The Voice Foundation Vocal fatigue is a frequent symptom and a debilitating condition affecting individuals with voice disorders. In spite of the various attempts to define and quantify vocal fatigue, this complex trait has not been well understood. Mokken scaling was performed on the Vocal Fatigue Index (VFI) to develop a hierarchical understanding of the latent trait of vocal fatigue. Two hundred nine patients with voice disorders completed the VFI and provided the item responses necessary to complete the Mokken scaling. Results revealed a moderately strong Mokken scale and that the VFI presents a hierarchical structure to the underlying trait of vocal fatigue. Mokken scaling contributes to the ongoing investigation to the underlying construct of vocal fatigue and may provide additional information about specific complaints within the population of those with voice disorders.

Vocal fatigue is a frequent symptom and a debilitating condition affecting individuals with voice disorders. In spite of the various attempts to define and quantify vocal fatigue, this complex trait has not been well understood. Mokken scaling was performed on the Vocal Fatigue Index (VFI) to develop a hierarchical understanding of the latent trait of vocal fatigue. Two hundred nine patients with voice disorders completed the VFI and provided the item responses necessary to complete the Mokken scaling. Results revealed a moderately strong Mokken scale and that the VFI presents a hierarchical structure to the underlying trait of vocal fatigue. Mokken scaling contributes to the ongoing investigation to the underlying construct of vocal fatigue and may provide additional information about specific complaints within the population of those with voice disorders.

This study examines how a user-centered approach can influence product design to reduce physical discomfort when using in-ear true wireless. The given study is a collaboration with the consumer electronics company Zound Industries. The purpose has been to understand the origins of why physical discomfort can arise when using in-ear true wireless headphones and to what extent the user behaviour plays in it all. Previous studies have shown how physical discomfort in the form of eczema, itching and soreness has been caused by the use of in-ear true wireless. Based on user-centered methods such as expert interviews, cultural probes, user interviews, focus groups, this study has been able to identify not only how, but why physical discomfort can occur when using in-ear true wireless. Furthermore, the study has also been able to identify behavioural patterns among users that reveal how headphones are used for purposes other than what they are intended for. It has been possible to show how users use their headphones like an earplug without music to block out sound in order to be able focus or to communicate they don’t want to be disturbed to avoid social interactions. The conducted knowledge and insights provide a better understanding of how design can be used to enhance the experience of using in-ear true wireless headphones. Applying design strategies within design for behavioural change, an adjustable headphone has been developed that allows the user to use the headphone according to the needs of the user. The study provides a basis for how design can be better utilised in future in-ear true wireless headphones.