Multiple sclerosis is a neurological disease of the central nervous system characterized by micro- and macroscopic areas of demyelination. The onset is primarily between the ages of 20 and 45 years with a wide spectrum of symptoms and signs [
Quality of life is defined as “the individual’s perceptions of their position in life in the context of culture and value system in which they live, and in relation to their goals, expectations, standards and concerns” as defined by the WHO [
Assessment of health related quality of life in patients with MS is important not only in research but also in clinical practice because it allows better decision making in the management and care policy in this group of patients. Several studies have reviewed the impact of multiple sclerosis on health related quality of life in relation to pain symptoms, cognitive function, depression, fatigue, disability, effect of medications, and others [
The purpose of this study is to investigate the voice related quality of life in a large group of patients with multiple sclerosis. The Voice Handicap Index, one of many patient-reported outcome measures that have gained popularity in both the clinical and research milieus, will be used in this investigation.
A total of 87 subjects were asked to participate in this study after having read and signed the informed consent approved by the Institutional Review Board.
Confidentiality was maintained throughout the data collection process. All data was kept under lock and key and it was accessible only to the principle investigator and his research team.
Subjects with recent history of upper respiratory tract infection, laryngeal manipulation, or previous laryngeal surgery were excluded from this study. The subjects were divided into two groups, one with MS consisting of 59 subjects and one as control consisting of 28 healthy subjects matched according to age and gender. Patients with MS were referred from the private clinic of the neurology service.
Demographic variables included age, gender, and history of smoking. Other variables taken included presence or absence of phonatory symptoms, duration of the disease in months, the expanded disability status scale (EDSS) reflecting the severity of the disease, the severity of fatigue, and depression. The type of the disease was classified according to the progression of the disease as relapsing remitting (RRMS), secondary progressive (SPMS), relapsing/progressive (RPMS), and primary progressive (PPMS). For the disability status, a score between 0 and 3 was considered mild, between 3.5 and 6 as moderate, and above 6 as severe [
All patients were asked to fill the Voice Handicap Index. It is a patient-based self-assessment tool that consists of 30 items distributed over three domains: functional, physical, and emotional. The functional subscale describes the “impact of voice disorders on daily activities,” the physical subscale describes patients’ self-perceptions of laryngeal discomfort or the voice output characteristics, and the emotional subscale illustrates patients, “affective response to voice disorders”. The VHI total score ranges between 0 and 120 a high number indicates greater severity of voice problem [
Demographic characteristics of the participants were examined separately for cases and controls using frequency distributions for categorical variables (gender, smoking and type of MS) and means with standard deviations for continuous ones (age, duration of MS, EDSS, FSS score, and HRSD).
The differences between cases and controls in terms of VHI total score and subscores (VHI P, VHI F, and VHI E) were calculated using independent samples
A total of 59 patients with MS were enrolled in this study. The average age was 35.47 years + 10.92 with 39% being males. Close to 90% were in the RRMS stage of the disease, and the average duration of the disease was 77.93 months. The EDSS score was
Demographics.
Variables | Cases |
Control |
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Mean | SD | Mean | SD | |
Age | 35.47 | 10.92 | 33.25 | 11.47 |
Duration of MS (months) | 77.93 | 79.82 | N/A | N/A |
EDSS | 1.94 | 1.84 | N/A | N/A |
FSS score | 4.07 | 2.09 | 2.22 | 0.94 |
HRSD | 7.28 | 7.70 | 3.18 | 3.12 |
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% |
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% | |
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Gender (% male) | 23 | 39.0 | 11 | 39.3 |
Smoking (% yes) | 24 | 40.7 | 8 | 28.6 |
Type of MS | ||||
RRMS | 52 | 89.7 | N/A | N/A |
SPMS | 6 | 10.3 | N/A | N/A |
Phonatory symptoms | 7 | 11.9 | 3 | 10.7 |
*Some numbers do not add up to the total because of missing values.
The mean score for the VHI in the diseased group was
Difference between cases and control in terms of VHI scores.
Variables | Cases | Control |
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||
---|---|---|---|---|---|
Mean | ±SD | Mean | ±SD | ||
VHI total | 5.92 | 15.47 | 5.32 | 8.21 | 0.849 |
VHI P | 2.36 | 5.36 | 1.86 | 2.92 | 0.647 |
VHI F | 2.15 | 5.37 | 2.18 | 3.48 | 0.981 |
VHI E | 1.41 | 5.60 | 1.29 | 2.80 | 0.914 |
Among cases, there was a positive correlation between VHI total score and FSS score and HRSD (
Association of VHI scores with selected variables among cases.
