The Parkinson's Disease Sleep Scale-2 (PDSS-2): Validation of the Spanish Version and Its Relationship With a Roommate-Based Version

Cross-cultural adaptation and measurement properties of the Brazilian Portuguese version of the Parkinson's disease sleep scale-2 (PDSS-2)

OBJECTIVES

The Parkinson's Disease Sleep Scale-2 (PDSS-2) is an updated tool designed to identify specific sleep disturbances in individuals with Parkinson's disease (PD). However, for its application in Brazil, a process of cross-cultural adaptation and validation of its measurement properties is required.

METHODS

This methodological study adapted the PDSS-2 to Brazilian Portuguese (PDSS-2-Br) and assessed its measurement properties, including internal consistency, test-retest reliability, measurement error, construct validity, and interpretability. The adapted scale was administered on two occasions within a 7-day interval to 50 individuals with PD. Test-retest reliability was evaluated using kappa statistics (k) for individual items, the intraclass correlation coefficient (ICC) for total scores, the standard error of measurement (SEM), the minimal detectable change (MDC), and a Bland-Altman plot. Construct validity was assessed through Spearman correlation coefficients between the PDSS-2-Br and independent variables, while interpretability was evaluated by examining ceiling and floor effects.

RESULTS

The PDSS-2-Br showed satisfactory semantic, idiomatic, cultural, and conceptual equivalence. It also demonstrated good internal consistency (α=0.64), adequate test-retest reliability between items (κw 0.42-0.94, 95 % CI=0.30-0.95) and total score (ICC=0.94; 95 % CI=0.89-0.96), acceptable measurement error (SEM, 2.07 points; MDC, 5.74 points), with no ceiling and floor effects, and 87.5 % of pre-defined hypotheses were confirmed, indicating adequate construct validity (Spearman correlations coefficients for the rs=0.50, p<0.001) of the PDSS-2-Br.

CONCLUSION

The measurement properties of the PDSS-2-Br are consistent with those of the original version, confirming the scale's validity and reliability in assessing sleep disorders among the Brazilian population with PD.

Validation of the Arabic version of Parkinson's Disease Sleep Scale-Revised Version (PDSS-2)

OBJECTIVES

Parkinson's disease sleep scale (PDSS) was recommended by the Movement Disorder Society task force for screening and grading the severity of sleep problems in Parkinson's disease (PD). This work aimed to examine the validity and reliability of an Arabic version of PDSS-2.

METHODS

This cross-sectional study was carried out on 133 patients fulfilling diagnostic criteria for PD. The patients were clinically assessed using the following scales: Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS), modified Hoehn and Yahr Scale (H&Y), non-motor symptoms scale (NMSS), Beck Depression Inventory (BDI), and Pittsburgh Sleep Quality Index (PSQI). PDSS-2 scale was translated according to approved translation standards into Arabic and back-translated into English. Patients were asked to respond based on their experience in the last week.

RESULTS

The mean PDSS2 score for the included PD patients was 17±10. Cronbach's α coefficient value was 0.89, indicating good internal consistency. Most items showed high item-total correlation; the lowest was 0.375, considered higher than the conventional cut-off of 0.3. Test-retest reliability showed good agreement (ICC: 0.848). The exploratory factor analysis showed that items had been loaded over four factors. Total PDSS-2 score was positively correlated to age, disease duration, modified H&Y scale, MDS-UPDRS, NMSS, BDI, and global PSQI score. A cut-off point of 13 could differentiate poor sleepers from good sleepers with 91% sensitivity and 70% specificity (AUC 0.893, P<0.001).

CONCLUSION

The Arabic version of PDSS-2 has appropriate validity and can be reliably used for assessing sleep-related problems in Arabic-speaking patients with PD.

Translation of Parkinson's Disease Sleep Scale-2 (PDSS-2) in Hindi (H-PDSS-2) and its Validation for Assessment of Sleep Disturbances among Indian Parkinson's Disease Patients

Background and Objective

Parkinson's disease sleep scale-2 (PDSS-2) is a reliable sleep assessment tool which has been validated in several languages. As sleep problems have a great impact on the quality of life of Parkinson's disease patients, we aimed to translate and validate PDSS-2 in Hindi for its wider use among Hindi-speaking Indian patients. Our study objective was to translate PDSS-2 in Hindi (H-PDSS-2) and to assess the psychometric properties of H-PDSS-2 questionnaire for its use in Hindi-speaking Indian PD patients. Secondly, we aimed to compare the results with those of the other language PDSS-2 validation studies.

