Auditory event-related potentials in post- and prelingually deaf cochlear implant recipients

The development of central auditory functions in cochlear implant (CI) patients was studied over six months of rehabilitation. Examinations were performed beginning with the first week after processor calibration, and in monthly follow-up sessions thereafter. The subjects were given a simple auditory perception task (detection of a 400 Hz and a 1450 Hz tone), as well as an oddball-paradigm (detection of one of the tones as a rare deviant). Auditory evoked potentials, reaction time and errors were recorded. Results from five patients, two postlingually deaf and three prelingually deaf CI recipients are shown. Generally, in the auditory evoked potentials of patients a shortening of N100 latency towards those of subjects with normal hearing was seen from month to month. However, in the prelingually deaf patients this effect was weaker and more variable over time. Three CI recipients showed a P300 component in the oddball-paradigm in correlation with their performance. Two prelingually deaf patients failed to show a P300 in the oddball-paradigm. For both components, the N100 and the P300 we found a larger spreading over the skull in the patients compared to a normal hearing person. The results show that from the very first days after initial processor fitting prelingually and postlingually deaf CI recipients may show cortical correlates of stimulus processing and discrimination. For some components of the auditory evoked potentials an initial temporal change but a maintained larger spreading over the skull was seen.

Biochemical markers in synovial fluid identify early osteoarthritis of the glenohumeral joint

The objective of this study on the glenohumeral joint was to assess the (1) accuracy of clinical diagnosis of osteoarthritis compared with arthroscopic diagnosis, and (2) the ability of biochemical markers in synovial fluid to detect osteoarthritis. Patients (96) were examined clinically and the preoperative diagnosis of osteoarthritis was recorded. At surgery (arthroscopy or arthroplasty), the glenohumeral joint was inspected for signs of osteoarthritis, and the joint osteoarthritis grade (I-IV) was recorded. At surgery, synovial fluid lavage was obtained from the joint, and later analyzed to determine levels of aggrecan components: total sulfated glycosaminoglycan and keratan sulfate epitope, link protein and the chondroitin sulfate epitope recognized by antibody 3B3 (3B3(-)). Compared with arthroscopic diagnosis of osteoarthritis, the results showed that the clinical diagnosis did not wrongly identify joints without osteoarthritis, and was always able to identify joints with advanced (Grade IV) osteoarthritis. Grade II osteoarthritis was rarely identified (10% of the time), and Grade III osteoarthritis was identified 50% of the time. Biochemical assessment of the synovial fluid showed that the catabolic markers (sulfated glycosaminoglycan, keratan sulfate and link protein) were elevated in fluids from joints with moderate (Grade III) and advanced osteoarthritis (Grade IV), and the 3B3(-) epitope was elevated in Grades II, III, and IV. These results show that arthroscopic diagnosis for osteoarthritis, of the glenohumeral joint is particularly useful for early and moderate osteoarthritis, where clinical (nonarthroscopic) diagnosis is poor, and that biochemical analysis of the synovial fluids corresponds well to arthroscopic diagnosis of shoulder osteoarthritis.

[The effect of valproic acid monotherapy on behavior and cognitive performance of children with idiopathic generalized epilepsy]

Valproic acid (VPA) currently plays an important role in the treatment of several different types of epilepsy. Especially in children and adolescents, VPA is used because of a minimum of adverse effects and generally little impact on cognitive and psychomotor functions. However, reports in the literature regarding the influence of VPA on behavior and cognitive performance and on EEG parameters vary widely. We investigated the effect of VPA monotherapy on behavioral components (attention, concentration, inhibitory control), cognitive efficiency (motor reaction time, learning, retention) and evoked potentials in 19 children aged 6 to 14 years with idiopathic generalized epilepsy and compared the results with those of healthy controls matched for age. In addition, we analyzed the serum levels of VPA and some of the VPA metabolites in all of the children with epilepsy immediately before the psychophysiological assessments. Our results show marked differences between the children with epilepsy and the healthy controls in all types of behavior and cognitive performance assessed. Abnormal behavior (disturbances of attention and concentration, impulsive behavior patterns) and significant changes in evoked potentials appear to be correlated with serum levels of VPA and certain VPA metabolites.

[Idiopathic varus gonarthrosis: diminished nociceptive vs. unchanged somatosensory sensitivity]

Neuromuscular control deficits are supposed to contribute to the development of osteoarthritis (OA). Pain measurements were performed to clarify whether nociceptive afferents differ between OA patients and healthy subjects. Thermal pain thresholds were significantly higher in OA subjects as compared to controls, but there was no difference in perceptual thresholds after electrical stimulation. Lateralization, gender, site of OA changes, previous operations, or medication did not affect these findings.

