The goal of this clinical trial is to learn about the effect of communicative interaction on verbal communication in people with amyotrophic lateral sclerosis (ALS) and age-matched speakers.

The question is, What are the effects of communicative interaction on verbal communication in people with ALS?

Participants will read words and sentences while they are in a solo setting and interactive setting.

PALS and age-matched adults will participate in one solo speech production task (clear speech) and three interactive tasks (structured communicative interaction, unstructured communicative interaction, and clear speech structured communicative interaction) in which they work with an unfamiliar, naive interlocutor. This study is designed to examine the differences in speech produced in the four tasks. Comparisons of speech produced by PALS and age-matched adults will clarify whether differences in speech observed across the four tasks are a function of the speech difficulties experiences by PALS.

Plans for Assignment - This is a single group study in which all participants will engage in the same tasks.

Delivery of Intervention: Using tablets and audio recording devices provided to them, participants will complete this task in the comfort of their home. Study protocols will be explained via videoconferencing by experimenters. Produced speech will be recorded using solid-state audio recorders as well as remotely through the video conferencing software.

Adequacy of Sample size. Assuming medium effect sizes (Cohen's f = 0.3) based on our pilot data, for 80% power at an alpha of .05, the investigators will require 76 speakers. The investigators propose n = 100 PALS in order to account for speech variability that is common for PALS. The investigators plan to recruit 50 age-matched speakers. The investigators anticipate that this sample size will be sufficient to make appropriate comparison to the PALS group because there will be considerably less variability in these speakers.

Adequacy of Analyses. The proposed statistical analyses (Generalized mixed effects regressions) are standard and will be used to analyze the effect of the intervention on the outcome measures described below. Severity of condition (for PALS) will be included in the analyses and by-subject slopes and intercepts will be used to account for variability across participants.

Inclusion Criteria:

Speakers with amyotrophic lateral sclerosis (ALS) (PALS-people with ALS)

• diagnosis of ALS following the revised EL Escorial criteria
• no history of other neurological conditions (e.g., stroke)
• no cognitive impairment assessed by Telephone Montreal Cognitive Assessment (mini MoCA)
• detectable speech disturbance according to the ALS Functional Rating Scale-Revised (ALSFRS-R)
• the ability to produce single words
• being a native speaker of American English (AE).

Age-matched Speakers

• passing the remote hearing screening
• having no known speech, language, or neurological disorders per self-report
• no cognitive impairment assessed by Telephone Montreal Cognitive Assessment (mini MoCA)
• being a functionally native monolingual speaker of American English.

Unfamiliar Interlocutors

• passing the remote hearing screening
• having no known speech, language or neurological disorders per self-report
• being a native monolingual speaker of American English
• having no experience communicating with people with dysarthria
• being between the ages of 18 and 40.

Exclusion Criteria:

• None - if volunteer meets the inclusion criteria, then they will be enrolled

The project will involve the collection of audio samples, perceptual judgments, and questionnaire data. All deidentified data will be shared through the Open Science Framework (osf.io). All scripts, protocols, procedures, and analyses will be shared along with the deidentified data to ensure that other researchers can verify and build on the presented results. All shared data will be made available in a format that is accessible by open-access software (e.g., R, Open Office, pdf reader). In addition, platform-specific scripts (e.g., experimental software LabVanced) will be shared with explanations so that they may be implemented across different software environments.

Data will be shared after publication of the study.

All deidentified data, metadata, and related tools will be freely available via Open Science Framework (OSF). The original audio files will be made available (for participants who consent) by request from researchers in the field to ensure responsible use.