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Biomedical subjects

D M Psatta

Publications and source records attributed to D M Psatta.

At least 19 recordsLinked to original sources

Vasotocin improves intelligence and attention in mentally retarded children.

In mentally retarded (MR) prepubertal children, investigated both before and after six months of treatment, synthetic arginine vasotocin (AVT) (10(-6) mg/day/0.1 ml, intranasally), but not oxytocin or saline alone, significantly increased the intelligence quotient (IQ) and improved the attention parameters without affecting the short-term memory. Taking into account both the psychometric results and the clinical observations, the effects of AVT could be mainly explained by assuming the improvement of attention. Since there was a significant inverse correlation between the pretreatment levels of the IQ and attention scores and their increase after AVT, and since the AVT effects tend to be more intense in autistic children, we hypothesize that the more affected the attention mechanisms, the more they are sensitive to AVT. The present results are tentatively explained by the paradoxical sleep-enhancing properties of AVT, mechanisms by which AVT could improve the brain plasticity in MR subjects and by this, the attention performance.

Attention

Age-dependent amplitude variation of brain-stem auditory evoked potentials.

Normative amplitude values of brain-stem auditory evoked potential (BAEP) components are given for normally hearing subjects at 1, 10, 30, 50 and 70 years of age, with an intragroup age variation of only +/- 6 months. Under these circumstances amplitude standard deviations decreased to less than 20% of the mean values. In contrast with the reduced evolution of latency with age, BAEP amplitude (for components I-V) undergoes a greater oscillation during ontogeny. With the exception of component I, it increased markedly from 1 year to 10 years of age and decreased thereafter constantly up to 50 years, with a mean rate of 10 nV yearly. The decrease slowed down between 50 and 70 years. The amplitude differences between the subgroups are highly significant statistically (P less than 0.01). Possible reasons for these changes are discussed.

Adolescent

Effects of feedback caudate nucleus stimulation on spontaneous fast amygdaloid spindles and drive.

Experiments with single and repetitive stimulation of the head of the caudate nucleus (4-10 V, 0.3 msec) triggered by occurrence of fast amygdaloid spindles (35 c/s microV, 0.5 sec) were performed in six animals with chronically implanted cerebral electrodes. In conjunction with the anterior cortical recruiting response the stimulation increased the incidence of amygdaloid fast spindles and decreased the incidence of hippocampal theta activity and of searching eye movements. The associative training failed, however, to significantly modify in the background EEG, the mean incidence of the fast amygdaloid spindles or the rate of the sensorimotor rhythm of 12-18 c/s. Its only effect (after long repetition) was a displacement to the right of the regression line of the incidence of the two rhythms and a slight alteration in the slope. The possibility of activating the caudate nucleus inhibitory effects through the amygdala during internal inhibition phenomena is discussed.

Amygdala

Mapping of VEPs and ERG responses to punctual stimulations in the visual field.

Visual field projection maps were obtained using retinal and cortical EP amplitude values. Single meridian investigations were also performed. Stimulation was done with punctual photic stimuli delivered by the LED perimeter built for the purpose. Schedule with 28 stimulation loci was adopted. The B wave of the average ERG and P100 component of the cortical VEP were measured. The maps were obtained by interpolation of amplitude values on a grid of 21 x 21 characters. By comparing the retinal and cortical visual field maps, conclusions regarding the normality of visual structures (peripheral or central) can be drawn. Our procedure adds to the previous data on visual field investigation (cynetic or static) important elements concerning vision electrophysiology.

Brain Mapping

Cerebral dysfunction revealed by EEG mapping in the schizoform epileptic psychosis.

