The feasibility and test–retest reliability of the Dutch Swal-Qol adapted interview version for dysphagic patients with communicative and/or cognitive problems

Article (PDF Available)inQuality of Life Research 22(4) · May 2012with42 Reads
DOI: 10.1007/s11136-012-0202-y · Source: PubMed
Abstract
Purpose The adaptation of the Dutch Swal-Qol questionnaire to an interview format suitable for dysphagic patients with communicative and/or cognitive problems and evaluation of the feasibility and test–retest reliability. Methods An observational study with two measurements within a 2-week time period in a sample of 57 stroke patients with dysphagia in a nursing home environment. The interview version of the Swal-Qol was evaluated in the total group and in subgroups of patients with and without communicative and/or cognitive problems. Results The constructed interview version was considered feasible from an expert’s and patient’s point of view. The overall score and seven subscales of the Swal-Qol showed an excellent test–retest reliability (k > 0.75), and two subscales were considered good (k > 0.60). Conclusions This study showed that using a structured, and at the same time flexible, interview format tailored to the individual needs of stroke patients enhances the feasibility and does not compromise the test–retest reliability.

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BRIEF COMMUNICATION
The feasibility and test–retest reliability of the Dutch Swal-Qol
adapted interview version for dysphagic patients
with communicative and/or cognitive problems
Jessie Lemmens
Gerrie J. J. W. Bours
Martien Limburg
Anna J. H. M. Beurskens
Accepted: 11 May 2012 / Published online: 30 May 2012
Ó The Author(s) 2012. This article is published with open access at Springerlink.com
Abstract
Purpose The adaptation of the Dutch Swal-Qol ques-
tionnaire to an interview format suitable for dysphagic
patients with communicative and/or cognitive problems
and evaluation of the feasibility and test–retest reliability.
Methods An observational study with two measurements
within a 2-week time period in a sample of 57 stroke
patients with dysphagia in a nursing home environment.
The interview version of the Swal-Qol was evaluated in the
total group and in subgroups of patients with and without
communicative and/or cognitive problems.
Results The constructed interview version was consid-
ered feasible from an expert’s and patient’s point of view.
The overall score and seven subscales of the Swal-Qol
showed an excellent test–retest reliability (k [ 0.75), and
two subscales were considered good (k [ 0.60).
Conclusions This study showed that using a structured,
and at the same time flexible, interview format tailored to
the individual needs of stroke patients enhances the feasi-
bility and does not compromise the test–retest reliability.
Keywords Test–retest reliability Feasibility
Dysphagia Quality of life Swal-Qol
Introduction
Health Related Quality of Life (HRQOL) scales are
patient-reported outcome measures for gaining information
about a patient’s own health situation [1, 2]. When
assessing patients with communicative and/or cognitive
problems, caution is needed when using traditional
HRQOL scales since difficulties in understanding or
answering may occur [35]. Several studies give recom-
mendations for adjustments for patient groups with com-
municative and cognitive problems [69]. McHorney et al.
[10] developed the Swal-Qol questionnaire to evaluate the
impact of dysphagia on quality of life and was shown to be
a reliable and valid tool for measuring quality of life in
outpatients [1114]. However, the current self-report ver-
sion is not feasible for patients as half of them need
assistance in filling it out [11, 13, 15]. Therefore, the aim of
this study was to adapt the Swal-Qol questionnaire for
dysphagic stroke patients with and without communicative
and/or cognitive problems and evaluate its feasibility and
test–retest reliability.
Methods
Design
A cross-sectional, clinimetric study design was used
with two measurements in a 2-week time period in a
sample of dysphagic stroke patients in a nursing home
environment.
Materials and methods
The Swal-Qol consists of 44 items divided in 10 scales
regarding quality of life: (1) burden, (2) eating duration,
(3) eating desire, (4) food selection, (5) communication,
(6) fear, (7) mental health, (8) social functioning, (9)
fatigue and (10) sleep that could be rated on a 5-point
J. Lemmens (&) G. J. J. W. Bours M. Limburg
A. J. H. M. Beurskens
Zuyd University of Applied Sciences, Heerlen, The Netherlands
e-mail: je.lemmens@hszuyd.nl
123
Qual Life Res (2013) 22:891–895
DOI 10.1007/s11136-012-0202-y
Likert scale. In addition, there are scales on symptom
frequency, nutrition intake (tube, consistency of food
and/or liquids), assistance with filling out, general health
and some demographics [14]. We adapted the Dutch
translation of the Swal-Qol [15] into an interview version
by using a two-step response method with supportive
visual aids [69]. The adaptation process is described in
Box 1.
