Doctoral Defense in Health Sciences - Íris Ösp Bergþórsdóttir

On Friday, March 21, 2025, Íris Ösp Bergþórsdóttir will defend her doctoral dissertation in health sciences at the Faculty of Medicine, University of Iceland. The dissertation is titled: Fidelity measurements in home-based intervention studies for children who stutter.

Opponents are Dr. Belinda Borrelli, Professor and Director of the Center for Behavioral Science at Boston University, and Dr. Anna Lind G. Pétursdóttir, Professor at the School of Education, University of Iceland.

The supervisor was Jóhanna Thelma Einarsdóttir, Professor, and the co-supervisor was Kathryn Margaret Crowe, Associate Professor. Additionally, Þorlákur Karlsson, Associate Professor, was a member of the doctoral committee.

Þórarinn Guðjónsson, Professor and Dean of the Faculty of Medicine, will preside over the ceremony, which will take place in the Ceremonial Hall of the University of Iceland, beginning at 9:00 AM.

Abstract

Fidelity of Implementation (FOI) measures how well an intervention is delivered as intended, which is crucial for evaluating its effectiveness. This thesis examines how FOI influences intervention outcomes, focusing on stuttering interventions for children in home settings. It aims to understand FOI reporting in previous studies, evaluate a pilot home-based stuttering intervention (STOC) with detailed FOI measurements, achieve high FOI in a controlled study, and determine the relationship between FOI and outcomes in school-aged children who stutter.

The research involved a systematic literature review of 36 papers (1981-2021) analyzing four FOI components: dosage, adherence, quality, and responsiveness. A single case experimental design was used with seven children (9-13 years) for the STOC intervention, monitored over 18-30 months. The intervention sessions were evaluated based on the four FOI components.

Results showed inconsistent FOI reporting, with dosage most frequently reported and responsiveness least reported. The STOC pilot study demonstrated reduced stuttering and improved fluency and quality of life for participants. Higher dosage and adherence were linked to better outcomes, while quality and responsiveness increased speech output but didn't reduce stuttering.

In conclusion, poor FOI reporting in stuttering research hinders accurate interpretation of findings. The STOC study showed that better adherence leads to improved outcomes. Comprehensive FOI examination can provide insights into intervention variability, highlighting the need for thorough FOI measurement and reporting in future studies.

About the Doctoral Candidate

Íris Ösp Bergþórsdóttir was born in 1977 in Reykjavík. She graduated from the sociology track at Kvennaskólinn in Reykjavík in 1997 and obtained a BA degree in psychology from the University of Iceland in 2001. She later earned a master’s degree in business administration from the University of Iceland in 2013. Íris began her doctoral studies at the School of Education in 2014 but transferred to the School of Health Sciences with her research project in 2019.

Her research received a project grant from the Icelandic Research Fund (RANNÍS) in 2014. She spent part of her studies in Santa Barbara, USA, working under the supervision of Dr. Rogers Ingham for a year. Alongside her doctoral studies, Íris has worked in human resources, both at Icelandair and Elkem Iceland.

Íris is married to Sverrir Þór Sverrisson, and together they have three children: Þórdís Katla, Bergþór Ingi, and Arnaldur Flóki.