Ludlow CL, et al. - Authors ascertained the agreement among experts not using standard guidelines to classify patients with abductor spasmodic dysphonia (ABSD), adductor spasmodic dysphonia (ADSD), voice tremor (VT), and muscular tension dysphonia (MTD), and develop expert consensus attributes for classifying patients for research. When classifying patients for research, poor agreement was seen in specialists without guidelines, leading to a Delphi-based development of the Spasmodic Dysphonia Attributes Inventory for classifying patients with ADSD, ABSD, VT, and MTD for research.

Methods

• Experts conducted a multicenter observational study examined agreement among blinded experts when classifying patients with ADSD, ABSD, VT or MTD (first study) from 2011 to 2016.
• Subsequently, in a 4-stage Delphi method study they used reiterative stages of review by an expert panel and 46 community experts to develop consensus on attributes to be used for classifying patients with the 4 disorders (second study).
• In this study, they utilized a convenience sample of 178 patients clinically diagnosed with ADSD, ABSD, VT MTD, vocal fold paresis/paralysis, psychogenic voice disorders, or hypophonia secondary to Parkinson disease.
• The age of the participants was 18 years or more, without laryngeal structural disease or surgery for ADSD and underwent speech and nasolaryngoscopy video recordings following a standard protocol.
• Speech and nasolaryngoscopy video recordings following a standard protocol were the exposures.
• A total of 178 patients were classified into 11 categories at 4 sites by the specialists.
• Using the same categories without guidelines after viewing speech and nasolaryngoscopy video recordings, 75 patients were independently classified by 4 international experts.
• From the 4 sites, each member also classified 50 patients from other sites after viewing video clips of voice/laryngeal tasks.
• Among rater pairs and across recruiting sites, interrater Κ less than 0.40 indicated poor classification agreement.
• Consequently, speech and laryngeal movement attributes were identified and ranked for classifying ADSD, ABSD, VT, and MTD, by a Delphi panel of 13 experts which were reviewed by 46 community specialists.
• For each disorder, a final attribute list was created based on the median attribute rankings.

Results

• Findings suggested that while classifying patients without guidelines, raters differed in their classification distributions (likelihood ratio, χ2=107.66), had poor interrater agreement, and poor agreement with site categories.
• The highest agreement was 34% for 11 categories, with no Κ values greater than 0.26.
• Results demonstrated that in external rater pairs, the highest Κ was 0.23 and the highest agreement was 38.5%.
• As per data, the highest percent agreement was 73.3% and the highest Κ was 0.40 using 6 categories.
• For classifying disorders from speech and nasolaryngoscopic examinations, 18 attributes were yielded by the Delphi method.