Neuropsychological testing to improve surgical management of patients with chronic hydrocephalus after shunt treatment.

Abstract

To find out a practical neuropsychological tool for early and reliable outcome assessment in chronic hydrocephalus. In 30 patients (65 +/- 13 yrs.) 11 neuropsychological tests providing a wide range of psychomotor functions (visual and verbal attention, verbal memory and learning and visuomotor skills) were applied before (pre), one week (early) and 7 months (late) after shunting. After 7 months, clinical outcome was classified according to Stein and Langfitt. Statistics included factor analysis, logistic regression and non-parametric tests. Visual attention ("Digit-symbol"), verbal recall ("10-words-list") and motor precision ("line-tracing") were the most representative (and practical) tests (orthogonal loads > 0.9). These tests, in contrast to others, revealed significant differences between outcome groups concerning early postoperative changes: responder showed marked improvement in visual attention t-scores (47 +/- 8 vs. 41 +/- 8 (pre); p = 0.005) and motor precision scores (109 +/- 26 vs. 149 +/- 47 (pre); p = 0.03). Non-responder even decreased in verbal recall t-scores early after shunting (35 +/- 7 vs. 41 +/- 11 (pre); p = 0.007). By logistic regression, visual attention was most sensitive indicating shunt-response by early psychometric changes (p = 0.04). Psychomotor deficits in hydrocephalic patients can be represented by a few neuropsychological skills: visual attention, verbal recall and line tracing. Since they showed early post-operative differences regarding long-term response to shunting they may offer a practical and standardised method for reliable follow-up.