TY - JOUR
T1 - Ocular motor measures of cognitive dysfunction in multiple sclerosis II
T2 - working memory
AU - Clough, Meaghan
AU - Mitchell, Laura
AU - Millist, Lynette
AU - Lizak, Nathaniel
AU - Beh, Shin C
AU - Frohman, Teresa C.
AU - Frohman, Elliot
AU - White, Owen B.
AU - Fielding, Joanne
N1 - Funding Information:
We would like to thank all the participants who gave up their time and conscientiously completed each task. We would also like to thank Bayer, Australia for providing the financial support for this study. The authors are deeply grateful to Mr. Jason Thean Kit Ooi, for his patience, dedication, perseverance, and hard work on the creation of the medical illustrations contained within this two-part series on cognitive abnormalities in MS.
Publisher Copyright:
© 2015, Springer-Verlag Berlin Heidelberg.
PY - 2015/5/26
Y1 - 2015/5/26
N2 - Our companion paper documents pervasive inhibitory deficits in multiple sclerosis (MS) using ocular motor (OM) measures. Here we investigated the utility of an OM working memory (WMem) task in characterising WMem deficits in these patients as a function of disease status and disease duration. 22 patients with CIS, 22 early clinically definite MS patients (CDMS: <7 years of diagnosis), 22 late CDMS patients (>7 years from diagnosis), and 22 healthy controls participated. All participants completed the ocular motor WMem task, the paced auditory serial addition test (PASAT), and the symbol digit modalities test (SDMT). Clinical disability was characterised in CDMS patients using the Expanded Disability Severity Scale (EDSS). WMem performance was measured as proportion of errors (WMem errors), saccade latency, and relative sensitivity to WMem loading (WMem effect), an indicator of WMem capacity. All patient groups performed more WMem errors than controls with proportion of WMem errors, and degree of WMem effect increasing with increasing disease duration. A larger WMem effect, reflecting poorer WMem capacity, corresponded to poorer performance on neuropsychological measures, and a higher disability score for CDMS patients with the longest disease duration; an observation that suggests wider implication of WMem executive processes with advancing disease. Conspicuously, performance decrements on standard neuropsychological testing did not similarly increase commensurate with disease duration. The ocular motor WMem task appears to meaningfully dissociate WMem deficit from healthy individuals as well as a function of increasing disease duration. Potentially, this task represents a highly informative and objective method by which to ascertain progressive WMem changes from the earliest inception of MS.
AB - Our companion paper documents pervasive inhibitory deficits in multiple sclerosis (MS) using ocular motor (OM) measures. Here we investigated the utility of an OM working memory (WMem) task in characterising WMem deficits in these patients as a function of disease status and disease duration. 22 patients with CIS, 22 early clinically definite MS patients (CDMS: <7 years of diagnosis), 22 late CDMS patients (>7 years from diagnosis), and 22 healthy controls participated. All participants completed the ocular motor WMem task, the paced auditory serial addition test (PASAT), and the symbol digit modalities test (SDMT). Clinical disability was characterised in CDMS patients using the Expanded Disability Severity Scale (EDSS). WMem performance was measured as proportion of errors (WMem errors), saccade latency, and relative sensitivity to WMem loading (WMem effect), an indicator of WMem capacity. All patient groups performed more WMem errors than controls with proportion of WMem errors, and degree of WMem effect increasing with increasing disease duration. A larger WMem effect, reflecting poorer WMem capacity, corresponded to poorer performance on neuropsychological measures, and a higher disability score for CDMS patients with the longest disease duration; an observation that suggests wider implication of WMem executive processes with advancing disease. Conspicuously, performance decrements on standard neuropsychological testing did not similarly increase commensurate with disease duration. The ocular motor WMem task appears to meaningfully dissociate WMem deficit from healthy individuals as well as a function of increasing disease duration. Potentially, this task represents a highly informative and objective method by which to ascertain progressive WMem changes from the earliest inception of MS.
KW - Cognition
KW - Multiple sclerosis
KW - Neuropsychological assessment
KW - Ocular motility
KW - Working memory
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U2 - 10.1007/s00415-015-7644-4
DO - 10.1007/s00415-015-7644-4
M3 - Article
C2 - 25851742
AN - SCOPUS:84929834274
SN - 0340-5354
VL - 262
SP - 1138
EP - 1147
JO - Journal of neurology
JF - Journal of neurology
IS - 5
ER -