa-tient awareness of dysphagic symptoms and ability tomake modifications to drinking.

Patient awareness and the effect that it mayhave on the preparation stage of swallowing may alsoimpact the patient’s ability to modify the respiratorypattern around a swallow. The swallowing–breathinginteraction, which normally results in a momentaryapnea followed by expiration, is considered an addi-tional protection for the airway. Dysphagic patientscommonly display abnormal patterns of respirationon swallowing which can result in inspiration afterswallowing. It would be interesting to examinewhether patients displayed different patterns of res-piration on swallowing in relation to their ability tomake modifications to drinking and how aware theyare of their swallowing problems.

Next we address the second question arisingfrom this study’s findings: Does the ability to drinksmaller volumes more slowly reduce aspiration andhave a bearing on dysphagic stroke patient out-come? The only evidence using comparable volumesrelates to healthy adults of all age ranges, includingthe elderly. Nilsson [24] found that elderly patientstook different volume sizes on drinking. Those thattook large volumes were found to have greatly in-creased laryngeal and pharyngeal movements. Thiswas supported by a study [25] that looked at healthyadults taking large-volume swallows and found therewere extensive changes in the pharynx on swallow-ing that did not occur on smaller-volume swallows.The research on healthy adults [26] indicates thatlarge bolus volumes do result in ‘‘substantial phys-iological modifications’’ on swallowing. The impli-cations for the dysphagic stroke patient are that

larger volumes generally place greater demands onthe oropharyngeal phase of swallowing. Therefore,those with poor awareness of dysphagia are proba-bly placing a greater demand [27] on an alreadydysfunctional swallowing process, which may in-crease the chance of aspiration and poorer clinicaloutcome. In fact, speech and language therapistsfrequently recommend small volumes with the pre-mise that ‘‘If a patient is at risk of aspiration, he orshe may aspirate more on a larger bolus. It is im-portant to place the patient at minimal risk for as-piration by providing him or her with a smallamount of material’’ [19]. The outcome data in thisstudy do appear to support this contention as therewere more complications and death associated withpatients who appeared to have poor awareness oftheir dysphagia and did not, or were unable to,make modifications to drinking. However, thenumber of patients with complications followed upat three months was small, and in the absence of alarger clinical trial, these observations must remainopen. The impact of awareness on patient outcomeclearly needs further investigation, as well as lookingat the impact of patient compliance, ability to makemodifications on drinking, specific lesion location,and stroke severity.

It is of interest to note that severity of disa-bility of stroke patients in this study (at least asmeasured by the Barthel Index), showed that dys-phagic patients with good awareness had a lowerscore, meaning greater dependence on others, thanthe dysphagic patients with poor awareness and thenondysphagic stroke group. This could indicate thatseverity of disability may not affect patient awarenessof swallowing problems or their ability to makemodifications to drinking. It is more likely that se-verity of stroke and precise lesion location, whichwere not examined, may be a more useful indicator ofimpaired awareness of dysphagia and should beidentified in future work. In particular, it would beuseful to carry out a blinded evaluation of the lesionsite, especially involvement of the basal ganglia andsubcortical structures versus awareness and dyspha-gia severity. Indeed, in one study the severity ofdysphagia post stroke appeared more closely relatedto the representation of swallow function in the un-affected hemisphere [28], implying independence fromstroke severity.

Because of the small sample size in this study,no statistical comparisons could be made between thegroups in terms of affected hemisphere. However, itdid appear that there was a trend towards poorawareness being associated with bilateral and right-sided lesions. This would support existing evidence

32 C. Parker et al.: Dysphagia Following Stroke and Swallowing Performance

[12] that suggests impaired awareness may occur be-cause of lesions on the right side in the parietal re-gion. However, some of the patients with goodawareness were also found to have bilateral andright-sided lesions. The limited information availablefor these patients relating to the extent and exactlocation of the lesion makes it difficult to speculate onthe results found, but it seems plausible that aware-ness would be dependent on the exact location of thelesion. These findings may also highlight the diffi-culties involved in attempting to assess awareness ofdysphagia and the lack of sensitivity of the tool used,which may not have identified impaired awareness inall of the dysphagic patients who may have had poorawareness.

Our study has also established that dysphagicpatient awareness of clinical indicators is surpris-ingly low. Moreover, the majority of dysphagicstroke patients, regardless of whether they havegood or poor awareness of dysphagia, are unlikely toacknowledge that they have a swallowing problem.The results suggest that the question ‘‘Do you have aswallowing problem?’’ has little relevance to thedysphagic patient even if he/she has an awareness ofhis/her dysphagia. This clearly has many implicationsfor those health professionals involved in patient as-sessment post stroke and indicates that the questionhas low validity in clinical use. It is not knownwhether patients with impaired awareness are lesslikely to comply with treatment modifications orwhether increased education and explanation re-garding dysphagia will help them to have increasedawareness of their own difficulties. It would be in-

teresting to examine whether awareness of dysphagiachanges over time and the impact this has on com-pliance and the ability to make modifications todrinking.