Twenty schizophrenia-like psychotic patients suspected of epilepsy were explored using EEG techniques (recordings in the 10-20 International System, source derivation, EEG mapping and EEG spectral reaction mapping by photic and somesthetic stimulation). In 16 of them, latent epileptic disorders were found. EEG spiking foci could be located either: (a) in temporal, (b) fronto-basal, or (3) in the sagittal-line leads. A corresponding associated dysrhythmia was clearly revealed by EEG mapping. On EEG spectral reaction mapping a suggestive aberrant displacement of the area of maximal sensory response was found. These EEG disorders were in significant relation with the psychotic syndrome observed in the respective group of patients: (a) patients with fronto-basal (temporal anterior) foci were prevalently paranoid; (b) patients with temporal lobe foci were prevalently depressive; (c) patients with sagittal line (singular) foci presented a predominantly expansive, hypomanic behaviour. The study shows the importance of normal fronto-limbic circuits for the preservation of mental health.

Adult

EEG mapping in mentally retarded children by synthetic arginine vasotocin administration.

EEG investigations (using source-derivation) were performed in 15 mentally retarded children, before, during (at 1 and 6 months) and after three months of pineal hormone treatment (AVT, 10(-6) mg/day, intranasally). Power spectral analysis, maturation lines and EEG mapping were used to ascertain the functional changes induced by AVT. A rapid increase in maturation EEG coefficients was found. It resulted from a significant reduction in the percent amount of theta and delta activity and from the increase in alpha activity. A significant increase in alpha peak frequency occurred after 6 months of treatment as well as a better separation of the EEG patterns between the anterior and posterior halves of the hemispheres. These favourable effects were clearly evidenced by EEG mapping. They are in good relation with cognitive function (attention, intelligence) improvement induced by AVT therapy.

Administration, Intranasal

Contribution of EEG mapping to diagnosis setting in a supratentorial damage.

Forty neurologic patients were investigated in order to disclose the diagnostic advantages by power ratio EEG mapping. Typical examples of EEG maps in brain tumours, cerebral infarction, encephalitis and epilepsy are given. In spite of obvious limitations, the necessity of EEG mapping utilization in the neurological clinic is supported.

Adult

Alterations in brain-stem auditory responses induced by head down tilting in hypertensives with supine brain-stem disorders.

The influence of head down (HD) tilting on brain-stem auditory evoked responses (BAER) was studied in hypertensives with supine brain-stem disorders (occipital headache, vertigo, nausea, diplopia, blurred vision occurring after night recumbency), in hypertensives without such phenomena and in normotensives. In the latter two categories of subjects HD tilting had no effect on BAER. On the contrary, in hypertensives with supine brain-stem disorders the manoeuvre induced a constant prolongation of I-V and III-V intervals and a depression in the amplitude of wave V; the alterations of BAER produced by HD tilting reveal probably a dysfunction of the superior brain-stem area and might be due to the impaired cerebral venous draining subsequent to the manoeuvre. The study of BAER after HD tilting seems to be a proper means to attest the supine brain-stem disorders displayed by some hypertensives.

Brain Ischemia

Diabetes insipidus in a patient with suspected multiple sclerosis.

A 53-year-old man developed spastic ataxia associated with diabetes insipidus. The patient experienced frequent attacks of stiffness and numbness of the four limbs accompanied by difficulty of speech. During an eight years' follow-up a progressive deterioration of the motor function was observed but no extracerebral manifestations were noticed. The association of spastic ataxia is generally considered as diagnostic of histiocytosis X. In the present case, however, multiple sclerosis seems a more likely diagnosis in view of the late onset and the highly characteristic brain stem seizures.

Ataxia

Somatosensory evoked potentials in patients with sensitive dissociation.

The purpose of the study was to reconsider the somatosensory evoked potential (SEP) morphology in case of thermalgic versus proprioceptive sensory loss. The study was carried out on 70 inpatients affected by uni- or bilateral dissociated sensory disorders and on 45 normal controls. The median or tibial nerves were stimulated (at wrist or ankle), the stimulus intensity being adjusted to elicit a visible muscle response with liminal pain. SEPs were measured with regard to 7 negative components parameters (latency, amplitude) and statistically compared in the three groups. Results show that the initial SEP components (N18, N30, N70) are specifically affected in case of proprioceptive and the late components (N150, N220, N340) in case of thermalgic sensory disorders (N150 having an intermediate position). The intergroup differences were statistically significant. The results are thought to be used in clinical diagnosis.

Adolescent