Material and Methods

This study was done in two phases, enrolling 16 patients and 16 controls in the first/translation phase for assessment of internal consistency and discriminative power of PDSS-2. The test-retest reliability was determined in the second phase on 35 Parkinson's disease patients who were followed-up at an interval of 7-10 days.

Results

No difficulties were faced by the patients and controls in the first phase, and internal consistency of the scale was good (Cronbach's alpha = 0.804). There was no significant difference in total H-PDSS-2 score at baseline 16.86 ± 10.59 and on retest 16.40 ± 9.54, suggesting good reliability. Intraclass correlation coefficients ranged from 0.710 to 0.901, and precision was 2.82 over the period of 7-10 days. Subdomains of H-PDSS-2 had moderate/high internal validity, and they showed significant correlation with Unified PD Rating Scale (UPDRS) and HY disease scale.

Conclusion

H-PDSS-2 is equivalent to the original PDSS-2 for tested psychometric attributes. Its use among Indian Parkinson's disease patients will help in the comprehensive assessment of sleep problems among PD patients.

Lack of direct association between viral hepatitis and sleep disturbances

Background

Individuals with chronic viral hepatitis are at increased risk of experiencing poor sleep quality and sleep disturbances. However, it remains unclear whether the sleep disorders associated with viral hepatitis are secondary to the comorbidities related to viral hepatitis or the direct effect of hepatitis viruses on sleep. This study investigated the direct impact of viral hepatitis B and C on sleep quality.

Methods

Individuals with viral hepatitis B or C and their healthy counterparts were recruited for the present study, and they were evaluated with the Parkinson's Disease Sleep Scale-2, the Epworth Sleepiness Scale, and the Pittsburgh Sleep Quality Index in the absence of common comorbidities associated with viral hepatitis.

Results

Neither hepatitis B nor hepatitis C was found to cause significant differences in insomnia symptoms or excessive daytime sleepiness. However, individuals with hepatitis C, but not hepatitis B, tended to be less likely to experience restlessness of the legs or arms at night.

Conclusions

This study suggests that hepatitis viruses B and C may not cause a significant impact on sleep quality and related disorders directly. Sleep disturbances in individuals with chronic viral hepatitis may instead be attributable to hepatic decompensation or the comorbid factors associated with viral hepatitis.

Personalized Assessment of Insomnia and Sleep Quality in Patients with Parkinson's Disease

Sleep disturbances are more common in patients with Parkinson’s disease (PD) than in the general population and are considered one of the most troublesome symptoms by these patients. Insomnia represents one of the most common sleep disturbances in PD, and it correlates significantly with poor quality of life. There are several known causes of insomnia in the general population, but the complex manifestations that might be associated with PD may also induce insomnia and impact the quality of sleep. The treatment of insomnia and the strategies needed to improve sleep quality may therefore represent a challenge for the neurologist. A personalized approach to the PD patient with insomnia may help the clinician to identify the factors and comorbidities that should also be considered in order to establish a better individualized therapeutic plan. This review will focus on the main characteristics and correlations of insomnia, the most common risk factors, and the main subjective and objective methods indicated for the assessment of insomnia and sleep quality in order to offer a concise guide containing the main steps needed to approach the PD patient with chronic insomnia in a personalized manner.

Validity and Reliability of the Persian Version of Parkinson's Disease Sleep Scale-2

OBJECTIVE

Sleep problems are nonmotor symptoms in Parkinson's disease that should be carefully evaluated for better management and treatment. Parkinson's Disease Sleep Scale (PDSS-2) is one of the most reliable tools for measuring sleep difficulties in people with Parkinson's disease. This study investigated the psychometric properties of the Persian version of PDSS-2.

