Moderators and Mediators of Perceptual Learning

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

• Ages 18 to 85 years
• All sexes
• Healthy volunteers accepted
• Adult, Older adult

Trial locations and contacts

3 sites in 1 country. Contact the study team or a site near you to ask about taking part.

About this study

Conditions

Cognitive Change

Being tested

C1 - Standard Perceptual Learning (SPL), C2 - Long Training (LT), C3 - Short Staircases (SS), C4 - Mixed Difficulty (MD), C5 - Noise Training (NT)

Keywords

Vision Training

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

• C1 - Standard Perceptual Learning (SPL)Behavioural

  Each trial starts with a fixation point (500ms) after which a Gabor (1° radius, at cut-off SF of 25% accuracy, estimated from Pre-Test CSF, at either 45° or 135°) appears for 128ms. The task is to indicate whether the Gabor was tilted left or right. Gabor contrast will be controlled by a 3/1 staircase (converging on approximately ~80% contrast threshold) across all training sessions.

• C2 - Long Training (LT)Behavioural

  Will be the same as the SPL with the exception that each session in LT will be twice as long as in SPL.

• C3 - Short Staircases (SS)Behavioural

  Will be largely the same as SPL with the only difference being a change to the adaptive procedure. SS will use so-called "short-staircases," which are initialized at 60% contrast with steps of .05 log units and employs a 3/1 staircase that after every 40 trials is reset (the "short" in "short-staircases") back to 60% contrast.

• C4 - Mixed Difficulty (MD)Behavioural

  This condition will be identical to SPL with the exception that two staircases - one a 2/1 staircase producing difficulties centered around 60-70% accuracy, the other a 4/1 staircase producing difficulties centered around 85-95% accuracy - will be utilized to control the stimuli.

• C5 - Noise Training (NT)Behavioural

  The NT condition will be the same as SPL with the exception that contrast thresholds will be estimated in 5-different levels of external noise (10%, 15%, 20%, 25%, 30%).

• C6 - Training with Flankers (TWF)Behavioural

  TWF will be reasonably different from the standard SPL task. Here, on 50% of trials a target Gabor will be presented at either 45° or 135° (as in SPL) and will be flanked by two collinear Gabors. On the remaining 50% of trials, flankers will be present without a target. TWF is thus a yes/no detection task, which is necessary since the collinear flankers fully indicate the target orientation. In different 20-trial mini-blocks the flankers will appear either lambda, 1.5 lambda, or 2 lambda from the target (i.e., closer or further from the target) and target contrast will be controlled by a 3/1 staircase separately for each spacing.

• C7 - Parafoveal Training (PT)Behavioural

  The PT condition is the baseline for C8-C11 (all of which involve parafoveally presented targets). In PT, we utilize the same task as in SPL, however, in PT, in addition to central training, targets will also appear in one of two peripheral locations (5° eccentricity; angles = 135° and 270°). The location of targets will be randomized trial-wise so as to discourage eye-movements and independent 3/1 staircases will be run at each location. By training only 2 peripheral locations we can measure the extent to which training gives rise to location transfer (e.g., in transfer tasks examining performance at 8 different locations - 2 trained locations and 6 untrained locations). Furthermore, training at the central location facilitates comparisons between PT and SPL.

• C8 - Stimulus Variety (SV)Behavioural

  The base task for SV is the PT condition. However, SV employ 20 trial mini-blocks of different SFs (.75, 1.5, 3, 6, 12, 24 cpd) and locations (45°, 135°, 225°, 315° - i.e., more locations than PT, but not the full set tested in the transfer battery) with separate staircases for each SF and location. Orientations will also be drawn from a larger set (22.5°, 45°, 67.5° - for which participants respond "clockwise" and 112.5°, 135°, 157.5° - for which participants respond "counter-clockwise") and will vary on a trial-by-trial basis. This design holds-out 4 locations and 2 orientations to address transfer.