In conclusion, we have shown that some dys-phagic stroke patients, who appear to have goodawareness of their dysphagia, are able to alter theirswallowing performance by drinking small volumesslowly, which is likely to place less demand on theoropharynx. This appears to result in improved out-come for a small number of patients but furtherinvestigation is needed to investigate whetherawareness, compliance, or ability to exercise judg-ment in monitoring drinking has an impact on patientoutcome. Dysphagic stroke patients in this studywere found to frequently have difficulty in identifyingtheir symptoms of dysphagia and rarely identifiedthat they had swallowing problem, which suggeststhat clinicians should not rely purely on patient self-assessment of dysphagia as patient and professionalperceptions differ greatly. A larger study is now re-quired to define more precisely the clinical relevanceand the implications of these findings for routinepractice.

Acknowledgments. This study was supported by a grant from the

North Western Regional Health Authority Biomedical Research

Fund. We would also like to thank the Speech and Language

Therapy Department of Hope Hospital for supporting this study

and Elizabeth Hill for statistical advice. Shaheen Hamdy is an

MRC (UK) Clinician Scientist. Maxine Power was an MRC (UK)

Clinical Training Fellow. The Stroke Association funded Audrey

Bowen and Pippa Tyrrell.

Appendix 1: Swallowing Questionnaire

The detailed question based assessment used on all dysphagic patients following clinical assessment of swal-lowing to determine which patients had good or poor awareness of their swallowing problems.

Therapist PatientYes No Yes No

1. Did you have difficulty keeping drink in your mouth?2. Did you cough when you were drinking?3. Did you cough after drinking?4. Did it take a long time to drink?5. Did you get short of breath when drinking?6. Did you clear your throat after a drink?7. Did your voice sound different after a drink?8. Did you produce a lot of saliva?

C. Parker et al.: Dysphagia Following Stroke and Swallowing Performance 33

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Appendix 2

Raw data of patient and researcher responses to questions (Appendix 1) to assess awareness of dysphagic symptoms.

Patient Q1 Q2 Q3 Q4 Q5 Q6 Q7 Q8

1. N/N N/N Y/Y Y/Y N/N N/N N/N Y/Y2. N/N Y/Y Y/Y N/Y N/N N/N Y/Y Y/Y3. N/N Y/Y Y/Y Y/Y Y/Y N/N N/N N/N4. N/N N/N Y/Y Y/Y N/N N/N N/N Y/Y5. N/N N/N Y/Y N/N N/N N/N Y/Y Y/Y6. N/N N/N Y/Y Y/Y N/N N/N Y/Y Y/Y7. N/N Y/Y Y/Y Y/Y N/N N/N N/N N/N8. N/N N/N Y/Y N/N N/N N/N Y/Y Y/Y9. N/N N/N Y/Y N/N Y/Y N/N Y/Y Y/Y10. N/N Y/Y Y/Y N/N N/N N/N N/N Y/Y11. N/N N/N Y/Y Y/Y N/N N/N N/N N/N12. N/N N/Y N/Y N/Y N/N N/N N/Y N/N13. N/N N/N N/Y N/Y N/N N/N N/N N/N14. N/Y N/N N/Y N/Y N/Y N/N Y/Y N/N15. Y/Y N/N N/Y N/Y N/Y N/N N/Y N/N16. N/N N/Y N/Y Y/Y N/N N/N N/Y N/N17. N/Y N/N N/Y N/N N/N N/N N/Y N/Y18. N/N N/N N/Y N/Y Y/Y N/N N/N N/N19. N/N N/N Y/Y N/N N/Y N/Y N/Y N/N20. N/N N/N N/Y N/N N/Y N/N N/Y N/N21. N/Y N/N Y/Y N/Y N/N N/N N/Y N/N22. N/N N/N N/Y N/Y N/N N/Y N/N N/N23. N/N N/N N/Y N/Y N/N N/N N/Y N/N24. N/N N/N N/Y N/Y N/Y N/N N/Y N/N25. N/N N/Y N/Y N/Y N/N N/N N/N N/Y26. N/N N/N N/Y N/N N/N N/N N/Y N/N27. N/N N/N N/Y N/N N/Y N/Y N/Y N/N

Note: N = No response, Y = Yes response; order = Patient/Researcher.

Nonagreement between patient and researcher highlighted.

Patients 1–11 = good awareness, patients 12–27 = poor awareness.

34 C. Parker et al.: Dysphagia Following Stroke and Swallowing Performance

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C. Parker et al.: Dysphagia Following Stroke and Swallowing Performance 35