[Usefulness of P300 as a tool for diagnosing alterations in sustained attention in ischemic cerebrovascular disease].

INTRODUCTION

Event related potentials, and especially the component P300, can be used to achieve greater precision and sensitivity in the cognitive evaluation of patients. They also enable us to obtain more accurate information about deficiencies in sustained attention, which is a cognitive function associated with the generation of the above mentioned component. Furthermore, the study of disorders triggered off by cerebrovascular disease must be given priority because of the high incidence with which they occur.

PATIENTS AND METHODS

We studied four groups of individuals divided according to the localization of the lesion and the etiopatogenic mechanism involved (10 patients with right parietal atherothrombotic infarction, 10 patients with left parietal atherothrombotic infarction, 10 patients with lacunar infarction, 10 paired healthy controls). They were administered a classic test for obtaining P300, which evaluates sustained attention.

RESULTS

Patients with cerebral infarction in the right hemisphere presented alterations in the functions evaluated, since they showed more omissions, gave fewer correct answers, the values for latency were significantly increased in Fz derivation and amplitude values were reduced in Pz, as compared to healthy controls. Individuals with left cerebral infarction, however, showed no significant differences with regard to the controls. People with lacunar infarction made less mistakes and omissions, and scored more correct answers than those that had suffered right or left infarction. Their amplitude values were also higher than the values of the individuals with a right lesion in Pz derivation but showed no differences as regards the controls.

CONCLUSIONS

These results provide new data on the cognitive mechanisms that are affected during a right parietal lesion and demonstrate the sensitivity of P300 in detecting alterations in sustained attention in individuals that differ as regards not only the localization of the lesion but also the type of etiopathogenic mechanism involved.