Cohort study ON Neuroimaging, Etiology and Cognitive consequences of Transient neurological attacks (CONNECT): study rationale and protocol

Transient ischemic attacks (TIA) are characterized by acute onset focal neurological symptoms and complete recovery within 24 hours. Attacks of nonfocal symptoms not fulfilling the criteria for TIA but lacking a clear alternative diagnosis are called transient neurological attacks (TNA). Although TIA symptoms are transient in nature, cognitive complaints may persist. In particular, attacks consisting of both focal and nonfocal symptoms (mixed TNA) have been found to be associated with an increased risk of dementia. We aim to study the prevalence, etiology and risk factors of cognitive impairment after TIA or TNA.

CONNECT is a prospective cohort study on cognitive function after TIA and TNA. In total, 150 patients aged ≥45 years with a recent (<7 days after onset) TIA or TNA and no history of stroke or dementia will be included. We will classify events as: TIA, nonfocal TNA, or mixed TNA. Known short lasting paroxysmal neurological disorders like migraine aura, seizures and Ménière disease are excluded from the diagnosis of TNA. Patients will complete a comprehensive neuropsychological assessment and undergo MRI <7 days after the qualifying event and again after six months. The primary clinical outcomes will be cognitive function at baseline and six months after the primary event. Imaging outcomes include the prevalence and evolution of DWI lesions, white matter hyperintensities and lacunes, as well as resting state networks functionality and white matter microstructural integrity. Differences between types of event and DWI, as well as determinants of both clinical and imaging outcomes, will be assessed.

CONNECT can provide insight in the prevalence, etiology and risk factors of cognitive impairment after TIA and TNA and thereby potentially identify a new group of patients at increased risk of cognitive impairment.