Investigating Speech Sequencing in Neurotypical Speakers and Persons With Disordered Speech

Boston University Charles River Campus

Status: Enrolling

Conditions: Aphasia, Primary Progressive; Stuttering, Developmental

Treatments: Behavioral: Learning of non-native phoneme combinations: 6 training sessions; Behavioral: Learning of non-native phoneme combinations: 8 training sessions; Device: Anodal tDCS; Device: Sham tDCS; Behavioral: Learning of novel multisyllabic nonwords; Behavioral: Learning of non-native phoneme combinations: 1 training session

Study type: Interventional

Funder types: Other; NIH

Identifiers

NCT05437159

R01DC007683

2R01DC007683-16A1 (U.S. NIH Grant/Contract)

1F31DC020352-01A1 (U.S. NIH Grant/Contract)

Details and patient eligibility

About

Persistent developmental stuttering affects more than three million people in the United States, and it can have profound adverse effects on quality of life. Despite its prevalence and negative impact, stuttering has resisted explanation and effective treatment, due in large part to a poor understanding of the neural processing impairments underlying the disorder. The overall goal of this study is to improve understanding of the brain mechanisms involved in speech motor planning and how these are disrupted in neurogenic speech disorders, like stuttering. The investigators will do this through an integrated combination of experiments that involve speech production, functional MRI, and non-invasive brain stimulation. The study is designed to test hypotheses regarding the brain processes involved in learning and initiating new speech sound sequences and how those processes compare in persons with persistent developmental stuttering and those with typical speech development. These processes will be studied in both adults and children. Additionally, these processes will be investigated in patients with neurodegenerative speech disorders (primary progressive aphasia) to further inform the investigators understanding of the neural mechanisms that support speech motor sequence learning. Together these experiments will result in an improved account of the brain mechanisms underlying speech production in fluent speakers and individuals who stutter, thereby paving the way for the development of new therapies and technologies for addressing this disorder.

Enrollment: 2 estimated patients

Sex: All

Ages: 6+ years old

Volunteers: Accepts Healthy Volunteers

Inclusion and exclusion criteria

Inclusion Criteria

• Healthy individuals with no history of neurological, speech, or hearing disorders (other than stuttering in studies that involve adults who stutter).
• To maximize the uniformity of prior exposure to the speech stimuli that will be used, only native speakers of American English will be recruited, and only those with limited exposure to a second language will be enrolled.
• All adult participants will also pass a standard pure-tone hearing screening at a 25dB hearing level threshold at 500, 1k, 2k, and 4kHz frequencies.
• All participating children will pass a hearing screening at a 20 dB threshold at 500, 1k, 2k, and 4k Hz.
• Participants in experiments that require them to read orthographic stimuli must have normal or corrected-to-normal vision (MRI-safe corrective glasses are available at the Boston University Cognitive Neuroimaging Center for use during neuroimaging).
• Participating children will complete additional speech, language, hearing, and cognitive tests to ensure that they are within normal performance ranges for their age with the exception of stuttering for children in the children who stutter (CWS) group.
• Persons who stutter will be evaluated formally by a speech-language pathologist to assess stuttering severity and to ensure the absence of other speech or language disorders. PWS will have no history of neurological disorder other than stuttering, and will demonstrate very mild to severe stuttering according to the Stuttering Severity Instrument for Children and Adults - 4th Edition (SSI-4: PRO-ED, Inc.), that is confirmed by clinical reports and expressed concern by the subject and/or guardian.
• Participants with primary progressive aphasia (PPA) will have been diagnosed through the Massachusetts General Hospital Frontotemporal Disorders Unit (MGH-FTD) by an experienced neurologist in coordination with a speech-language pathologist.
• Participants with PPA will have a score of 1.0 or lower on the Clinical Dementia Rating scale (i.e., mild cognitive impairment or mild dementia) to ensure cognitive levels are sufficient to complete the task.
• All participants with PPA must have a recent clinical assessment and T1 structural neuroimaging scan through the MGH-FTD Unit for eligibility for this study.

