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Some forms of behavioral perseveration may reflect the disruption of specific neurotransmitter systems including mesencephalic dopaminergic projection. We present an open-labeled trial of a dopamine agonist for treating perseveration in dementia. Eight patients with ischemic vascular or degenerative dementia completed a 25-day trial of bromocriptine with a maximum daily dose of 10 mg. Patients were assessed with neuropsychological scales and a test battery for detecting perseveration. Recurrent and stuck-in-set types of perseveration significantly improved during the treatment, whereas measures for general attention and overall cognitive function showed no significant changes. We assume that bromocriptine supplemented the mesolimbocortical or ventral mesostriatal dopamine system ameliorated a certain frontal lobe function such as focused attention or working memory and improved the patients' perseverations. Although this study is preliminary because of the small sample size and open-labeled design, the results underline the possibility of pharmacotherapy for perseveration and recommend a double-blind, placebo-controlled study.

Objective: This study examined the effects of ACTH 4-10, a fragment of adrenocorticotropin (ACTH) with known central nervous system (CNS) activity, on the dimensional complexity of the ongoing electroencephalographic (EEG) activity. Stressful stimuli cause ACTH to be released from the pituitary, and as a neuropeptide ACTH may concurrently exert adaptive influences on the brain's processing of these stimuli. Previous studies have indicated an impairing influence of ACTH on selective attention., Methods: Dimensional complexity of the EEG, which indexes the brain's way of stimulus processing, was evaluated while subjects performed tasks with different attention demands. Sixteen healthy men (23 to 33 years) were tested once after placebo and another time after administration of ACTH 4-10 (1.25 mg intravenously (i.v.), 30 minutes before testing). The EEG was recorded while subjects were presented with a dichotic listening task (consisting of the concurrent presentation of tone pips to the left and right ear). Subjects either a) listened to pips in both ears (divided attention), or b) listened selectively to pips in one ear (selective attention), or c) ignored all pips., Results: Dimensional complexity of the EEG was higher during divided than selective attention. ACTH significantly increased the EEG complexity during selective attention, in particular over the midfrontal cortex (Fz, Cz)., Conclusions: The effects support the view of a de-focusing action of ACTH during selective attention that could serve to improve the organism's adaptation to stress stimuli.