Haned Akhlaghi - Experimental Neuropsychology Research Unit

Cognitive compensatory mechanisms in cerebellar vs. spinocerebellar ataxia using functional magnetic resonance imaging

Main Supervisors: A/Prof Gary Egan (Howard Florey Institute), A/Prof Nellie Georgiou-Karistianis (Monash University), A/Prof Martin Delatycki (Murdock Children's research Institute).

Traditionally, the cerebellum has been thought to coordinate voluntary movement. Recent studies however have implicated the cerebellum in a range of cognitive functions including executive function, visuo-spatial organisation and memory. Friedreich's ataxia (FRDA) is the most common genetic cause of ataxia and is widely held to predominantly affect the spinal cord, peripheral sensory nerves and cerebellum. More recent studies however have shown more widespread degeneration in a range of brain areas, thus explaining some of the cognitive deficits observed in FRDA. This is of potential significance since cognitive deficits are a potential source of significant morbidity.

We will use a well validated cognitive task to compare the patterns of cerebral functional activation in the ataxias via the use of functional magnetic resonance imaging (fMRI). We shall use these methods to dissociate cognitive differences between the ataxias and their correlates with simple and complex motor measures. We will also document the degree of disease progression in a longitudinal design by comparing performance on tasks and imaging data once a year for three years.

A fundamental component of this research is to develop validated, objective outcome measures to document more reliably clinical severity of disease and progression. This will lead to an understanding of how each disease is expressed, as well as the mechanisms underlying such expression. The design of appropriate therapeutic and rehabilitative interventions in future is greatly dependent on a complete understanding of not only the motor dysfunction but also the underlying cognitive impairment associated with these conditions.