Abstract
Introduction: Dysphagia is a prevalent symptom of various neurological diseases and is associated with decreased quality of life. The M.D. Anderson Dysphagia Inventory (MDADI) is globally utilized tool to assess the impact of dysphagia on quality of life. However, a Turkish version of the scale is not yet available. This study aimed to translate, culturally adapt, and evaluate the validity and reliability of the Turkish version of the MDADI. Methods: One hundred twenty-four patients who were diagnosed with definite neurological disease completed the study. The cross-cultural adaptation and translation process of the MDADI adhered to the World Health Organization’s guidelines using the forward-backward translation method. The feasibility and the floor and ceiling effects were evaluated. Cronbach’s alpha was used to assess internal consistency. The Bland and Altman method and interclass correlation coefficient (ICC) were used to evaluate test-retest reliability. Absolute reliability was determined using the standard error of the measurement (SEM) and minimal detectable change (MDC). Construct validity was assessed using Pearson’s correlation coefficient between the MDADI and the Turkish Swallowing Quality of Life (T-SWAL-QOL) questionnaire. Results: Our study had a feasibility rate of 100%. No floor or ceiling effects were determined for any subscale or composite scores of the T-MDADI. The T-MDADI demonstrated excellent reliability, with Cronbach’s alpha coefficients ranging from 0.89 to 0.96 and ICC values from 0.81 to 0.95, confirming strong internal consistency and test-retest reliability. Measurement precision was supported by a SEM of 3.96 and an MDC of 10.97 for the composite score. In terms of validity, significant correlations were observed between T-MDADI subdomains and T-SWAL-QOL subdomains (r = 0.61–0.80 for food selection, mental health, and social functioning; r = 0.41–0.60 for eating duration and communication; p < 0.01), demonstrating good to very good convergent validity. Conclusion: The T-MDADI demonstrates validity and reliability as a questionnaire for assessing dysphagia-related quality of life in Turkish patients with neurological diseases.
Introduction
Swallowing is a fundamental and complex physiological process in humans. It involves a highly intricate neuromuscular process, necessitating exact bilateral coordination of over 25 pairs of muscles [1]. Additionally, the neural system encompassing the brainstem and cortical and subcortical areas plays a vital role in modulating swallowing [1, 2]. Hence, it is unsurprising that neurological diseases can significantly affect swallowing function.
Dysphagia is a hazardous symptom of many neurological diseases, occurring either acutely or chronically [3]. Stroke (ischemic or hemorrhagic) and/or traumatic brain injuries are the most well-known acute conditions that cause neurogenic dysphagia. Although dysphagia may appear acute, it can become chronic if recovery is not achieved. Studies indicate that approximately 60% of patients develop dysphagia after an ischemic stroke, with nearly 50% continuing to experience it 6 months after stroke [4, 5]. Dysphagia is also a predictable symptom of neurodegenerative diseases (Parkinson’s disease, amyotrophic lateral sclerosis, and multiple sclerosis), and the underlying mechanisms of dysphagia in neurodegenerative diseases are different from those in acute neurological conditions [6]. Symptoms are intricately linked to the nature of the disease, with many displaying a progressive course over time. Although the source of dysphagia differs among neurological diseases, clinical symptoms are serious and can lead to life-threatening conditions [3].
Swallowing is not only a physiological function in human life but also has significant psychological aspects. Dysphagia directly affects people’s eating functionality and indirectly affects their comfort zone, socialization, self-identity, happiness, anxiety, and so on [7]. These points are all interconnected with quality of life (QOL), and dysphagia can lead to decreased QOL in patients with neurological diseases [8]. In the literature, many QOL questionnaires related to dysphagia have been utilized in patients with neurological diseases [9‒12]. One of them is the M.D. Anderson Dysphagia Inventory (MDADI) [12]. This questionnaire was developed to determine the effects of dysphagia on the QoL of patients with head and neck cancer [12]. The MDADI has been successfully validated in the Japanese, Danish, Dutch, Swedish, Persian, Korean, Arabic, Spanish, French, Chinese, Italian, Portuguese, Indonesian, and Thai languages with high reliability [13‒26]. Although originally designed to assess QoL in patients with head and neck cancer, the Dutch and Swedish versions have been validated for use in patients with neurological diseases as well [15, 16].