[Extra-articular pathogenetic factors in arthritis and deformities in old age as exemplified by varus gonarthrosis]

Extraarticular, predominantly neuromuscular, factors are thought to contribute to the development of osteoarthritis. With increasing age, changed temporal dynamics of motor reflexes and reduced muscular force may affect the efficacy of neuromuscular protection of the knee joint. In three experimental studies conducted with osteoarthritis patients and healthy controls, no difference was found in monosynaptic reflex times and latencies of somatosensory evoked brain potentials. Muscular force was generally diminished in the patients, with the most prominent reduction during coxal abduction. Osteoarthritis patients had marked nociceptive hyposensitivity, but no difference was seen in fast conduction afferent systems. In an animal study with high locomotion load, interruption of articular afferent nerve fibers led to a precipitation of cartilage degeneration. It is concluded that minor extraarticular functional deficits acting over time, probably support and aggravate the development of osteoarthritic changes.

The effect of fluorescent whitening agent on hunter camouflage clothing

Fluorescent whitening agents (FWAs) are chemicals added to most fabrics and papers during manufacture to increase color temperature, "whiteness," and "brightness." FWAs accomplish this by absorbing energy in the ultraviolet (UV) part of the spectrum and emitting it as visible blue light. Recently, hunters have become concerned that FWA could be reducing the effectiveness of their camouflage clothing. As a result, some manufacturers have begun making their camouflage clothing (camo) without FWA, and a spray-on product has been introduced to block the action of FWA. Radiometric spectra from camo and foliage samples suggest, however, that these concerns might not be fully justified. Under full sun and in the shade, spectra from 300 to 500 nanometers (nm) (i.e., UV and visible blue light) showed that camo samples containing FWA matched the foliage reasonably well. No evidence of a major problem caused by the FWA was detected, and no significant need for the use of UV absorbing dyes to block the action of FWA was found.

Smoking deprivation in "early" and "late" smokers and memory functions

Reports on smoking and nicotine effects upon memory are contradictory: improvement, no change, and impairment have been observed. These inconsistencies may be due at least in part to different types of learning tasks and to experimental designs: in most studies, acute nicotine effects were analysed after previous smoking deprivation. This study compared learning, retention, and retrieval between nonsmoking after previous deprivation and "usual" smoking without previous deprivation. Twenty female smokers (S) participated in two sessions, between 8.00 and 11.00 a.m. The Austin maze and a Word Recognition Task (WRT) were applied. During the WRT, ERP were recorded from Fz and Cz scalp locations. Heart rate, CO, and subjective ratings (dizziness and smoking need) but neither WRT nor maze performance discriminated between deprivation and smoking. However, significant differences were obtained between those Ss who usually start smoking within 1 h after getting up (ES) and those who start later (LS). In maze learning and WRT, LS performed better when deprived than smoking, and ES performed better when smoking than deprived, i.e. when the time of the tests met their usual smoking habits. Results are discussed in terms of a modulation of smoking effects on memory functions by the Ss' internal state.

Refractive-index measurements for the correction of particle sizing methods

For many optical methods in liquid particle sizing the refractive index of the liquid must be known. There is no problem if the data are available in the literature. If the liquid is unknown or if the refractive index changes because of a heating process or chemical reactions, the refractive index must be measured to achieve accurate sizing. A method is presented to determine the real part of the refractive index of droplets using the shift in the position of the first rainbow. Results from the application of this method to burning droplet streams are presented.

Visual acuity degradation resulting from dispersion in polycarbonate

Visual acuities (VA) were measured through a series of prisms in order to quantify the blur that results from dispersion in polycarbonate. The mean VA of 40 eyes was reduced from a starting level of 20/13 unaided to 20/31 through 16 prism diopters of polycarbonate. The decline was a linear function of prismatic power. The blurring effect of polycarbonate was significantly greater than that of CR39. The blur from polycarbonate was found to be great enough that it should be taken into account whenever polycarbonate is considered for spectacle lenses. A graphical display is provided which can be used by the clinician to predict the degree of blur from a known polycarbonate lens.

Coincidence of attention deficit disorder and atopic disorders in children: empirical findings and hypothetical background

ADDH children are often reported to display signs of allergies to various substances and/or atopic (AT) symptoms (i.e., atopic eczema, hay fever, or asthma). Since, at least for a subgroup of these children, a common biological background for both ADD and atopy may be assumed that may involve brain catecholamines, our hypothesis was that in a group of AT children (mainly atopic eczema) signs of ADD should appear more often than in controls. Parental hyperactivity ratings revealed a significantly higher frequency of ADD symptoms in the AT group, and laboratory tests sensitive to attentional capacity and inhibitory functions showed poorer performance in the AT children, the findings being similar to those reported in hyperactives. Thus, our results add support to the assumption of a common predisposing factor for both AT and ADDH in a subgroup of children.