Participants
Stroke patients with dysphagia were recruited by speech
and language therapists (SLTs) responsible for dysphagia
treatment in nursing homes. Patients were eligible when
they were physically and mentally fit enough to participate.
Patients were excluded if they did not speak Dutch. The
SLTs gave eligible patients oral and written information
Box 1 Swal-Qol adaptations, from self-report to interview version
Purpose: enabling patients to portray their own perspective, instead of depending on proxy reports[3].
Step 1: developing a standardized interview format
The interviews format was adjusted to the communicative capabilities of the patients by:
- using questions instead of statements [4-8],
- administrating scales and items in a flexible order,
- giving explanations or demonstrations of unclear items such as ‘clearing throat’ [9].
Purpose: limiting item sampling errors.
Step 2: simplifying instructions and items
The comprehension of items was enhanced by:
- using directive speech [6],
- rephrasing items in which vague language or negative phrasing was used [14],
- changing the recall time from ‘last month’ to ‘last week’ [8].
Purpose: designing a suitable ordinal scale for patients for whom Likert scales are problematic [8, 18], by:
Step 3: revising the five-point Likert scale
- creating a two step responds method (see example).
Purpose: supporting verbal communication which benefits comprehension, focus and memory.
Step 4: designing visual aids
Different layout styles were designed:
- a) enlarged font, b) key words in bold/underlined, c) separate pages for each item,
d) separate response cards,
- vertical response cards for patients with a neglect or hemianopia [10].
Purpose: combining theoretical and practical insight and getting independent approval for practical use.
Step 5: involvement of experts
Five independent SLT’s with at least three years of experience with dysphagic stroke participated by:
- giving suggestions for tailoring the original Swal-Qol,
- confirming the suitability of the adapted interview, instructions, items and response scales.
Example:
Interviewer asks : ‘Is it difficult to deal with your swallowing problem?
Patient answers: ‘yes’, ‘no’ or comes up with a more specific answer for example: ‘depends on the day’ or ‘I
don’t know’.
If yes: the interviewer nods and responds (in neutral tone while observing the patients reaction): ‘ah, it is’. Then
asks a second question: ‘Is it very difficult (1), remotely difficult (2) or a little bit difficult (3) for you?’
If no: the interviewer shakes his head and responds (in neutral tone while observing the patients reaction): ‘ah, it
is no problem for you’. Then asks a second question: ‘Is it never a problem (5) for you or occasionally (4)?’
In case a patient doesn’t know, the interviewer checks if the patient doesn’t recall or if the item is unclear and
then gives a suitable explanation.
If necessary the interviewer repeats every answer option separately or suggests to use a visual aid.
Dealing with my Swallowing Problem is very
Very True Partly True A Little true Almost never true Not true at all
difficult
1 2 3 4 5
892 Qual Life Res (2013) 22:891–895
123
and asked permission for the interviewers to approach
them. If patients were not able to give written consent,
permission was asked in the presence of family members.
If at 2-week follow-up patients did not recall giving con-
sent, it was asked for again.
Measurements
Patient characteristics
Communicative problems as dysarthria and aphasia were
diagnosed by a SLT. Cognitive problems were defined as
neuropsychological symptoms following stroke and were
diagnosed by a psychologist. The severity of dysphagia
was determined by feeding status. Dysphagia was consid-
ered ‘severe’ when patients were fed by tube (with and
without oral intake), ‘moderate’ when there was oral intake
with adjusted consistency and ‘mild’ in the case of normal
oral intake with adaptive strategies.
Feasibility
Feasibility was defined as time to complete the interview,
use of visual aids, item comprehension and burden from an
observer’s and patient’s perspective. Burden was described
as to what extent the interview had been tiresome for the
patient. Regarding the patient’s perspective, two questions
on a three-point scale about comprehension and burden
were asked.