The SWAL-QOL is the most commonly used dysphagia-specific QoL questionnaire for patients with neurological diseases [9]. This has also been validated in Turkish [27]. However, the SWAL-QOL questionnaire has 44 items compared to the MDADI (20 items) and thus takes a long time to complete, especially for patients with neurological diseases. Additionally, there is currently no validated dysphagia-specific QoL questionnaire in Turkish that is shorter and easier to complete for patients with neurological diseases. This study aimed to translate, cross-culturally adapt, and assess the validity and reliability of the Turkish version of the MDADI for utilization among patients with neurological diseases in Turkey.
Methods
Participants
This cross-sectional prospective study was conducted from February 2023 to April 2024. Patients with neurological diseases (n = 124) were recruited from the Department of Neurology of Suleyman Demirel University Hospital (Isparta, Turkey), Harran University Hospital (Sanliurfa, Turkey) and Department of Physiotherapy and Rehabilitation of Gazi University (Ankara, Turkey). The inclusion criteria were (1) willingness to enroll in the study, (2) diagnosed with a neurological disease and suffering from swallowing difficulty for at least 1 month, (3) age ≥18 years, (4) native Turkish speakers, and (5) ability to respond to a self-administered survey. The exclusion criteria were as follows: (1) illiterate, (2) Mini-Mental State Examination score of less than 24, (3) clinical instability, (4) history of head and neck cancer, and (5) acute medical illnesses (pharyngitis, pneumonia, etc.). The study required a sample size of 100 participants in accordance with Fayers and Machin’s guidelines [28], which suggest having 5–10 respondents per survey item. All the participants provided written informed consent. The study protocol was approved by the Ethics Committee of Gazi University (2023-1441) and registered at ClinicalTrials.gov (registration number: NCT06197451).
Cross-Cultural Adaptation and Translation Process
The cross-cultural adaptation of the MDADI followed established guidelines [29‒31]. Permission was obtained from Dr. Amy Y. Chen, the original author of the MDADI, to translate and adapt the scale into Turkish. Two native Turkish authors proficient in English independently translated the original MDADI into Turkish. The two translations were then compared and combined into a single consensus version, ensuring linguistic consistency and cultural appropriateness. The consensus Turkish version was back translated into English by two bilingual individuals who were unaware of the original MDADI. This step was undertaken to ensure the accuracy of the translation and to confirm that the meaning of the items was preserved. The back-translated version was reviewed and approved by Dr. Amy Y. Chen. An Expert Committee comprising a physiotherapist, neurologist, speech therapist, and laypersons evaluated the Turkish version for cultural relevance and face validity. The committee ensured that the items were clear, culturally appropriate, and relevant to Turkish patients. The finalized Turkish version was tested in a pilot study involving eight Turkish-speaking patients with neurological disorders. Participants provided feedback on the clarity and comprehensibility of the scale. All items were reported as clear and understandable, and no further modifications were necessary. The results from the pilot study were excluded from the final statistical analysis.
Data Collection
Participants completed the T-MDADI and T-SWAL-QOL through face-to-face interviews. Demographic data, including age, gender, and education level, were recorded. One week later, the T-MDADI was readministered to evaluate test-retest reliability.
Study Instrumentals
The MDADI
The MDADI is a self-administered questionnaire developed by Chen et al. [12] to determine the effects of dysphagia on QOL. This questionnaire comprises 20 items organized into four subscales. The global subscale includes only one item, the functional subscale includes 5, the emotional subscale 6, and the physical subscale includes 8 items. The scoring ranges from 1 (strongly agree) to 5 (strongly disagree) for all items, except E7 and F2. For them, the scoring was reversed, with 1 point reflecting “strongly disagree” and 5 points indicating “strongly agree.” The survey generated two summary scores: global and composite scores. The global score was derived from the first item, ranging from 1 (very low functioning) to 5 (very high functioning). The composite score was calculated by summing the emotional, physical, and functional subscale scores, dividing the total by 19 to compute the mean score, and then multiplying the mean score by 20 to obtain the final score. The composite score ranges from 20 to 100, with higher scores indicating better functioning [12].