Exclusion Criteria

• Participants in studies that involve tDCS or MRI scanning will have no contraindications specific to those procedures. For the tDCS study, this includes individuals who have a metallic implant in the head or electrically sensitive devices implanted in the body, a history of seizures, significant scalp lesions, or pregnancy.
• For MRI studies, this includes a history of seizures, severe claustrophobia, the presence of magnetically or mechanically active implant, ferromagnetic material embedded in any part of the body, or pregnancy).
• All participants will perform a standardized nonword repetition pre-test (the Dollaghan and Campbell Nonword Repetition Task) to assess working memory performance. Participants who perform more than 2 standard deviations below the norm for their age range will be deemed to be unable to perform the experimental task and released from further participation.
• Participating children will have no history of neurological disorder other than stuttering, and will demonstrate very mild to severe stuttering according to the Stuttering Severity Instrument for Children and Adults, 4th Edition, that is confirmed by clinical reports and expressed concern by the subject and/or guardian.
• Children under the age of 6 and over the age of 8 will not enrolled in this study.
• Participants with PPA will not be eligible for this study if they are taking any medications that would be expected to affect speech or language.

Trial design

Primary purpose: Basic Science

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: None (Open label)

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2 participants in 7 patient groups

Sub-syllabic learning and fMRI

Experimental group

Description:

60 adults with neurotypical speech development will participate in this arm. Subjects will learn novel 1-syllable nonsense words formed by non-native phoneme combinations during 6 training sessions over 2 days. Following training, subjects will participate in a functional magnetic resonance imaging (fMRI) session on a third day to measure brain activity associated with producing the words learned during training and with a set of unfamiliar words also formed by non-native phoneme combinations.

Treatment:

Behavioral: Learning of non-native phoneme combinations: 6 training sessions

Sub-syllabic learning and anodal tDCS of inferior frontal sulcus

Experimental group

Description:

35 adults with neurotypical speech development will participate in this arm. Subjects will learn novel 1-syllable nonsense words formed by non-native phoneme combinations. During the training, anodal transcranial direct current stimulation (tDCS) will be applied to the the subject's left inferior frontal sulcus.

Treatment:

Behavioral: Learning of non-native phoneme combinations: 1 training session

Device: Anodal tDCS

Sub-syllabic learning and anodal tDCS of cerebellum

Experimental group

Description:

35 adults with neurotypical speech development will participate in this arm. Subjects will learn novel 1-syllable words formed by non-native phoneme combinations. During the training, continuous anodal transcranial direct current stimulation (tDCS) will be applied to the the subject's right cerebellum.

Treatment:

Behavioral: Learning of non-native phoneme combinations: 1 training session

Device: Anodal tDCS

Sub-syllabic learning and sham tDCS

Sham Comparator group

Description:

35 adults with neurotypical speech development will participate in this arm. Subjects will learn novel 1-syllable words formed by non-native phoneme combinations. During training, Sham transcranial direct current stimulation stimulation (tDCS) will be delivered to the subject's brain.

Treatment:

Behavioral: Learning of non-native phoneme combinations: 1 training session

Device: Sham tDCS

Multisyllabic learning and fMRI in adults

Experimental group

Description:

30 adults persistent developmental stuttering (AWS) and 30 adults with neurotypical speech development (ANS) will participate in this arm. Subjects will learn nonsense words formed by novel combinations of 3 syllables that are legal in American English during 6 training sessions over 2 days. Following training, subjects will participate in a functional magnetic resonance imaging (fMRI) session on a third day to measure brain activity associated with producing the words formed by pairing 2 learned 3-syllable strings learned during training and those formed by pairing 2 unfamiliar 3-syllable strings. Behavioral measures extracted from the data will be used to compare performance before and after training and across the AWS and ANS participants.

Treatment:

Behavioral: Learning of novel multisyllabic nonwords

Multisyllabic learning in children

Experimental group

Description:

45 children with persistent developmental stuttering (CWS) and 45 children with neurotypical speech development (CNS) will participate in this arm. Subjects will learn nonsense words formed by novel combinations of 2 syllables that are legal in American English during 6 training sessions over 2 days. Behavioral measures extracted from the data will be used to compare performance before and after training and across the CWS and CNS participants.

Treatment:

Behavioral: Learning of novel multisyllabic nonwords

Sub-syllabic learning in PPA

Experimental group

Description:

30 adults with primary progressive aphasia (PPA) will participate in this arm. Subjects will learn novel 1-syllable nonsense words formed by non-native phoneme combinations during 8 training sessions over 2 days. Following training, subjects will complete a behavioral test to compare their performance on the words learned during training with a set of unfamiliar words also formed by non-native phoneme combinations.

Treatment:

Behavioral: Learning of non-native phoneme combinations: 8 training sessions