| dc.description.abstract | Aims:
The aim of this thesis was firstly, to prospectively examine cognitive function
in relation to epilepsy, with event-related potential (ERP) and neuropsychological
assessments, over a one year period. Secondly, to investigate whether
electrophysiological measures have some predictive value for behavioural outcomes.
Methods:
A methodology development study investigated optimal stimulus and
recording parameters for the mismatch negativity (MMN).
A prospective epilepsy study included investigation of a healthy control
group, groups of patients with: primary generalised seizures (PGS), focal with
secondary generalised seizures (FSG) or focal seizures (FS) and a chronic pain group
undergoing anti-epileptic drug (AED) therapy. Assessments were conducted over the
course of 12 months: at baseline (session 1), 6-months follow-up (session 2) and 12-
months follow-up (session 3). ERP measures included the MMN, P3b and P3a.
Neuropsychology measures were obtained using visual reaction time, spatial working
memory, planning, word list learning, perseverative function, story recall memory
and word list learning tests.
Cross-sectional analyses of data obtained at sessions 1 and 2 were carried out
to investigate group differences at the different time points. Longitudinal analyses
were carried out to investigate the effect of time on behavioural and ERP changes in
relation to the different groups. Finally, the predictive value of baseline ERPs for
behavioural outcomes at one year follow-up was explored.
Results:
The methodology development study demonstrated that a reading task with
duration increment tones yielded the most replicable MMNs in healthy controls.
The clinical study demonstrated significant changes in some ERP
components obtained from standard oddball, dual target oddball and novel sounds
tasks, between controls and seizure groups -some of which were only apparent at
session 3. Although the seizure groups showed evidence of significant impairments
in aspects of behavioural performance, there was no significant progressive
deterioration over time. Moreover, although the pain group showed similar
behavioural impairments, in contrast to the seizure groups, they showed significant
improvements in some aspects of performance over time.
Conclusion: An MMN recording protocol was established for use with the
subsequent prospective clinical study. The prospective epilepsy study revealed
functional cognitive changes that may be linked to the nature of pathophysiology
underlying different seizure types. | en_US |