The SWAL-QOL
The SWAL-QOL survey was created to assess dysphagia-related QOL [9]. It comprises 44 items that are organized into 11 subscales. The dysphagia-related QOL section included eight subscales: general burden, food selection, eating duration, eating desire, fear of eating, communication, social functioning, and mental health. The generic QOL section includes two subscales: fatigue and sleep. Lastly, the dysphagia clinical symptom section included only the symptom subscale. Some items addressed frequency, whereas others focused on agreement among items. The score of each subscale ranges from 0, indicating severe impairment, to 100, reflecting no impairment. Completing the survey typically takes 20–30 min. The survey was translated into Turkish and subsequently validated as the T-SWAL-QOL [27]. In this study, the T-MDADI was used as the index test, and the T-SWAL-QOL served as the reference test for evaluating construct validity.
Statistical Analysis
All statistical analyses were performed using the Statistical Package for the Social Sciences (SPSS) software for Microsoft version 25 (IBM Corp., Armonk, NY, USA). Data normality was assessed using the Shapiro-Wilk test. Statistical significance was set at p < 0.05 (two-tailed). Descriptive statistics were used to analyze the patients’ baseline characteristics. The means and standard deviations were used to determine the initial and retest completion of the T-MDADI.
Feasibility
Feasibility was evaluated based on the percentage of missing items (no answers for every item).
Floor and Ceiling Effects
Floor and ceiling effects were calculated by analyzing the proportion of patients who scored either the lowest or highest on the MDADI subscales and composite scores. Floor and ceiling effects were noted when over %15 of patients achieved either the lowest or the highest score [32].
Reliability
Reliability in this study was evaluated using internal consistency, test-retest reliability, and measurement errors. Internal consistency evaluates how well each item within a subdomain measures the same concept, specifically the emotional, functional, and physical subdomains [32]. Cronbach’s alpha was calculated to assess internal consistency reliability, with a coefficient of 0.70 deemed as the minimum acceptable threshold for conducting group-level comparisons [32]. Test-retest reliability was evaluated using the interclass correlation coefficient (ICC) and Bland-Altman method. ICC values of at least 0.70 were considered acceptable, values over 0.80 were considered good, and values over 0.90 were considered excellent [32]. The comparison of scores between the initial and retest assessments was evaluated using a Bland-Altman plot [33]. The absolute reliability was evaluated using the standard error of the measurement (SEM) and minimal detectable change (MDC) [32, 34]. While SEM was computed by multiplying the pooled standard deviations from the initial and retest assessments by the square root of 1 minus the reliability of the scores, MDC was calculated by multiplying SEM by the square root of 2 and 1.96 [32, 34]. The change reflects a difference beyond measurement error [32].
Validity
Convergent validity was assessed by examining the relationship between the T-MDADI and the T-SWAL-QOL. Pearson’s correlation coefficients were calculated to evaluate the strength and direction of the associations between corresponding subdomains (e.g., emotional subscale of T-MDADI and mental health subscale of T-SWAL-QOL) and composite scores. Correlation coefficients (r) were interpreted as follows: 0–0.20 = poor, 0.21–0.40 = fair, 0.41–0.60 = good, 0.61–0.80 = very good, and 0.81–1.00 = excellent [35].
Results
A total of 159 patients with neurological disease were enrolled in this study. Thirty-five patients were excluded (illiterate = 9, no reporting swallowing difficulty = 17, having acute medical illnesses = 4 (laryngitis = 1, oral ulcer = 2, pharyngitis = 1), Mini-Mental State Examination score <24 = 5). One hundred twenty-four patients (77 female and 47 male) completed the study. The mean age of the patients was 56.79 ± 14.91 years, range, 23–82 years). Cerebrovascular disease was the most frequently observed disease in the patient group (31.5%). All patients completed a retest assessment 1 week later. The baseline patient characteristics are presented in Table 1.
