Both neurological soft signs (NSS) and cognitive deficits are present among
euthymic bipolar patients. NSS could be related to neurocognitive performance, but this is
not explored thoroughly. Healthy relatives of patients may also suffer from similar
deficits.
This study compared NSS and cognitive functions in euthymic Bipolar I Disorder
(BPI) cases to their non-affected first degree relatives and healthy controls. We also
investigated the association between NSS and cognitive functions in these three groups.
NSS were assessed in three groups using Neurological Evaluation Scale-revised (NES-r).
Eight cognitive domains were assessed in 31 euthymic BPI cases, their 30 non-affected
first degree relatives and 30 healthy controls using Computerized Neurocognitive Battery
(CNB). Euthymic BPI patients had significantly more NSS than non-affected first degree
relatives on 5/7 tests (p-value ranges from 0.042 to p
= 0.0001) and healthy controls on all tests (p-value from 0.042
to <0.0001). Non-affected first degree relatives and controls did not have any
significant difference. BPI participants performed worse than their non-affected first
degree relatives on one neurocognitive domain of CNB (spatial memory accuracy,
p = 0.03) and healthy controls on four domains (spatial memory
accuracy (p = 0.04), abstraction and mental flexibility
efficiency (p = 0.04), spatial memory efficiency
(p = 0.04), and emotion efficiency (p
= 0.04). Non-affected relatives and healthy controls were similar on
neurocognitive domains. Accuracy and efficiency indices of some specific cognitive domains
were negatively associated with AV rating and tap copying NSS ratings.