Gliadin antibodies in older population and neurological and psychiatric disorders.

OBJECTIVES: A variety of neurological and psychiatric disorders have recently been linked to coeliac disease and gluten sensitivity. We here explored whether persistently positive gliadin antibodies (AGA) and coeliac-type HLA increase the risk of gluten sensitivity-related neurological and psychiatric manifestations. The study was carried out in an older population who had consumed gluten for decades but who had no previous coeliac disease diagnosis. MATERIALS AND METHODS: The original study population comprised 4272 randomly selected older individuals, of whom 2089 had AGA and transglutaminase 2 antibodies (antiTG2) measured twice within a 3-year interval. Forty-nine persistently AGA-positive but antiTG2-negative subjects with coeliac-type HLA and 52 randomly selected persistently AGA- and antiTG2-negative age- and sex-matched controls were clinically examined for neurological disorders. The Psychological General Well-Being (PGWB) questionnaire, the SF-36 health survey questionnaire and the Depression Scale (DEPS) were employed to evaluate psychological well-being. The medical files of all the study subjects were analysed for previous illnesses. RESULTS: Persistently AGA-positive but antiTG2-negative older subjects carrying coeliac disease-type HLA did not evince significantly more neurological symptoms or diseases than AGA-negative control subjects (P = 0.682, P = 0.233). There were no statistically significant differences between AGA-positive and AGA-negative groups in psychological well-being and quality of life when measured by PGWB (P = 0.426), SF-36 questionnaires (P = 0.120) and DEPS (P = 0.683). CONCLUSIONS: At population level, persistent AGA positivity did not indicate gluten sensitivity-related neurological and psychiatric disorders.

Event-related brain potentials and the perception of a phonetic continuum.

Competing predictions concerning phoneme discrimination were tested by means of event-related potentials. In research on speech perception, one tradition stems from the physiology of the auditory system whereas another emphasizes categorical perception which involves a marked psychological component. The stimuli were the end points of the Finnish (i)-(y) continuum together with the intermediate boundary sound. Two of these stimuli were presented in each block of trials. One (the 'standard') had a high probability while the other (the 'deviant') was rare. The so-called mismatch negativity (MMN) component of the ERP in response to deviant stimuli showed a large amplitude and short latency when these two stimuli were pure vowels (i) and (y). When the boundary stimulus and one of the pure vowels comprised the stimulus pair, a smaller and more delayed MMN occurred. This result may be taken as support that the discrimination occurs at a basic physiological level. On the other hand, cognitive perception was reflected in the different latencies of the P3 component to (i) and (y). In sum, the results lend support to multilevel hybrid models in the explanation of vowel perception.

Individual alcohol reaction profiles.

The purpose of this study was to evaluate interindividual variation in acute reactions to ethanol. Six young, healthy female subjects participated in a double-blind experiment consisting of two identical alcohol sessions and one control session where glucose was infused instead of ethanol. Alcohol was infused in a standardized way to reach blood alcohol concentration of 1 mg/ml in 1 hr. During the 4 hr-sessions EEG-spectra, smooth pursuit eye movements, various mood variables, BAC and breath alcohol concentrations were studied repeatedly. The results showed that the subjects had a rather repeatable, individual reaction profile as expressed by changes in alpha mean frequency, theta band power, amount of corrective eye movements and subjective intoxication. The sensitivity of the subject to ethanol should thus be expressed as a reaction profile rather than as a change in a single variable.

Men evacuated after the Second World War from the Carelian Isthmus to Southwest Finland: risk group for myocardial infarction?

More myocardial infarctions occurred and the prevalence of diabetes mellitus and hypercholesterolemia (greater than 9.5 mmol/l) was higher among men evacuated in 1944 from Metsäpirtti (Carelian Isthmus) to Vehmaa (Southwest Finland) than among men of the same age native to Vehmaa. Blood pressure, smoking habits, fat intake, physical activity at leisure and mental stress were - according to the questionnaires - equal in both groups. Metsäpirtti and its surroundings was a genetic isolated as compared to Vehmaa. The population of Vehmaa is more mixed and has been influenced by the Germanic (Swedish) race for a long time.

Spectral analysis of visual potentials evoked by sine wave modulated light in migraine.

Visual evoked potentials to unstructured sine wave-modulated light were measured in 30 common migraine patients and 23 controls. The fundamental and the second harmonic components of the response were analysed separately in the frequency domain by power spectrum estimation. The absolute and relative powers of the fundamental component were significantly larger in the patients at 16-22 Hz stimulation both initially, in the onset phase, and later, in the steady-state phase, whereas those of the 2nd harmonic component were smaller in the later stages of stimulation. Significant difference occurred in the dynamics of the 2nd harmonic response between patients and controls. No significant difference was observed at 10 Hz stimulation.

Difference in action between oral triazolam and zopiclone.

The effects of oral triazolam 0.25 mg and zopiclone 7.5 mg in 7 supine volunteers were compared by means of quantitative measurements of the EEG, saccadic eye movements, visual analogue scale (VAS) for alertness, critical flicker fusion frequency (CFF) and the Maddox wing. Zopiclone reached its maximum effect earlier (62 min) than triazolam (91 min; CFF). On linear regression analysis the average rate constant (regression coefficient) of onset of action of zopiclone was significantly greater than that of triazolam (0.29 vs. 0.17). Triazolam and zopiclone had similar effects, but zopiclone seemed to have a faster onset of action, probably indicating swifter absorption in supine subjects. Quantitative EEG evaluation gave parallel results to the other parameters used, but triazolam and zopiclone showed a dissimilar mechanism of action, as characterized by changes in the alpha frequency.

