Cog-VACCINE: Cognitive Training in Patients With Vascular Cognitive Impairment, no Dementia

Background:

Vascular cognitive impairment no dementia (VCIND) refers to cognitive deficits associated with underlying vascular causes which fall short of a dementia diagnosis. Because of its high prevalence and high progression to dementia, interest in VCIND has greatly expanded in recent years. Although it has been widely recognized that early intervention of VCIND holds the potential to delay or even reverse the cognitive impairment, no treatment is available yet. Executive dysfunction is the characteristic impairment in subcortical VCIND, and cognitive training significantly improved executive and other aspects of cognitive function in health older adults and patients with cognitive impairment. Whether and how cognitive training improves cognitive function in patients with VCIND remains largely unknown.

Objectives:

The primary objective of this double-blinded, randomized RCT is to assess whether internet-based cognitive training in patients with subcortical VCIND improves their cognitive abilities. The second objective is to evaluate the effect of cognitive training on neural plasticity, including brain activation and white matter integrity, which are assessed by functional and structural MRI. Finally, possible genetic and plasma biomarkers related to a positive effect or lack of effect of the training will be examined.

Patients and Methods:

The proposed study is a three-center, double-blinded, randomized controlled trial that will include 60 patients diagnosed with VCIND from the neurology clinics at Beijing Friendship hospital, Xuan Wu hospital, and geriatric clinic at Fu Xing hospital, Capital Medical University. The patients will be randomized to either a training or a control group. The intervention is internet-based cognitive training performed for 30 minutes over 35 sessions. Neuropsychological assessment and functional magnetic resonance imaging (MRI) will be performed before and 7 weeks after training.

Relevance:

Currently there is no known treatment available for VCIND. The proposed study is to determine the efficacy of cognitive training in patients with VCIND. Secondly, using functional and structural MRI, this study is to reveal the potential mechanism underlying cognitive training.

Inclusion criteria

• Literate Han Chinese, aged 50-78 years, with a consistent caregiver who accompanies the subject at least 4 days a week;
• Complaint and/or informant report of cognitive impairment involving memory and/or other cognitive domains lasting for at least 3 months;
• Neither normal nor demented according to the criteria of the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, with a clinical dementia rating (CDR) ≥ 0.5 on at least one domain and global score ≤ 0.5; a Mini-Mental State Examination (MMSE) score ≥ 20 (primary school) or ≥ 24 (junior school or above);
• Normal or slightly impaired activities of daily living as defined by a total score of ≤ 1.5 on the three functional CDR domains (home and hobbies, community affairs, and personal care).

The MRI entry criteria are as follows:

• Multiple (≥ 3) supratentorial subcortical small infarcts (3-20 mm in diameter), with/without white matter lesions (WML) of any degree; or moderate to severe WML (score ≥ 2 according to the Fazekas rating scale) with/without small infarct;
• Absence of cortical and watershed infarcts, hemorrhages, hydrocephalus, and WMLs with specific causes (e.g., multiple sclerosis);
• No hippocampal or entorhinal cortex atrophy (score 0 according to the medial temporal lobe atrophy scale of Scheltens).

Exclusion criteria

• severe aphasia, physical disabilities, or any other factor that may preclude completion of neuropsychological testing;
• disorders other than subcortical VCIND that may affect cognition;
• a Hamilton depression scale (HAMD) score >17 or schizophrenia;
• new strokes within 3 months before baseline;
• inherited or inflammatory small vessel disease;
• clinically significant gastrointestinal, renal, hepatic, respiratory, infectious, endocrine, or cardiovascular system disease;
• cancer, alcoholism, drug addiction;
• use of medications that may affect cognitive functioning, including tranquilizers, anti-anxiolytics, hypnotics, nootropics, and cholinomimetic agents;
• inability to undergo a brain MRI.