Reliability of Phonemically Loaded Sentences in Spanish for Identifying Laryngeal Dystonia by Non-Spanish Speaking Speech-Language Pathologists

Abstract

Laryngeal dystonia (LD) is a focal dystonia affecting the intrinsic laryngeal muscles. Clinical diagnosis requires subjective evaluation by experienced clinicians and is primarily based on auditory-perceptual assessment. Several speech tasks are widely accepted to elicit diagnosis specific auditory-perceptual symptoms of glottal stops in adductor LD or breathy breaks in abductor LD in spoken English. With the growing Spanish speaking population in the US and lack of Spanish speech tasks to assist in identifying LD in Spanish speaking subjects, assessing the reliability of phonemically loaded sentences in Spanish for use by non-Spanish speaking providers is critical. The first aim of this study was to develop and assess the reliability of a set of Spanish language phonemically loaded sentences designed to elicit signs and symptoms of LD. The second aim was to determine the effectiveness of non-Spanish speaking speech-language pathologists (SLPs) in identifying LD in Spanish speaking subjects using these stimuli. Phonemically loaded sentences were developed for this study following current guidelines for assessment of LD. Voice samples were obtained from native Spanish speaking individuals. Participant-speakers included 20 people with LD and 20 people without LD who served as controls. All participant-speakers were assessed by a Spanish-speaking laryngologist. Audio samples were presented to non-Spanish speaking SLPs with expertise in working with people with LD who served as raters and classified the samples as either presence or absence of LD. Kappa and the intra-class correlation coefficient were calculated and mixed effects logistic regression was used for prediction. The inter and intra-rater reliability indicated statistically significant agreement. Sensitivity, specificity, and predictive values for the diagnosis of LD by the raters were overall strong. Findings demonstrate that non-Spanish speaking SLPs with expertise in the assessment and treatment of LD can reliably identify the presence of LD using Spanish language stimuli in Spanish-speaking individuals. This study supports the use of newly developed Spanish language phonemically loaded voiced and voiceless sentences by English speaking clinicians as an effective tool for identifying LD in Spanish speakers, perhaps mitigating diagnostic delays experienced by patients with LD.