Alpha rhythm in classical migraine (migraine with aura): abnormalities in the headache-free interval.

The alpha rhythm of 18 patients with classical migraine (migraine with aura) was studied by EEG spectrum analysis for evidence of neural abnormalities during the asymptomatic period. The temporal relationship of the findings to attacks was studied by serial records in 11 cases. Increased frequency dispersion and frequency asymmetries of the alpha rhythm were found. The records were, however, mostly normal when separated from attacks by at least 10 asymptomatic days. The abnormalities increased significantly before the onset of prodromal symptoms and clearly outlasted the headache phase. The results give evidence of a fluctuating asymmetric neural disorder in classical migraine.

Quantitative vibration perception thresholds in patients under prolonged antiepileptic treatment.

Quantitative vibration perception threshold (VPT) measurements were performed on 134 healthy subjects and 147 epileptics undergoing prolonged (more than one year) antiepileptic treatment, 28 patients received diphenylhydantoin, 71 carbamazepine and 11 some other drug. 37 subjects received a combination of drugs, which included diphenylhydantoin and/or carbamazepine. VPT was measured quantitatively at the dorsum of the right foot with a device vibrating at 100 Hz. The mean of the four successive threshold values was calculated. VPTs of the epileptic groups treated with diphenylhydantoin, carbamazepine or combined medication were all significantly (P less than 0.001) higher than those of the control group. The group receiving other medication showed no difference in this respect. The percentage of patients with abnormal thresholds was about the same (10-16) in the epileptic groups. An exception was the group taking other medication, in which no abnormal VPTs were found. It is suggested that such quantitative measurement may be a useful screening method for detecting dysfunction in the peripheral nervous system due to prolonged antiepileptic treatment. It will, however, be necessary to test the clinical validity of the method for diagnosing manifest or subclinical polyneuropathies.

Transient asymmetries of steady-state visual evoked potentials in classic migraine.

Unilateral abnormalities in the regional cerebral blood flow (rCBF) and visual evoked potentials (VEPs) during the visual aura of classic migraine have been reported. On the other hand, there are only few observations suggesting unilateral abnormality of neural function during the headache-free period. An experiment is described in which the symmetries of steady state VEPs (SVEPs) are compared in healthy subjects and classic migraineurs in the headache-free interval. In the patients an increased number of strong short-lasting interhemispheric asymmetries was found. In the serial recordings performed, pathologic recordings were obtained intermittently, usually with complete normalisation in the following session. The incidence of abnormalities was relatively independent of the interval between the recording and attack, except for the next few hours. The findings may be related to instability of occipital cortical function in classic migraine.

Difference of steady-state visual evoked potentials in classic and common migraine.

The present study was designed to find evidence for the neural hypothesis of migraine and to evaluate possible interictal differences in the two varieties of migraine by electrophysiological means. Steady-state visual evoked potentials (SVEPs) in response to sinusoidally modulated light were measured in 20 patients with classic migraine and compared with those of 30 common migraineurs and 49 reference subjects. SVEPs to stimuli at 10-24 Hz were recorded occipitally from a pair of midline electrodes and, in classic migraineurs and controls, additionally from left and right occipital areas. The response was processed by the Fast Fourier Transform and automatically analysed. The fundamental component of the midline response to medium frequency stimuli (16-22 Hz) appeared normal in patients with classic migraine, contrary to an augmented response in common migraineurs (ANOVA between groups, P = 0.006). In classic migraine the 2nd harmonic component was attenuated (P less than 0.01 at 18-20 Hz) and the amount of strong interhemispheric f1 asymmetries was increased in about half of the patients. The groups also diverged significantly in the SVEP dynamics during stimulation. The results support the hypothesis of a primary neural disorder in both types of migraine. Different sites and mechanisms of brain dysfunction in classic and common migraine are suggested. Hypothetical neuroanatomical correlates for the abnormalities are presented.

Steady-state visual evoked potentials during migraine prophylaxis by propranolol and femoxetine.

The amplitude of visual evoked potentials (VEPs) for flickering light has been reported to be increased in migraine. In the present study, we have examined whether the VEPs are attenuated when the clinical state of the patient improves during a double-blind experiment with propranolol and femoxetine. VEPs for sinusoidally-modulated light were measured by spectral analysis, and an index depicting the visual reaction type was calculated. The group mean VEP index closely followed the group mean attack frequency, but individual variance was considerable. The changes were most evident in VEPs elicited by stimuli of about 20 Hz. During the treatments, the VEP and headache were also significantly correlated among subjects. The results suggest a close relationship between the enlarged VEPs and the headache mechanisms.

Femoxetine - a new 5-HT uptake inhibitor - and propranolol in the prophylactic treatment of migraine.

The prophylactic effect of a 5-HT uptake inhibitor, femoxetine, was compared with that of propranolol in a double-blind crossover study of 6-months duration. 29 patients commenced the experiment. 3 subjects withdrew because of side effects and 2 because the program was inconvenient for them. In the 24 patients who continued the study to the end, the periods of propranolol (administered 160 mg daily) and of femoxetine (given 400 mg daily) differed significantly from each other with respect to the attack frequency and headache index. A significant reduction in the use of medication relieving attacks was observed during the propranolol treatment as compared with the pre-treatment period. The study showed that partial depletion of thrombocyte 5-HT uptake inhibitor did not lead to a marked improvement in headache, contrary to what might be expected on the grounds of the 5-HT hypothesis of migraine.