Ocular motor measures of cognitive dysfunction in multiple sclerosis II: working memory

Area of Science:

• Neuroscience
• Ophthalmology
• Cognitive Psychology

Background:

• Multiple Sclerosis (MS) is characterized by pervasive neurological deficits.
• Ocular motor (OM) measures have previously shown inhibitory deficits in MS.
• Working memory (WMem) impairments are common in MS but require sensitive characterization.

Purpose of the Study:

• To evaluate an OM WMem task for characterizing WMem deficits in MS patients.
• To assess the relationship between WMem deficits, disease status, and disease duration in MS.
• To compare the sensitivity of the OM WMem task with standard neuropsychological tests.

Main Methods:

• Recruited 22 CIS, 22 early CDMS, 22 late CDMS patients, and 22 healthy controls.
• Administered an OM WMem task, PASAT, and SDMT.
• Measured WMem errors, saccade latency, and WMem effect (capacity indicator); assessed EDSS for disability.

Main Results:

• All MS patient groups exhibited more WMem errors than controls.
• WMem errors and WMem effect magnitude increased with disease duration.
• Greater WMem effect correlated with poorer neuropsychological performance and higher disability in late CDMS patients.
• Standard neuropsychological tests did not show similar increases with disease duration.

Conclusions:

• The OM WMem task objectively differentiates MS patients from controls and tracks WMem decline with disease progression.
• This task offers a sensitive method for monitoring WMem changes from early MS.
• OM WMem assessment may be more informative than standard tests for long-term MS management.