Test–retest reliability
Test–retest reliability was assessed by administrating two
identical Swal-Qol interviews with the same interviewer.
A 2-week time interval was considered enough time for
patients not to remember their previous answers.
Procedures
The SLTs and psychologist diagnosis were derived from
the patients’ medical records to gather information on
communication and cognition. Two trained assessors, one
interviewer and one observer, conducted all the interviews.
All patients were asked whether they preferred to use
visual aids. The interviewer administered the Swal-Qol
interview and wrote down the answers given by the patient;
the observer reported the feasibility aspects. The use of
visual aids and explanations were standardized in the
second interview to guarantee that both interviews were
identical. Before the second interview, the assessors
checked whether no major changes had occurred in health
status.
Data analyses
The Predictive Analytics Software (PASW, version 18)
program was used for data analyses. Patient characteristics
were reported in frequencies. Subgroups were formed based
on the presence of communicative and/or cognitive prob-
lems. Feasibility aspects were analyzed using descriptive
techniques (i.e., mean, standard deviation, frequencies).
Subscales with at least one incomplete answer were
excluded from test–retest analyses. The test–retest reli-
ability for each subscale and overall score was reported by
the weighted kappa and is considered good between 0.40
and 0.75 and excellent above 0.75 [16, 17]. To compare the
data with previous published studies, the Spearman’s rho
correlation coefficients and the intraclass correlation coef-
ficients (ICC) were calculated.
Results
Participants
A total of 61 patients met the inclusion criteria of whom 57
gave their consent and 56 participated in both interviews.
Data were collected from April 2008–December 2009 in
seven nursing homes in the Netherlands. The average age
was 75.1 (±SD 12.1). Communication problems were
present in 30 (53 %) patients. The most frequent diagnosis
was aphasia or dysarthria (n = 24). Three patients had both
speech and language problems. Cognitive problems
occurred in 12 (21 %) patients and existed mostly of
amnesia or neglect (n = 11; Table 1). Two patients had
cognitive as well as communicative problems of whom one
only participated in the feasibility study.
Feasibility
The average time to complete the interviews was 41 (±SD
28) min, and 29 (37 %) patients needed 30 min or more.
There were no major differences between the group with
and without communicative and/or cognitive problems.
Visual aids were used in 30 (53 %) interviews. Half of
the patients without communicative or cognitive problems
(n = 8) preferred visual aids. Only the enlarged font
questionnaire (n = 11: 19 %) and separate response cards
(n = 18: 32 %) were applied, mainly to help patients
sustain attention.
Difficulties in comprehension were reported in all 44
items of the Swal-Qol. In 12 (21 %) interviews, a pause
was needed, prolonging the administration time. Item
comprehension was easy to 45 (78 %) patients and difficult
to three (5 %) patients. The majority of the patients (82 %)
found the burden acceptable to low.
Qual Life Res (2013) 22:891–895 893
123
Test–retest reliability
The average time between the two interviews was 14.9 (±
SD 3.1) days with a minimum of 7 and maximum of 24
(range = 17) days. Due to missing data, the sample size
per subscale varied between 48 and 56 patients (Table 2).
The weighted kappa was excellent (k [ 0.75) for the
overall score and seven subscales of the total group
(n = 56), the group with (n = 40) and without communi-
cative and/or cognitive problems (n = 16). It was good for
subscale ‘fear’ (k = 0.675/0.677/0.660) and ‘fatigue’
(k = 0.713/0.736/0.631). A further comparison between
communicative and cognitive problems showed that all
scales were excellent for the group with communicative
problems (n = 30). The sample size of the cognitive
impaired group was considered too small for analysis.
There were no major differences in test–retest reliability
between the use of the weighted kappa, the Spearman’s rho
and ICC (Table 2).
Discussion
This study showed that using a structured, and at the same
time, flexible interview format tailored to the individual
needs of patients enhances the feasibility and does not
compromise the reliability for dysphagic stroke patients
with problems in communication and cognition.