METHODS

Four hundred and fifty-six people with Parkinson's disease with a mean age ±standard deviation of 60.7 ± 11.3 years were engaged in this study. Acceptability was assessed by floor and ceiling effects. Dimensionality was measured by exploratory factor analysis. The convergent validity of PDSS-2 with the Hospital Anxiety and Depression Scale (HADS) was assessed. Internal consistency and test-retest reliability were assessed with Cronbach's alpha and intraclass correlation coefficient (ICC), respectively.

RESULTS

No noticeable ceiling and floor effect was detected. The dimensionality analysis showed three factors. A high correlation was obtained between PDSS-2 and HADS (anxiety subscale). Excellent internal consistency with α = 0.94, and good test-retest reliability with ICC = 0.89 were obtained.

CONCLUSION

This study showed that the Persian version of Parkinson's Disease Sleep Scale has acceptable validity and reliability for measuring sleep disturbances in people with Parkinson's disease.

A holistic approach to evaluating Parkinson's disease, using the Delphi method: a linear evaluation index

BACKGROUND

Parkinson's disease (PD) is a chronic disease that presents a multitude of symptoms, with symptoms of both motor and nonmotor nature. The Delphi method is widely used to create consensuses among experts in a field of knowledge.

OBJECTIVE

In order to reach a consensus on the values that should be assigned to the different motor and nonmotor manifestations of Parkinson's disease, a linear evaluation index (LEI) was created. Subsequently, the metric properties of this index were studied.

METHODS

120 consecutive patients with a Parkinson's diagnosis were chosen in accordance with the UKPDSBB criteria. The Delphi method was used to reach a consensus among experts regarding the values of each of the manifestations included. Subsequently, the following attributes were analyzed: quality and acceptability of the data; reliability, in terms of internal consistency, reliability index, Cronbach's alpha and standard error of measurement; and validity, in terms of convergent validity and validity for known groups.

RESULTS

Twenty-five experts participated. The importance factor did not differ between the first round and the second round (chi-square test). We analyzed the responses that assigned percentage values to the 10 dimensions of the LEI. Both in the first and in the second round, the values of the scattering coefficient Vr were always close to 0. The homogeneity index was 0.36; the corrected-item total correlation values ranged from 0.02 to 0.7; Cronbach's α was 0.69; and the SEM was 4.23 (55.1%).

CONCLUSIONS

The LEI was obtained through rigorous recommended methodology. The results showed adequate metric properties.

Prevalence and profile of nocturnal disturbances in Chinese patients with advanced-stage Parkinson's disease: a cross-sectional epidemiology study

Background

The impact of nocturnal disturbance (ND) in Parkinson’s disease on quality of life of patients in Western Countries is increasingly understood. Our study aimed to investigate ND prevalence and its quality of life impact in patients with advanced Parkinson’s disease in China.

Methods

In a multicenter, tertiary-care hospital, outpatient-based, cross-sectional study, patients with advanced Parkinson’s disease (Modified Hoehn & Yahr [H&Y] Stage II–IV with ≥3 h awake “off” time/day) from 10 tertiary hospitals throughout China completed the Parkinson’s Disease Sleep Scale-2 (PDSS-2) and Parkinson’s Disease Questionnaire-39 (PDQ-39). The primary endpoint was the percentage of patients with significant ND (PDSS-2 total score ≥ 15). Additional endpoints were demographic and clinical characteristics, PDSS-2 and PDQ-39 total and subscale scores, correlation between PDSS-2 and PDQ-39, and risk factors for ND and higher PDSS-2 or PDQ-39 scores.

Results

Of 448 patients analyzed (mean age 63.5 years, 47.3% female), 70.92% (95% confidence interval: 66.71, 75.13) had significant ND. Presence of ND and higher PDSS-2 scores were associated with longer disease duration and higher H&Y stage. Presence of ND was also associated with more awake “off” time/day and female sex. PDQ-39 scores were significantly worse for patients with ND versus those without ND; worse scores were associated with more awake “off” time/day, female sex, and higher H&Y stage. PDSS-2 and PDQ-39 total scores were associated: Pearson correlation coefficient 0.62 (p < 0.001).

Conclusions

In China, ND was highly prevalent in patients with advanced Parkinson’s disease and adversely impacted quality of life. This study highlights the importance of early diagnosis and optimized management of ND in patients with Parkinson’s disease in China.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12883-021-02217-5.