Cognitive impairment and optic nerve axonal loss in patients with clinically isolated syndrome

Objective

To investigate cognitive impairment, to assess optical nerve axonal loss, and to determinate whether there is correlation between optical nerve axonal loss and cognition impairment in Clinically Isolated Syndrome (CIS).

Methods

Fifteen CIS patients and 15 controls were submitted to Wechsler memory scale, Rey Auditory Verbal Learning, Rey Complex Figure, Paced Auditory Serial Addition, Digit Span, verbal fluency, stroop color, D2, and Digit Symbol tests. CIS patients were evaluated by optical coherence tomography (OCT) (23 eyes).

Results

CIS patients had worse performance in Paced Auditory Serial Addition Test (PASAT) 2 seconds (P = 0.009) and fluency tests (P = 0.0038). Optical nerve axonal loss was found more frequently in eyes with previous optic neuritis (ON) (85.7%) than in those without previous ON (21.7%) (P = 0.0146). There were no significant correlations between optical nerve axonal loss and cognitive findings.

Conclusions

CIS patients had worse cognitive performance than controls. OCT can detect axonal loss resulting from optical neuritis and subclinical axonal loss in eyes without previous optical neuritis. Optical nerve axonal loss was not correlated with cognition.