Perceptual Learning and Memory Consolidation in Adults With and Without LI



Status:Recruiting
Conditions:Cognitive Studies
Therapuetic Areas:Psychiatry / Psychology
Healthy:No
Age Range:18 - 24
Updated:10/4/2018
Start Date:September 27, 2018
End Date:July 2021
Contact:Frances S Earle, PhD
Email:fsearle@udel.edu
Phone:302 831 3878

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Perceptual Learning and Memory Consolidation in Adults With and Without Language Impairment

This study tests a memory-based account of atypical speech perception in adults with
language-based learning disability (also known as developmental language impairment [LI]).
One perspective regarding the its etiology considers impoverished speech sound
representations to be central to the linguistic symptoms observed in LI. This project
examines a potential abnormality in the process of building speech sound representations in
LI.

Previous work by the PI has found that sleep is important for learning speech sounds.
Furthermore, different measures of speech perception (identification and discrimination),
reveal distinct patterns of learning that are consistent with that of declarative and
procedural memory consolidation. A division of labor by declarative and procedural memory
systems in the building of speech representations may imply that problems with phonology may
stem from selective weaknesses in declarative or procedural memory in predictive ways.

The first project Aim is to identify the memory substrates of novel phonetic category
formation. In Experiment 1, the investigators will obtain behavioral measures of declarative,
procedural, and speech sound learning before and after post-training sleep in 40 typical
adults and 20 adults with LI. Among typical adults, a double dissociation is predicted in
which speech identification will be predicted by individual differences in declarative
memory, and speech discrimination will be predicted by individual differences in procedural
memory. Moreover, adults with LI are predicted to demonstrate consolidation deficits across
memory types.

The second project Aim is to identify the neural substrates of phonetic category formation.
In Experiment 2, the investigators will obtain functional magnetic resonance (fMRI)
recordings of 20 TD and 20 LI adults performing post-training identification and
discrimination tasks on a trained speech contrast before and after sleep. In typical adults,
a Time by Speech-task interaction is predicted. Speech identification will recruit episodic
(hippocampal) information on Day 1 relative to classic regions for phonological processing on
Day 2. Speech discrimination will result in a change in magnitude of activation from Days 1
and 2 in the left inferior frontal gyrus (IFG), reflecting an overnight decrease in effort.
LI (n=20) is predicted to demonstrate reduced overnight change in neural activation relative
to TD in both tasks.

The investigators will recruit 60 adults with typical language (TD) and 40 LI participants
through a variety of community and university related contacts. 40 TD adults and 20 LI
participants will be enrolled in Experiment 1. 20 TD adults and 20 LI participants will be
enrolled in Experiment 2.

Both experiments will take place over 3 Sessions.

During Session 1, the investigators will administer various measures in order to validate
study eligibility, classify participants into groups, and other measures in order to further
characterize our samples. To that end, participants will be administered a pure tone
audiometric screening, and complete an interview questionnaire asking for background
information such as handedness, language background, language and reading development, and
development of motor skills. Trained research personnel will then administer an approximately
2-hour testing battery that includes measures of nonverbal cognition, language ability,
reading ability, attention, executive function, and phonological processing. Participants
will also complete questionnaires to assess their habitual sleep quality, sleepiness, and
individual chronotpyes.

All testing will be completed by a student clinician, and will be supervised by a certified
speech-language pathologist. 100% of administrations will be re-scored by a trained student
for accuracy. To account for attrition and non-qualifiers, we anticipate enrolling/screening
up to 200 individuals in Session 1 in order to arrive at the enrollment targets for
Experiments 1 and 2.

In both experiments, Sessions 2 and 3 takes place on two consecutive days. Session 2 will
take place in the late evening, and Session 3 will take place in the morning. We have
intentionally chosen not to employ a wake-state (AM-PM) control. This is done in order to
limit the potential variability in the amount of English exposure between sessions.
Between-session sleep duration will be monitored with an Actigraph wGT3X-BT accelerometer
(Actigraph, corp) worn on the non-dominant wrist. Actigraphs will be set to collect data in
60-second epochs via a validated algorithm (Cain & Geremia,2011). This method of recording
sleep/wake activity has been independently validated to agree with lab polysomnography at 85%
accuracy (Slater et al.,2015).

Experiment 1: behavioral measures During Session 2, participants will complete the three
learning tasks, declarative learning, procedural learning, nonnative speech learning (in that
order), and immediate post-learning assessments. During Session 3, participants will be
re-assessed in nonnative speech learning, declarative learning, and procedural learning (in
that order).

- Declarative memory will be assessed using an object recognition task following
incidental encoding.

- A version of the Serial Reaction Time task will be used to measure procedural learning.

- Perceptual learning of speech will be measured through performance on identification and
discrimination tasks on the dental and retroflex contrast.

Experiment 2: neuroimaging measures During Session 2, participants will complete the
nonnative contrast training in the late evening. Then they will enter a magnetic resonance
imagine (MRI) scanner, where their blood oxygen-level dependent signals will be recorded
while they complete the post-training identification and discrimination assessments. The
participants will complete the same in-scanner assessments of the perception of the nonnative
contrast during Session 3.

Inclusion criteria:

- Monolingual speakers of American English

- History of:

- Typical gestation

- Sensory-motor development

- Typical hearing and vision

- Nonverbal cognition within normal limits

Exclusion criteria:

- Current diagnosis of ADHD

- Developmental dyslexia

- Rapid automatized naming deficits

- Neurological disorders

- Socio-emotional disorders
We found this trial at
1
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Newark, Delaware 19716
Phone: 302-831-3878
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Newark, DE
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