Transient ischemic attack (TIA) is clinically defined as a self-limiting neurological event with full functional recovery within 24 hours. However, new evidence indicates that as many as 68% of TIA sufferers show subtle, sustained cognitive impairment that can have direct consequences for daily living. Patient-reported symptoms, such as mental fatigue, anxiety/depression, and difficulty returning to work, point to specific impairment of cognitive control. 

Cognitive control (aka executive functioning) refers to processes that allow us to coordinate daily activities in a coherent and goal-directed manner, e.g., to execute the steps required to plan, shop for and cook a meal. These abilities are critical for re-integration into daily life after neurological events such as TIA. 

Cognitive assessment is not a standard part of clinical assessment post-TIA. When cognition is assessed, it typically involves broad cognitive screening tools that are not domain-sensitive, such as the Montreal Cognitive Assessment (MoCA). These tests may indicate that the patient is performing lower than expected, but cannot pinpoint specific areas of cognitive decline (e.g., attention, planning). Therefore, they cannot guide personalised rehabilitation program delivery. 

Comprehensive neuropsychological assessments are more sensitive to specific cognitive domains. However, they are very labour-intensive and still not sensitive to the subtle cognitive changes that arise from disruption of crucial frontal brain networks – the networks that enable cognitive control. 

Frontal networks propagate information between anterior and posterior brain areas and support the dynamic and flexible integration of information across multiple sensory and motor domains. Disruption of frontal networks can result in subtle cognitive decline that impedes complex goal-directed behaviours, even in patients who appear to have recovered clinically. For instance, patients with frontal lobe damage may be able to follow instructions to turn off the stove but be unable to spontaneously initiate this action in response to an overflowing casserole.

Novel electroencephalography (EEG) analyses offer a promising solution. EEG is a sensitive, fast and affordable measure of brain activity. In young adults, we have developed a novel EEG assessment of frontal network functioning using a simple computer-based task. By combining EEG with brain imaging, we are designing approaches to link behaviour with frontal network functioning (EEG) and structure (MRI). 

We are seeking pilot funding to extend this network profile approach to characterise subtle changes in frontal network function post-TIA and how this relates to cognitive ability and quality of life measures. The ultimate aim is to develop a protocol that can be applied as part of standard clinical assessment to identify individuals who can benefit from cognitive rehabilitation, monitor cognitive profile over time, and inform decisions regarding return to work, driving, etc. Ultimately, we aim to develop EEG measures that can readily assess an individual’s cognitive control capacity using mobile EEG testing in the clinic or even at home. However, before these measures can be implemented clinically, we need to establish protocols for clinical use, test sensitivity and specificity, and develop guidelines for clinical testing.

Researchers 

A/Prof Frini Karayanidis, Dr Patrick Cooper, Dr Aaron Wong, Dr Andrew Bivard, Prof Chris Levi

Research Area 
Project type 
Project Grant
Year of funding 
2017