Variables | VHI total | VHI P | VHI F | VHI E | ||||
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Correlation coefficient ( |
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Correlation coefficient ( |
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Correlation coefficient ( |
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Correlation coefficient ( |
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|
FSS score | 0.331 | 0.011 | 0.349 | 0.007 | 0.319 | 0.014 | 0.273 | 0.036 |
HRSD | 0.505 | <0.001 | 0.554 | <0.001 | 0.478 | <0.001 | 0.407 | 0.001 |
EDSS score | −0.035 | 0.803 | 0.030 | 0.832 | −0.053 | 0.703 | −0.073 | 0.599 |
Disease duration | 0.093 | 0.486 | 0.163 | 0.222 | 0.059 | 0.660 | 0.045 | 0.736 |
Association of VHI scores with selected variables among controls.
Variables | VHI total | VHI P | VHI F | VHI E | ||||
---|---|---|---|---|---|---|---|---|
Correlation coefficient ( |
|
Correlation coefficient ( |
|
Correlation coefficient ( |
|
Correlation coefficient ( |
|
|
FSS score | −0.229 | 0.240 | −0.291 | 0.132 | −0.171 | 0.385 | −0.176 | 0.370 |
HRSD | −0.072 | 0.716 | 0.005 | 0.979 | −0.077 | 0.698 | −0.109 | 0.580 |
The voice is a sensitive neurophysiological signal that reflects the status of the nervous system and its pathways. It is well recognized that MS is a condition that can negatively affect voice and health related quality of life in various domains [
Understanding the quality of life in relation to specific diseases and systems can be used as a predictive factor for the development of any disease and for the advancement in its treatment. There are several reports in the literature investigating the association between MS disabilities and impairment in relation to quality of life. In Rudick et al.’s report on the relationship between disease activity and health related quality of life in relapsing multiple sclerosis, the mean baseline SF-36 scores were significantly less than the general population and correlated with Expanded Disability Status Scale scores, sustained disability progression, relapse number, and increased volume of brain magnetic resonance imaging lesions [
Although commonly masked by speech disorder, vocal symptoms such as vocal fatigue, voice breaks, and phonatory instability still prevail in multiple sclerosis with little knowledge of their impact on life. The prevalence of phonatory symptoms varies in various reports and one-third of patients with MS can have varying degree of dysphonia compared to 7.4% of controls. Other studies have reported a prevalence rate of 70% versus 33% of controls [
Despite the fact that vocal dysfunction is often reported in patients with multiple sclerosis, the voice related quality of life in MS patients remains unknown. The authors of this paper have chosen the VHI, one of the strongest psychometric measures, as a patient-reported outcome measure of voice related quality of life [
The results of our study revealed that the mean score of the VHI total was less than 20 meaning that voice related quality of life is normal with no major impact. The results further indicate that there is no significant difference in the mean score of VHI in MS patients and controls. Our results are not in accordance with those of Chiari et al. In their study on 17 participants with MS, the effect of expiratory muscle strength training on maximal expiratory pressure and voice was investigated [
The low VHI scores in our diseased patients could be attributed to several factors. First is the little disability in our diseased group as indicated by the low EDSS score below 3 reflecting mild if any disability, even though one can argue that the prevalence of phonatory symptoms is not associated with the EDSS score as previously reported by the authors of this paper 19. Second is the stage of the disease as most of our patients, close to 90%, were in the relapsing/remitting stage, and last but not least is the low fatigue severity score 4.02, further indicating the relatively minimal fatigability experienced by the MS patients.
What is important to note in our investigation is the correlation between the total VHI score and sub scores with the FSS and HRSD score among cases, as indicated, for instance that the FSS score (fatigue) explains 33% of the VHI score and HRSD (depression) explains a 50%. This correlation is easy to understand given that voice is a reflection of the entire being and thus infers the overall physical and emotional status of the individual. With respect to the association with the fatigability severity scale
With respect to the association between VHI scores and depression, several studies have confirmed the correlation between mental status and voice. In a study by Park CK et al., mood status of young subjects could be estimated using acoustic parameters [
This study carries two limitations. First is the lack of an objective outcome measure for voice such as acoustic analysis, and second is the lack of laryngeal examination. However it is worth noting that the purpose of this investigation was to measure the voice related quality of life as perceived by the patient and not the physician. For that purpose, the Voice Handicap Index was used in all subjects with MS with no input from the treating physician. Our results indicate that vocal symptoms, when reported by the patient, are not that common and have little impact if any on the quality of life.
The prevalence of dysphonia in patients with MS is low when patient-reported outcome measures such as the VHI are used. The voice related quality of life in MS is within normal with no disability.
No conflict of interests or financial support in relation to this paper is declared.