Demographic and clinical characteristics of patients (n = 124)
Characteristics . | n (%) . |
---|---|
Gender | |
Male | 47 (37.9) |
Female | 77 (62.1) |
Education | |
Primary school | 41 (33.1) |
Secondary school | 42 (33.9) |
High school | 26 (21.0) |
University | 15 (12.1) |
Diagnosis | |
Cerebrovascular disease | 39 (31.5) |
Multiple sclerosis | 32 (25.8) |
Myasthenia gravis | 21 (16.9) |
Guillain-Barre syndrome | 11 (8.9) |
Ataxia | 7 (5.6) |
Amyotrophic lateral sclerosis | 6 (4.8) |
Parkinson’s disease | 4 (3.2) |
Multifocal motor neuropathy | 4 (3.2) |
Characteristics . | n (%) . |
---|---|
Gender | |
Male | 47 (37.9) |
Female | 77 (62.1) |
Education | |
Primary school | 41 (33.1) |
Secondary school | 42 (33.9) |
High school | 26 (21.0) |
University | 15 (12.1) |
Diagnosis | |
Cerebrovascular disease | 39 (31.5) |
Multiple sclerosis | 32 (25.8) |
Myasthenia gravis | 21 (16.9) |
Guillain-Barre syndrome | 11 (8.9) |
Ataxia | 7 (5.6) |
Amyotrophic lateral sclerosis | 6 (4.8) |
Parkinson’s disease | 4 (3.2) |
Multifocal motor neuropathy | 4 (3.2) |
Feasibility
The patients did not miss any survey items during both the initial and retest assessments. Most patients completed the questionnaire within a timeframe of 5–10 min. T-MDADI showed 100% feasibility for the study population (n = 124).
Floor and Ceiling Effects
No notable floor or ceiling effects were noted for any T-MDADI subscale (Table 2).
Cronbach’s a coefficient, average inter-item correlation coefficients, and floor and ceiling effects of T-MDADI (n = 124)
T-MDADI domains . | Items, n . | Cronbach’s alpha coefficient . | Average inter-item correlation coefficient . | Floor effect, % . | Ceiling effect, % . |
---|---|---|---|---|---|
Global | 1 | - | - | 8.1 | 9.6 |
Emotional | 6 | 0.94 | 0.90 | 0 | 2.4 |
Functional | 5 | 0.89 | 0.82 | 0 | 0 |
Physical | 8 | 0.93 | 0.88 | 0 | 0 |
Composite | 19 | 0.96 | 0.93 | 0 | 0 |
T-MDADI domains . | Items, n . | Cronbach’s alpha coefficient . | Average inter-item correlation coefficient . | Floor effect, % . | Ceiling effect, % . |
---|---|---|---|---|---|
Global | 1 | - | - | 8.1 | 9.6 |
Emotional | 6 | 0.94 | 0.90 | 0 | 2.4 |
Functional | 5 | 0.89 | 0.82 | 0 | 0 |
Physical | 8 | 0.93 | 0.88 | 0 | 0 |
Composite | 19 | 0.96 | 0.93 | 0 | 0 |
T-MDADI, Turkish version of the M.D. Anderson Dysphagia Inventory.
Reliability
All patients successfully completed the retest assessment of the T-MDADI 7 days after the initial evaluation. Cronbach’s alpha coefficients, calculated for each subdomain and the composite score, demonstrated excellent internal consistency. The results showed values of 0.94 for the emotional subscale, 0.89 for the functional subscale, 0.93 for the physical subscale, and 0.96 for the composite score. The global subdomain was excluded from this analysis as it consists of only 1 item. Table 2 provides Cronbach’s alpha values for each item in the T-MDADI. Test-retest reliability was assessed using intraclass correlation coefficients (ICCs), which also indicated strong reliability. The ICC values were 0.95 for the global score, 0.90 for the emotional subscale, 0.81 for the functional subscale, 0.88 for the physical subscale, and 0.93 for the composite score. The mean T-MDADI scores for the initial and retest assessments and the ICC determined for the initial-retest assessment reliability with a 95% confidence interval are shown in Table 3.