In general, an interview format is more time-consuming
and requires more resources and training, but we demon-
strated that our adaptations led to a scale applicable within
Table 1 Sample characteristics (n = 57)
n (%)
Gender
Male 24 (42)
Age
Mean (SD) 75.1 (12.1)
Min 46
Max 94
Highest completed education
Elementary school 22 (39)
High school 16 (28)
Vocational training 14 (25)
University 5 (9)
Dysphagia
Severe: tube feeding 9 (16)
Moderate: oral intake with adjusted consistency 25 (47)
Mild: normal oral intake with adaptive strategies 21 (37)
Communication and/or cognitive problems
a
41 (72)
Communication problems
a
33 (58)
Aphasia (language) 12 (21)
Dysarthria (speech/voice) 12 (21)
Buccofacial/verbal apraxia (speech) 5 (9)
Unclassified diagnosis (speech/language) 4 (7)
Cognitive problems (neuropsychological symptoms)
a
12 (21)
Amnesia 6 (11)
Neglect/hemianopia 6 (11)
None 16 (28)
a
Patients can experience several problems in communication and/or
cognition
Table 2 Test–retest reliability
of the Swal-Qol subscales
(n = 56)
a
n is smaller than the group
size given at the top of each
subgroup
Subscale (# items) n Total
group
(weighed
kappa)
Total group
(Spearman’s
rho/
ICC)
Subgroups (weighed kappa)
Problems with
communication
and/or cognition
(n = 40)
No problems
with
communication/
cognition
(n = 16)
1 Burden (2) 56 0.849 0.854/0.850 0.862 0.815
2 Eating duration and desire
(5)
54 0.822 0.828/0.817 0.811
a
0.856
3 Dysphagia symptoms
(14)
54 0.940 0.934/0.941 0.960
a
0.779
4 Food selection (2) 53 0.823 0.834/0.818 0.836
a
0.804
a
5 Communication (2) 56 0.786 0.777/0.789 0.790 0.761
6 Fear (4) 53 0.675 0.715/0.678 0.677
a
0.660
a
7 Mental health (5) 55 0.898 0.877/0.891 0.879 0.946
a
8 Social functioning (5) 48 0.908 0.909/0.909 0.931
a
0.785
a
9 Fatigue and sleep (5) 55 0.713 0.710/0.714 0.736 0.631
a
Overall score (44) 48 0.953 0.951/0.952 0.960
a
0.924
a
894 Qual Life Res (2013) 22:891–895
123
30 min in half of the cases. In comparison with previous
Swal-Qol studies, with an average fill-out time between 14
and 30 min [11, 13, 15], time to complete our interviews
was much longer, mostly due to storytelling. However, the
length of the Swal-Qol interview is considered feasible,
since the majority of patients did not experience a heavy
burden and were satisfied with the time to complete and the
attention given by the interviewer.
Caution is needed when comparing our test–retest reli-
ability results with previous studies, since these studies
used the self-report version and excluded patients with
communicative and cognitive problems. Their population
was not limited to stroke, the sample sizes were small
(n \ 40), and most patients were not living in nursing
homes. Despite these differences, the results of our test–
retest reliability analysis are largely comparable with pre-
vious studies.
The absence of recent objective test results to estimate
the communicative and/or cognitive problems might have
influenced the group composition for the subgroup analy-
sis. Since our population consisted of a group of very frail
elderly, it was not considered ethical or practical to use
additional standardized tests; instead, the diagnosis was
derived from medical records. As group comparisons
showed no major differences between feasibility aspects
and test–retest reliability, it is not likely that this had a
large impact. Moreover, by allowing a group of patients to
participate who are usually excluded from research, we
believe our data are based upon a more representative
group of dysphagic stroke patients than reported thus far.
By tailoring measurement instruments for specific
patient groups without compromising the clinimetric
properties, data on subjective health status can be collected
in a larger and more representative population, which
benefits both research and clinical purposes. We think that
more specific instruments in different domains can be
adapted for use in this specific group of patients.
Acknowledgments The authors would like to thank all the patients,
SLTs and nursing homes for their participation. We acknowledge our
assessors and especially L.H.J. Smeets for her contribution to this
study.
Open Access This article is distributed under the terms of the
Creative Commons Attribution License which permits any use, dis-
tribution, and reproduction in any medium, provided the original
author(s) and the source are credited.
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