Critical review of clinical trials in senile dementia--II.

The role of dopamine in behavioural arousal and the frequent occurrence of dementia in patients with Parkinson's disease provide the rationale for the use of these substances in dementia, although dopamine levels in the caudate nucleus and substantia nigra are not depressed in primary degenerative dementia (PDD)56. L-Dopa has yielded contradictory results.6 Half of the trials reported an improvement in behaviour, but sometimes at the cost ofimpairment ofmemory, while the remainder found the treatment ineffective. The first studies were carried out in parkinsonian patients and showed an improvement in cognitive performance,57'58 but subsequent trials failed to confirm this effect.59 In a crossover trial in 120 patients suffering from PDD, Schneck et al.' found that the patients responding to L-dopa showed an improvement in psychomotor function and mood, whereas patients responding to choline showed some improvement in memory functions. A few studies have been carried out with amantadine either in elderly deteriorated patients6' or in elderly patients suffering from impairment of memory.62 The efficacy of amantadine was evaluated, using a battery of tests, in a small number of patients who did not meet the criteria of senile dementia. Thus, despite the good results reported, no assessment can be made of the drug's effectiveness in this disease. Nicrosini & Pasotti63 compared piribedil with Codergocrine mesylate in 30 patients suffering from 'cerebral arteriosclerosis', with favourable results and few side effects. Other trials on larger numbers of patients whose clinical status was not much better defined, concluded that piribedil is partially effective."'65 In an open trial bromocriptine was reported to afford a parallel improvement in the electroencephalogram and the motor and memory components of the dementia syndrome.' These clinical findings are at variance with those obtained in two previous controlled trials which produced negative results despite administration of high dosages67 and regardless of the fact that the treatment reduced blood prolactin levels.' In the latter study the period of observation was shorter -4 weeks instead of 12 in the other trials. Gottfries69 reported that some patients with PDD became confused after treatment with bromocriptine and lisuride, another dopaminergic agonist.