The purpose of this study is to find out whether pairing vagus nerve stimulation (VNS) with cognitive training can improve memory and language learning in people who have previously used VNS therapy for movement rehabilitation after a stroke. VNS has been previously used to support motor recovery after stroke, but its effect on cognitive learning is not yet fully understood. This study is enrolling individuals who already have a VNS device implanted and have successfully completed VNS-assisted movement therapy. The investigators aim to explore whether continuing to use the device during a language learning program may also support memory and cognitive improvement. This is a research study, which means the use of VNS for cognitive enhancement is experimental and not currently part of standard treatment. An exploratory MRI/fMRI component also will assess whether VNS-paired language learning is associated with changes in task-based activation and resting-state functional connectivity in language, memory, salience/arousal, and frontoparietal cognitive-control networks. The information learned may help guide future approaches to stroke rehabilitation and cognitive recovery.
Stroke survivors frequently experience persistent cognitive, memory, and language-related difficulties that can affect independence and quality of life. VNS paired with rehabilitation has been shown to enhance motor recovery after stroke, and paired stimulation may support experience-dependent neural plasticity. This study extends that approach to cognitive and language learning by pairing VNS with structured foreign-language vocabulary training. Eligible participants will be adults with prior stroke who are scheduled to receive, or have received, clinically indicated Vivistim VNS implantation for rehabilitation and who are able to participate in the language-learning intervention. Participants will be randomized to active VNS or sham stimulation during daily language-learning sessions over approximately six weeks. The active stimulation group will receive programmed VNS paired with language-learning stimuli; the sham group will undergo the same language-learning procedures with stimulation amplitude set to zero or otherwise configured according to the sham protocol. Participants will be blinded to group assignment when feasible. The neuroimaging sub-study will include MRI/fMRI at up to three time points: pre-surgery baseline, when feasible before clinically indicated implantation; post-surgery/pre-language-training baseline; and post-training. The post-surgery/pre-training scan is the key baseline for the language-learning intervention, particularly for participants who already have the device implanted. MRI sessions will include structural MRI, resting-state fMRI, and a task-based foreign-word semantic matching paradigm. The primary task-based fMRI contrast will examine changes in neural responses to future-trained versus trained foreign words compared with never-trained foreign words. Resting-state analyses will examine changes in functional connectivity across language, memory, salience/arousal, frontoparietal cognitive control, and stroke recovery networks. A brief optional 0-back/1-back working-memory fMRI task may be included if scan time and participant tolerance allow.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
SINGLE
Enrollment
20
Subjects previously implanted with VNS will undergo second language acquisition
Stony Brook University Hospital
Stony Brook, New York, United States
Change in Foreign-Language Vocabulary Learning Accuracy
Vocabulary learning will be assessed using trained foreign-language vocabulary items. The outcome is the percentage of trained vocabulary items correctly recalled, recognized, or translated. Scores range from 0% to 100%, with higher scores indicating better vocabulary learning.
Time frame: Baseline and 6 weeks
Change in Foreign-Language Sentence Learning Accuracy
Sentence learning will be assessed using trained short foreign-language sentences. The outcome is the percentage of trained sentence items correctly understood, completed, recalled, or translated. Scores range from 0% to 100%, with higher scores indicating better sentence learning.
Time frame: Baseline and 6 weeks
Change in Global Cognition on the Montreal Cognitive Assessment (MoCA)
Global cognition will be measured using the Montreal Cognitive Assessment total score. Scores range from 0 to 30, with higher scores indicating better cognitive function.
Time frame: 6 weeks
Change in Verbal Learning on the Rey Auditory Verbal Learning Test
Verbal learning will be measured as the total number of words recalled across Rey Auditory Verbal Learning Test learning trials. Scores range from 0 to 75, with higher scores indicating better verbal learning.
Time frame: 6 weeks
Change in Delayed Verbal Memory on the Rey Auditory Verbal Learning Test
Delayed verbal memory will be measured as the number of words recalled after a delay on the Rey Auditory Verbal Learning Test. Scores range from 0 to 15, with higher scores indicating better delayed verbal memory.
Time frame: 6 weeks
Change in Verbal Learning on the Hopkins Verbal Learning Test-Revised
Verbal learning will be measured as the total number of words recalled across Hopkins Verbal Learning Test-Revised immediate recall trials. Scores range from 0 to 36, with higher scores indicating better verbal learning.
Time frame: 6 weeks
Change in Delayed Verbal Memory on the Hopkins Verbal Learning Test-Revised
Delayed verbal memory will be measured as the number of words recalled after a delay on the Hopkins Verbal Learning Test-Revised. Scores range from 0 to 12, with higher scores indicating better delayed verbal memory.
Time frame: 6 weeks
Change in Language Function on the Western Aphasia Battery
Language function will be measured using the Western Aphasia Battery Aphasia Quotient. Scores range from 0 to 100, with higher scores indicating better language function.
Time frame: 6 weeks
Change in Story Recall on the Automatic Story Recall Test
Story recall will be measured using the Automatic Story Recall Test score. Scores will be reported as the percentage of story content correctly recalled, ranging from 0% to 100%, with higher scores indicating better story recall.
Time frame: 6 weeks
Change in Working Memory on the Digit Span Task
Working memory will be measured using the Digit Span Task total raw score. Scores range from 0 to 48 if using the WAIS-IV Digit Span version, with higher scores indicating better working memory.
Time frame: 6 weeks
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