Test-retest reliability of T-MDADI (n = 124)
T-MDADI domains . | Initial assessment, mean±SD . | Retest assessment, mean±SD . | p value . | ICC2,1 (95% CI) . | SEM . | MDC95 . |
---|---|---|---|---|---|---|
Global (0–100) | 47.41±24.39 | 47.90±24.43 | 0.60 | 0.95 (0.93–0.96) | 5.31 | 14.73 |
Emotional (0–100) | 62.84±16.23 | 62.87±16.96 | 0.96 | 0.90 (0.86–0.93) | 3.20 | 8.86 |
Functional (0–100) | 66.96±15.07 | 64.67±13.23 | 0.04 | 0.81 (0.75–0.87) | 6.10 | 16.9 |
Physical (0–100) | 49.97±16.06 | 50.80±14.80 | 0.23 | 0.88 (0.83–0.91) | 5.19 | 14.40 |
Composite (0–100) | 61.01±15.42 | 60.78±14.96 | 0.65 | 0.93 (0.91–0.95) | 3.96 | 10.97 |
T-MDADI domains . | Initial assessment, mean±SD . | Retest assessment, mean±SD . | p value . | ICC2,1 (95% CI) . | SEM . | MDC95 . |
---|---|---|---|---|---|---|
Global (0–100) | 47.41±24.39 | 47.90±24.43 | 0.60 | 0.95 (0.93–0.96) | 5.31 | 14.73 |
Emotional (0–100) | 62.84±16.23 | 62.87±16.96 | 0.96 | 0.90 (0.86–0.93) | 3.20 | 8.86 |
Functional (0–100) | 66.96±15.07 | 64.67±13.23 | 0.04 | 0.81 (0.75–0.87) | 6.10 | 16.9 |
Physical (0–100) | 49.97±16.06 | 50.80±14.80 | 0.23 | 0.88 (0.83–0.91) | 5.19 | 14.40 |
Composite (0–100) | 61.01±15.42 | 60.78±14.96 | 0.65 | 0.93 (0.91–0.95) | 3.96 | 10.97 |
T-MDADI, Turkish version of the M.D. Anderson Dysphagia Inventory, ICC, intraclass correlation coefficient; SEM, standard error of measurement; MDC, minimal detectable change.
There was no apparent trend indicating increased or decreased discrepancy with higher or lower T-MDADI composite scores, as depicted in a Bland-Altman plot (shown in Fig. 1). The SEM for the T-MDADI composite scores was 3.96, while the MDC was 10.97. The SEM and MDC values for all subdomains of the T-MDADI are presented in Table 3.
Bland-Altman plot of the Turkish version of the MDADI. The central line represents the mean difference between initial test and retest scores, and the outer reference lines represent the 95% limits of agreement.
Bland-Altman plot of the Turkish version of the MDADI. The central line represents the mean difference between initial test and retest scores, and the outer reference lines represent the 95% limits of agreement.
Validity
All subdomains of T-SWAL-QOL showed statistically significant correlations with the T-MDADI subdomains and composite scores (Table 4). The subdomains and composite scores of the T-MDADI showed a very good correlation with the food selection, mental health, and social functioning subdomains of T-SWAL-QOL. Additionally, the subdomains and composite score of the T-MDADI demonstrated a fair correlation with the sleep and fatigue subdomains of the T-SWAL-QOL. Further details are provided in Table 4.
