Neurological signs and sustained attention impairment in schizophrenia

Both neurological signs and attention impairments are often found in schizophrenia. This study addresses the extent to which neurological signs are related to sustained attention impairment. We assessed subgroups of neurological signs using the standardised Cambridge Neurological Inventory (CNI). Sustained attention was measured using a monotone counting paradigm. After taking into consideration potential confounds such as age, education level and duration of illness, we explored the correlation between sustained attention and groups of neurological signs, as well as with individual signs. We found that "motor coordination" and "disinhibition" signs were significantly related to sustained attention. The correlation with "sensory integration" just failed to reach significance after correction for multiple comparison. "Dyskinesia", "catatonia", "pyramidal" and "extrapyramidal" subgroups were unrelated to sustained attention. The results support the notion of heterogeneity and diversity in neurological signs (even among soft neurological signs) and argue against the use of a single global measure to embrace all soft neurological signs in schizophrenia.