Stimulus Equivalence Learning in Acquired Brain Injury.

The Principle of Stimulus Equivalence Learning and Its Neuropsychological Correlates in Adults With Acquired Brain Injury (ABI).

Stimulus Equivalence Learning (SEL) is a form of learning in which stimuli (such as words, pictures, or sounds) become linked to one another in memory, even though this specific connection has not been directly taught. In a typical SEL task, two relations are taught explicitly (A→B and A→C), and the untrained relation (B→C) is then tested. This indirect relation is not intentionally or consciously learned and is considered a form of implicit learning. The principle of stimulus equivalence learning is still rarely applied in cognitive rehabilitation after acquired brain injury (ABI), with the exception of a few small (N=1) treatment studies that have shown positive effects. However, it remains unclear to what extent ABI may affect the ability to acquire stimulus equivalence.

Study Overview

• Status: Recruiting
• Conditions: Acquired Brain Injury (Including Stroke)

• Study Type: Observational
• Enrollment (Estimated): 40

Contacts and Locations

• Study Contact: Name: Edo Grevers, MSc.; Phone Number: +31620839323; Email: e.grevers@klimmendaal.nl

Study Locations

• Netherlands
  • Gelderland
    • Arnhem, Gelderland, Netherlands, 6813 GG
      • Recruiting
      • Klimmendaal Revalidatiespecialisten
      • Contact: Edo Grevers, MSc.; Phone Number: +31620839323; Email: e.grevers@klimmendaal.nl

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

• Sampling Method: Non-Probability Sample

Study Population

ABI patients (>3 months post-injury), including stroke, traumatic brain injury, brain tumor, encephalitis, and out-of-hospital cardiac arrest (OHCA).

Description

Inclusion Criteria:

ABI patients (>3 months post-injury), including stroke, traumatic brain injury, brain tumor, encephalitis, and out-of-hospital cardiac arrest (OHCA).

Exclusion Criteria:

Neurodegenerative disorders Severe psychiatric disorders (including suicidality) Insufficient command of the Dutch language Severe cognitive impairments, aphasia, or visual or hearing problems that make test administration impossible

An additional exclusion criterion for controls was any medical condition that could lead to cognitive impairment beyond normal aging, including stroke, TBI, brain tumor, or other forms of brain injury.

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort
healthy controls
acquired brain injury

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Modified Rutgers Equivalence Learning Task (mRAET)	The original RAET is an experimental paradigm in which faces have to be paired with colored fish. For the current study, this task has been adapted into a more ecologically valid version focused on medication intake, in which relationships are learned between the shape of a pill, the function of the pill, the time of intake, and the (fictional) brand name.	Day 1

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Location Learning Test (LLT)	The LLT is a test that can be used to measure episodic spatial memory for object locations. Normalized scores for immediate and delayed spatial memory are computed (percentiles 0-100).	Day 1
Wechsler Adult Intelligence Scale IV-NL digit span (WAIS-IV-NL DS)	The digit span is a measure of verbal working memory. Normalized standard scores can be computed (range 0-19, mean: 10, standard deviation: 3).	Day 1
Everyday memory questionnaire-revised (EMQ-R)	This is a 13-item scale of the everyday memory functioning.	Day 1
Trial Making Test	The Trail Making Test (TMT) is a neuropsychological test that measures processing speed, visual attention, and task switching.	Day 1
Stroop	The Stroop Test is a cognitive task that measures selective attention, processing speed, and the ability to inhibit automatic responses. Participants are shown color words printed in incongruent ink colors (e.g., the word "red" printed in blue ink) and must name the ink color rather than read the word. The interference effect-slower or less accurate responses-reflects challenges in cognitive control and response inhibition.	Day 1
Rey Auditory Verbal Learning Test (RAVLT)	The Rey Auditory Verbal Learning Test, RAVLT) is a verbal learning and memory task in which a list of 15 unrelated words is read aloud over several trials. The participant is asked to recall as many words as possible after each trial, and later again after a delay. The test assesses immediate recall, learning ability, retention, and recognition memory.	Day 1
Serial Reaction Time Task (SRTT)	Participants respond to the location of a black circle that appears in one of four screen positions by pressing the corresponding response key as quickly and accurately as possible. After 12 practice trials, the task consists of 8 blocks of 60 trials. Blocks 1-6 contain a fixed repeating sequence of locations (not disclosed to participants). Block 7 contains a different sequence, followed by a return to the original sequence in Block 8. After the task, participants complete questions assessing explicit awareness of the sequence. Implicit learning is indicated by faster reaction times in Blocks 6 and 8 (repeated sequence) compared to Block 7 (irregular sequence).	Day 1

Collaborators and Investigators

• Sponsor: Klimmendaal Revalidatiespecialisten
• Collaborators: Donders Centre for Cognitive Neuroimaging

Study record dates

Study Major Dates

• Study Start (Actual): January 29, 2026
• Primary Completion (Estimated): June 1, 2026
• Study Completion (Estimated): July 1, 2026

Study Registration Dates

• First Submitted: December 10, 2025
• First Submitted That Met QC Criteria: January 8, 2026
• First Posted (Actual): January 15, 2026

Study Record Updates

• Last Update Posted (Actual): May 22, 2026
• Last Update Submitted That Met QC Criteria: May 20, 2026
• Last Verified: January 1, 2026

More Information

Terms related to this study

• Keywords: acquired brain injury; implicit memory
• Additional Relevant MeSH Terms: Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Wounds and Injuries; Craniocerebral Trauma; Trauma, Nervous System; Brain Injuries
• Other Study ID Numbers: KNP23PROJ2

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No