Correlation coefficients between the subdomains of the T-MDADI and subdomains of the T-SWAL-QOL (n = 124)
Questionnaire . | T-MDADI . | ||||
---|---|---|---|---|---|
global . | emotional . | functional . | physical . | composite score . | |
T-SWAL-QOL | |||||
General burden | 0.443b | 0.660b | 0.489b | 0.544b | 0.620b |
Food selection | 0.669b | 0.665b | 0.610b | 0.775b | 0.763b |
Eating duration | 0.508b | 0.659b | 0.396b | 0.510b | 0.587b |
Eating desire | 0.265b | 0.468b | 0.244b | 0.339b | 0.389b |
Fear of eating | 0.422b | 0.504b | 0.407b | 0.386b | 0.477b |
Sleep | 0.339b | 0.308b | 0.394b | 0.228a | 0.332b |
Fatigue | 0.215a | 0.397b | 0.224a | 0.202a | 0.280b |
Communication | 0.533b | 0.623b | 0.307b | 0.411b | 0.510b |
Mental health | 0.616b | 0.789b | 0.615b | 0.715b | 0.785b |
Social functioning | 0.643b | 0.744b | 0.658b | 0.646b | 0.753b |
Frequency of symptoms | 0.574b | 0.544b | 0.443b | 0.509b | 0.565b |
Questionnaire . | T-MDADI . | ||||
---|---|---|---|---|---|
global . | emotional . | functional . | physical . | composite score . | |
T-SWAL-QOL | |||||
General burden | 0.443b | 0.660b | 0.489b | 0.544b | 0.620b |
Food selection | 0.669b | 0.665b | 0.610b | 0.775b | 0.763b |
Eating duration | 0.508b | 0.659b | 0.396b | 0.510b | 0.587b |
Eating desire | 0.265b | 0.468b | 0.244b | 0.339b | 0.389b |
Fear of eating | 0.422b | 0.504b | 0.407b | 0.386b | 0.477b |
Sleep | 0.339b | 0.308b | 0.394b | 0.228a | 0.332b |
Fatigue | 0.215a | 0.397b | 0.224a | 0.202a | 0.280b |
Communication | 0.533b | 0.623b | 0.307b | 0.411b | 0.510b |
Mental health | 0.616b | 0.789b | 0.615b | 0.715b | 0.785b |
Social functioning | 0.643b | 0.744b | 0.658b | 0.646b | 0.753b |
Frequency of symptoms | 0.574b | 0.544b | 0.443b | 0.509b | 0.565b |
A Pearson’s correlation used.
T-MDADI, Turkish version of M.D. Anderson Dysphagia Inventory; T-SWAL-QOL, Turkish version of Swallowing Quality of Life Questionnaire.
aCorrelation is significant at 0.05 level (two-tailed).
bCorrelation is significant at 0.001 level (two-tailed).
Discussion
This study primarily aimed to evaluate the validity and reliability of the MDADI in Turkish patients with neurological disease. Through successful cross-cultural adaptation and translation, the study found statistically significant results, indicating that the MDADI is a valid and reliable assessment questionnaire for this Turkish population.
Feasibility
The patients in our study exhibited high compliance with the Turkish version of the MDADI, demonstrating no missing item values, indicating its feasibility in clinical settings. These findings align with results from Swedish [16], Arabic [18], and Japanese [13] studies. As noted in previous studies, this result may be attributed to the concise nature of the items in the MDADI compared to other questionnaires [9‒11].
Floor and Ceiling Effects
Assessing floor and ceiling effects is crucial in reliability and validation studies because they can impact the reliability of any questionnaire tool by causing scale attenuation. In our study, no significant floor or ceiling effects were observed in the T-MDADI. Only three other MDADI version studies have previously examined floor and ceiling effects previously [16‒18]. Similar to our findings, no notable floor or ceiling effects were detected in any domain or composite scores of the Arabic version [18]. In the Dutch version [17], no floor effect was identified, but a ceiling effect was detected in the global and functional domains. Similar to the Dutch version, a ceiling effect was determined in the global domain of the Swedish version [16]. Both the Dutch and Swedish versions involve patients with neurological diseases. The disparity in ceiling effects may stem from the disease characteristics of the patients included in the studies and/or the global domain containing only a single item.
