The relationship of SPECT scans to behavioral dysfunction in neuropsychiatric patients

Changes in regional cerebral blood flow demonstrated by single photon emission computed tomography in depressive disorders: comparison of unipolar vs. bipolar subtypes

Single photon emission tomography (SPECT) with 99mTc-HMPAO was used to compare regional cerebral blood flow (rCBF) in patients with unipolar and bipolar depression. The study group consisted of 10 unipolar depressed patients and seven bipolar depressed patients who met the DSM-III-R criteria for major depressive disorder (MDD). Nine physically and mentally healthy volunteers served as control subjects. SPECT images were obtained in the patients at two time points: (1) during the major depressive episode before patients had received medication; and (2) at the beginning of the remitted state while patients were receiving antidepressant medication. During the depressive episode, unmedicated unipolar depressed patients showed relatively increased left frontal rCBF compared both with the control subjects and the bipolar patients (P < 0.05). No significant differences in rCBF emerged between the bipolar patients and the control subjects. The data suggest that unipolar depressed patients, unlike bipolar patients, have relatively increased rCBF in the left frontal lobes during the depressive episode, but these differences tend to disappear during the period of remission.

rCBF SPECT in Parkinson's disease patients with mental dysfunction

Functional imaging of the brain using SPECT provides information correlative to the alterations of regional blood flow. In this paper we review the literature pertaining to SPECT in Parkinson's disease with and without dementia and depression. Parkinson's disease itself is not associated with a consistent pattern of cerebral blood flow alterations in the basal ganglia, but reduced parietal blood flow is more often reported. The heterogeneity of blood flow changes possibly reflects the multifactorial pathophysiology of the disease. In demented Parkinson's disease patients frontal hypoperfusion is often found or bilateral temporoparietal deficits, probably indicative of concomitant Alzheimer's disease. The SPECT studies undertaken in depressed patients with and without Parkinson's disease show highly conflicting and inconsistent results, probably due to methodological and diagnostic flaws (especially the inclusion of demented Parkinson patients). Several lines of reasoning point to a prefrontal dysfunction and future SPECT studies are planned to study this region in non-demented Parkinson's disease patients with and without major depression.

Legal and medical aspects of liability for negligently occasioned nervous shock: a current perspective

This article examines recent developments in Australian and English common law relating to negligently occasioned psychiatric illness (nervous shock) in the light of advances in understanding of aetiology, neurophysiology and psychology of emotional injury. The legal analysis focuses on the modern concept of proximity relationship between the plaintiff and the defendant. The courts use the notion of proximity to determine the existence of duty of care in cases involving liability of the defendant for the negligent infliction of 'mere' nervous shock; that is where the plaintiff who had not been present at the site of the accident in which a close relative or a co-worker has been negligently killed or injured, claims to have suffered a lasting psychoneurosis or a psychosomatic illness as a result of a sudden and severe emotional distress occasioned by the defendant's wrongful act. Cases from the US, [1] Canada, [2] South Africa [3] and New Zealand [4] are not discussed; to include them would have involved too much exposition in comparison to their influence upon the development of the law of nervous shock. Nevertheless, since the developments described below concern the core question of law, the nature and the ambit of defendant's liability for unintentionally occasioned psychiatric damage, they will have to be considered in any jurisdiction in which this question arises.

Regional cerebral blood flow in unipolar depression measured with Tc-99m-HMPAO single photon emission computed tomography: negative findings

Recent studies have reported that patients with unipolar major depression may show a lower whole brain cerebral blood flow (CBF) and reduced regional CBF in frontal, temporal, and parietal lobes. The present study used single photon emission computed tomography (SPECT) with the CBF marker Tc-99m-hexamethylpropyleneamineoxine (HMPAO) to measure the cortical CBF of six individual regions of interest (ROIs), total ROI, and left or right hemispheric total ROI in 43 unipolar depressed subjects and 12 normal control subjects. There were no significant differences in the distribution of Tc-99m-HMPAO uptake into total ROI, right or left global ROI, prefrontal, motor frontal, parietal, temporal, visual cortex, or associative visual cortex between patients with melancholic depression, simple major depression, or minor depression and healthy control subjects. There were also no significant differences in the right-left distribution of uptake between the patients and the control subjects. Hypoperfusion was observed in motor frontal and parietal cortex of patients who had been taking benzodiazepines during the study period. It is concluded that cortical CBF, as assessed with Tc-99m-HMPAO SPECT, is relatively intact in the present sample of patients with severe depression.