ATTENTIONAL DEFICITS IN PARKINSONS-DISEASE - PARTIAL REVERSIBILITY WITH NAPHTOXAZINE (SDZ NVI-085), A SELECTIVE NORADRENERGIC ALPHA(1) AGONIST

Several authors have suggested that catecholamine depletion may affect attentional processes in human subjects and could be implicated in th e frontal lobe syndrome that has been described in Parkinson's disease (PD). The present study reports the effects of a placebo and naphtoxa zine (SDZ-NVI-085), a selective noradrenergic a, agonist. These substa nces were administered to nine parkinsonian patients who were assessed on measures of attention, including neuropsychological tests and evok ed potentials. The results indicate that naphtoxazine may improve perf ormance on some tests of ''frontal functions,'' including the Stroop a nd the Odd-Man-Out tests, which have been previously found to be affec ted in PD. However, the results of some other neuropsychological tests of frontal function were not affected by naphtoxazine. Specific evoke d potentials such as the Nd1 and Nd2 curves-which are thought to refle ct attentional processes and which have been found to be affected in P D-were improved by naphtoxazine. Finally, naphtoxazine reduced the per centage of errors and restored the lateralization of N100 during the S hifting Reaction Time Task, suggesting that this substance may act on the processes underlying the shifting deficit in these patients. The r esults are discussed in terms of the specific cognitive processes that may be affected by naphtoxazine and in terms of the role of the norad renaline in attentional deficits found in PD.