Reliability
Reliability assessment determines the consistency or dependability of a construct’s measurement. The T-MDADI demonstrated excellent internal consistency, with Cronbach’s alpha coefficients ranging from 0.89 to 0.96, exceeding the acceptable threshold of 0.70. These values are consistent with other language validations, such as the Arabic (0.92–0.96) and Portuguese (0.89–0.94) versions [18, 24]. The high Cronbach’s alpha values (ranging from 0.89 to 0.96) indicate excellent internal consistency. However, values above 0.90 may suggest potential redundancy among items [36]. While no items were identified as redundant based on the current analysis, this warrants further investigation through methods like factor analysis in future studies.
Test-retest reliability was equally robust, with ICC values ranging from 0.81 to 0.95, which falls within the range reported in the Japanese and French studies [13, 23]. The additional evaluation of SEM and MDC further supports the reliability of the Turkish version. SEM values (3.96 for the composite score) suggest low measurement error, while MDC values (10.97 for the composite score) indicate the scale’s sensitivity in detecting clinically meaningful changes over time. These findings are consistent with those of previous studies investigating the SEM and MDC values for MDADI [14, 23] and affirm the robustness of the T-MDADI for use in Turkish neurological populations.
Validity
Validity refers to how accurately a measure represents the underlying construct that it is intended to assess [35]. In our study, convergent validity was reported by comparing the MDADI and T-SWAL-QOL domains. The T-MDADI demonstrated good convergent validity, with significant correlations between its subdomains and the corresponding subdomains of the T-SWAL-QOL. Particularly strong correlations were observed with the food selection, mental health, and social functioning subdomains, highlighting the relevance of the T-MDADI in capturing key aspects of dysphagia-related QoL. These results align with previous validations of the MDADI in Dutch [17], Chinese [19], and Portuguese [21] populations, further underscoring its cross-cultural applicability. However, weaker correlations with fatigue and sleep subdomains suggest these domains may be less directly influenced by dysphagia-specific factors.
Despite its strengths, this study has limitations. First, the heterogeneity of the patient population, which included individuals with various neurological conditions, may have introduced variability in responses. While this diversity increases the generalizability of the findings, it may obscure condition-specific differences in dysphagia-related QoL. Future studies should include subgroup analyses to address this issue. Second, factor analysis was not conducted, which limits the ability to confirm the scale’s structural validity. Finally, while the sample size was adequate for validation purposes, larger and more diverse cohorts are needed to strengthen the generalizability of the results and further explore the psychometric properties of the T-MDADI.
Conclusion
The T-MDADI is a valid, reliable, and culturally adapted instrument that fills a critical gap in the assessment of dysphagia-related QoL in Turkey. It has the potential to improve the evaluation and management of dysphagia in clinical practice and research, contributing to better patient outcomes and quality of care. Future studies should aim to build upon these findings, ensuring the continued refinement and application of this important tool in diverse patient populations.
Acknowledgments
We would like to express our gratitude to Dr. Amy Y. Chen (Emory University, USA) for giving us permission to translate and validate the original MDADI questionnaire.
Statement of Ethics
This study protocol was reviewed and approved by the Gazi University Ethics Committee (registration number 2023-1441), conducted in accordance with the Declaration of Helsinki, and registered at ClinicalTrials.gov (registration number: NCT06197451). All participants agreed to participate in the study and signed a written informed consent form. All procedures performed in this study involving human participants were in accordance with the ethical standards of the Institutional and/or National Research Committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards.
Conflict of Interest Statement
The authors have no competing interests to declare.
Funding Sources
No financial support was received for the research, authorship, or publication of this study.
Author Contributions
Material preparation, data collection, and analysis were performed by Muserrefe Nur Keles, Ozgu Inal Ozun, Tulin Gesoglu Demir, Serife Gizem Sarioglu Ermumcu, and Nihat Sengeze, respectively. Muserrefe Nur Keles drafted the first version of the manuscript. All authors reviewed and provided comments on subsequent versions, have read and approved the final manuscript, and contributed to the conception and design of the study.
Data Availability Statement
The data that support the findings of this study are not publicly available as they contain information that could compromise the privacy of research participants. However, the data are available from the corresponding author, M.N.K. ([email protected]), upon reasonable request.