• C8a - Complex Features (CF)Behavioural

  This is the same as C8, however we will use band-pass filtered stimuli similar to what has been done by a number of groups including Hussein et al.

• C9 - Exogenous Attention Training (ExAT)Behavioural

  Stimuli will be presented in a similar manner as in PT. However, in ExAT, a 100% valid cue, a small black dot - 48ms duration with an 96ms SOA prior to stimulus onset - will appear above the target location on each trial.

• C10 - Endogenous Attention Training (EnAT)Behavioural

  Stimuli will be presented in a similar manner as in PT. However, in EnAT, a 100% valid cue (letter UL, LR; standing for upper left and lower right, respectively) - 150ms duration with an 500ms SOA prior to stimulus onset - will appear at the fixation point.

• C11 - Multisensory Facilitation (MF)Behavioural

  MF utilizes the same basic task structure as in ExEAT, however, rather than a visual cue, an auditory cue will be used (50ms, 1000hz tone with sound location determined by convolving sound with generic head-related transfer function, kemar large ears.

• No Contact ControlBehavioural

  While not a "training condition" one type of experience that could be part of a condition is a no contact control (i.e., where participants do no training activities over the same rough time span as for the other training tasks).

What is being measured

The primary outcome is the main question the study is designed to answer.

1. Change in Near Transfer Task

   We will utilize an overarching task structure that allows us to assess learning on trained stimuli and transfer to untrained stimuli; locations, orientations, stimulus timings (e.g., we will assess contrast sensitivity for 6 different orientations). A trial begins with a fixation-point presented for 500ms. A target stimulus then appears for 128ms and then disappears (this timing was chosen to preclude participants making eye-movements to the stimuli). The participant is then required to respond by indicating the orientation of the stimulus (e.g., the major axis of a Gabor stimulus or gap-side of a C stimulus). In contrast tests, a staircase is run on the contrast of the target stimulus. In acuity tests, a staircase is run on the size of the stimulus. In parafoveal tests, stimuli are presented at 5° eccentricity.

   Measured: Baseline to Post-test 2, an average of 5-8 weeks

2. Change in Transfer to Visual Search

   In a T/L annular visual-search task (1° stimuli, presented at 5° eccentricity at each of 8 evenly spaced locations), on each trial, 7 positions are filled with a distractor (upside-down Ls, half black and half white), while 1 position contains a target (rightside-up T that is either white or black). Stimuli are presented for 256ms and, after a variable SOA, a stimulus-mask (asterixis) appears. Participants report the color of the T. A 3/1 staircase controls the SOA of the mask (shorter SOAs = less time between stimulus and mask = more difficult). This task tests how training impacts processing time (i.e., time necessary to find and identify targets). Also, given that the same locations are used as in the parafoveal training, we can also estimate the extent to which transfer to visual search occurs and, if so, whether it is specific to the trained location.

   Measured: Baseline to Post-test 2, an average of 5-8 weeks

3. Change in Transfer to Reading

   To understand visual performance related to reading, we employ the MNRead task, where participants read short sentences out-loud at various font-sizes. Dependent variables include reading speed, minimal text-size (another measure of acuity), and also critical print-size (text-size at which reading speed slows down).

   Measured: Baseline to Post-test 2, an average of 5-8 weeks

4. Change in Transfer to Auditory Attention

   The procedure is based upon a speaker-on-speaker task where participants choose between 36 call signs (a color and number) spoken by a speaker. This task measures auditory thresholds for speech in the presence of other talkers, when all talkers are spatially collocated compared to when they are spatially offset.

   Measured: Baseline to Post-test 2, an average of 5-8 weeks

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

1. First posted8 Jun 2023
2. Study start14 Apr 2023
3. Primary completion28 Feb 2027 (estimated)
4. Study completion31 Mar 2027 (estimated)

Resources

• Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
• Other trials for Cognitive ChangeStudies of the same condition, open and under way.
• What the trial phases meanHow a treatment moves from first tests in people to approval.

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.