Effects of cigarette smoking upon frequencies of EEG alpha rhythm and finger tapping

Under the influence of nicotine, an increase in EEG alpha frequency as well as finger tapping speed has been reported from separate experiments, and it has also been shown that tapping and alpha frequencies may correlate in defined experimental settings. The present study aimed at the analysis of smoking effects using parallel recordings of both EEG and finger tapping. Twelve healthy subjects were tested in two sessions (smoking deprivation versus smoking). After smoking, both dominant alpha frequency (P less than 0.05) and tapping performance (P less than 0.001) were higher than during deprivation. In most subjects, the increase of both parameters developed in parallel, and during phases of very stable tapping the ratio of alpha and tapping frequencies was close to 2:1. Both frequencies correlated during the deprived (r = 0.6108, P = 0.035) as well as the smoking (r = 0.7009, P = 0.011) conditions. Results confirm earlier findings regarding the effect of smoking upon EEG and tapping, and the parallel changes of both parameters may be attributed to the pharmacological properties of nicotine. Besides possible peripheral and spinal effects of nicotine, the increase of tapping performance parallels the increased frequency of central nervous pacemakers.

Effect of perinatal dexamethasone treatment on conditioned taste aversion in rats

Effect of perinatal dex Rats received a single subcutaneous injection of 1 mg/kg dexamethasone at the age of seven days. One hundred days after the treatment, conditioned taste aversion was determined in the adult animals. Perinatally applied dexamethasone did not affect water consumption but caused a significant attenuation of conditioned taste aversion. These findings may be explained by dexamethasone effects upon brain development which cause impairment of memory functions or, alternatively, decreased responsiveness to aversive stimuli.

[The effect of coupled cardiovascular and respiratory afferent signals on the central processes of human information processing]

On the basis of contemporary knowledge on close functional connections between respiratory and cardiovascular afferents a computerized experimental device was developed by means of which central information processing can be studied in dependence on respiration phase and the level of baroreceptor activity. In all the examined parameters (time of motor reaction of two hands, latency of eye-lid reflex) the greatest changes were observed at maximum baroreceptor activity. These changes were clearly distinguished by direction during the phases of inhalation and exhalation. Such effect is probably based on the fact that the influence of cardiovascular afferents on the level of central activity is modulated in respiration rhythm through the mechanism of breath "gating" of postsynaptic STN structures.

Relations between slow (4 cps) EEG activity, sensorimotor speed, and psychopathology

Slow rhythmic activity (SRA) in the frequency range from 2.5 to 5.0 cps was studied in 20 subjects (Ss) in order to examine its effect upon sensorimotor reactions and its possible relationship to psychological findings. With monopolar EEG derivations, maximal power density of SRA is found in frontal regions, whereas bipolar leads reveal maximum occurrence of SRA over posterior areas. Reaction times (RT) to visual and auditory stimuli increase significantly during the occurrence of SRA; the amount of this prolongation (ca. 74 ms) is independent of stimulus modality but significantly correlates with SRA frequency: the lower the frequency, the higher the RT increment. In psychological tests, most Ss with SRA displayed disturbances of emotionality as well as 'pathological' values in the subscales hysteria, hypochondria, psychasthenia, and paranoia, but none of our Ss was diagnosed as psychotic. There is a high correlation between the SRA frequency and the extent of psychological deviations: Ss with low SRA frequency values are more likely to reveal psychological disturbances than Ss with high SRA frequency. The possible origin and physiological impact of SRA is discussed and the desirability of further neurophysiological studies is emphasized.

Does neurology inform psychoanalysis? A case report

In these days of malpractice suits it has become increasingly important that the psychoanalyst make correct diagnoses and institute appropriate treatment. The significance of this statement is enhanced by the fact that the opinion is being increasingly enunciated that there is no such disorder as conversion hysteria. Accordingly the psychoanalyst needs to keep up to date about relevant neurological matters. The present article reports a case of a young women who had been treated psychoanalytically for many years without the organic nature of her disorder being grasped. Appropriate pharmacological therapy produced prolonged remission of her symptoms.

A new approach to cerebral asymmetry: RT differences in simultaneous bimanual finger movement during verbal and nonverbal tasks

This study was aimed at testing a new approach for examination of functional laterality based on hemispheric specialization. The subjects had to perform verbal (words/nonwords) and nonverbal (similar/different patterns) discrimination. The separation of the two hemispheres during information processing was realized by requiring a simultaneous response of both index fingers. The obtained over-all reaction times (RT) were faster for verbal than for pattern tasks. Considering the RTs for solely the particular, faster response of one or the other index finger, the right index finger turned out to be faster on verbal tasks whereas the left one dominated on pattern tasks. According to the hypothesis that the faster hand indicates the more active (contralateral) hemisphere, it can be assumed that words are responded to more quickly when processed in the left hemisphere. On the other hand, patterns are responded to more quickly when the right hemisphere is active. These results suggest that each hemisphere may be capable of processing verbal and nonverbal material; the speed of information processing, however, is faster in the more adept one.

Increased locomotor activity of rats by self-stimulation in a running wheel

A method was developed in which the intracranial self-stimulation of rats was dependent on their locomotor activity. During each rotation of a running wheel (= 0.75 m), six stimulus trains were administered via electrodes in the medial forebrain bundle. Under these conditions, animals increased their locomotor activity 112-fold, compared to a control condition without self-stimulation. This method may be a valuable procedure in various research fields where extreme increases in motor activity of laboratory animals are advantageous.