Cultural Differences Impact Subjective Experience of Dyskinesias in Parkinson Disease

Valtteri Kaasinen, MD, PhD

A recent study published in the journal of Movement Disorder revealed significant differences in the prevalence and severity of dyskinesias, a common side effect of Parkinson disease (PD) medication, across the span of multiple cultures and languages. The findings suggest that cultural factors may play a role in the development and severity of dyskinesias in patients with PD.¹

Compared with other languages, the Chinese Perception Severity Index (PSI) was higher for (P <.008) and the Korean ratio was lower than the Turkish, Finnish, German, Polish, Greek, and Japanese ratios (P <.011). In addition, Hebrew and Slovakian languages scored significantly higher than other languages on both objective and subjective ratings (all P values <.001; all P values ≤0.027).

Lead author Valtteri Kaasinen, MD, PhD, professor of neurology, University of Turku, Finland, and colleagues wrote, "It is noteworthy that opposite differences were seen in two Asian languages/cultures, which underlines the trend being present even between geographical regions that are relatively close. This finding emphasizes the importance of cultural sensitivity and the high risk of coalescing cultures simply based on global location or broad racial assumptions."

Across various countries worldwide, researchers collected and analyzed data from 3566 patients with PD who were diagnosed with levodopa-induced dyskinesia (LID). For the analysis, PSI was used for comparing the prevalence of dyskinesias across different languages and cultures of patients. The study also used the International Parkinson and Movement Disorder Society (MDS)–based Clinical Outcome Assessment Program Translation dataset, which included 4134 complete ratings and 16 different languages. A minimum of 250 cases of each language were contributed to the database. Data from 14 languages were collected from individual countries, and 2 were from more than one country.

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Objective Italian scores were higher than Turkish scores (P = 0.008) and Turkish scores were lower than French and Portuguese scores (all P values ≤.004). Chinese scores were lower compared with those for Japanese, Italian, Spanish, French, Hungarian, Greek, Portuguese, Russian, and Polish (all P values ≤.016). Subjective dyskinesia scores were different across languages (F[15:2177] = 29.3; P <.001). Korean subjective scores were lower than those of all other languages (all P values <.001) and Hebrew had higher subjective scores than those of all other languages (all P values ≤.014), except Slovakian, for where no difference was observed. No systematic differences between large geographical regions were observed, such as intercontinental differences between Western and Eastern cultures, as was reported for nonmotor symptoms of PD in previous research.^2,3

"Our results also showed differences in objective clinician-observed and subjective patient-reported levels of dyskinesia between language areas. However, these differences are mostly likely related to general sampling differences. For instance, Hebrew and Slovakian languages scored significantly higher than other languages on both objective and subjective ratings, suggesting that the patient samples for these regions included higher numbers of severely dyskinetic patients than those for other languages (eg, German)," Kaasinen et al noted.¹

The study did not include all languages and cultures, and therefore the findings may not be generalizable to all patients with PD globally. Authors noted that further research is needed to understand these cultural differences and their impact on treatment outcomes for the development of culturally sensitive interventions. Another limitation is that the study did not investigate the underlying mechanisms that may provide explanation for the cultural differences in dyskinesias, such as factors pertaining to genetics or the environment.

Authors also noted that longitudinal studies could be conducted for determining how dyskinesias change over time and the respond to different treatments across different cultures. All told, other factors that could be explored could be age, gender, and disease duration which might also impact the prevalence and severity of dyskinesias.

"In conclusion, our study provides evidence that cultural factors may influence how patients experience dyskinesias in PD across different languages and cultures. These findings have important implications for clinical practice and research on PD worldwide," Kaasinen et al noted.¹

REFERENCES
1. Kaasinen V, Luo S, Martinez-Martin P, Goetz CG, Stebbins GT. Cross-Cultural Differences in Patient Perceptions of Dyskinesia in Parkinson's Disease. Mov Disord. 2023;38(4):688-692. doi:10.1002/mds.29335
2. Yu RL, Wu RM, Chan AY, et al. Cross-Cultural Differences of the Non-Motor Symptoms Studied by the Traditional Chinese Version of the International Parkinson and Movement Disorder Society- Unified Parkinson's Disease Rating Scale. Mov Disord Clin Pract. 2017;4(1):68-77. doi:10.1002/mdc3.12349
3. Sauerbier A, Aris A, Lim EW, Bhattacharya K, Ray Chaudhuri K. Impact of ethnicity on the natural history of Parkinson disease. Med J Aust. 2018;208(9):410-414. doi:10.5694/mja17.01074