We recorded somatosensory evoked potentials (SEPs) in scalp EEGs during stimulation of the median nerve, the ulnar nerve and the individual digits in 3 normal subjects and in 1 epilepsy patient. In this patient we also measured SEPs from chronically indwelling subdural grid electrodes during electrocorticography (ECoG). We applied dipole modelling technique to study the 3-dimensional intracerebral locations and time activities of the neuronal sources underlying stimulation of different peripheral receptive fields. The sources underlying median nerve SEPs were located an average of 10.8 mm lateral inferior to those underlying ulnar nerve SEPs. Digit SEP sources showed a somatotopic arrangement from lateral inferior to medial superior in the order thumb, index finger, middle finger, ring finger and little finger, with some overlap or reversal for adjacent digits. The average distance between thumb and little finger was 12.5 mm. Thumb, index finger and middle finger were clustered around median nerve cortical representation, whereas ring finger and little finger were arranged around ulnar nerve cortex. In the epilepsy patient, the source localizations obtained in scalp EEGs showed good agreement with those on ECoGs. We conclude that SEPs recorded in scalp EEGs can be used to study functional topography of human somatosensory cortex non-invasively.

Adult↗

PubMedDate not supplied

Force uncertainty of voluntary movement and human movement-related potentials.

Five movement related potentials, the Bereitschaftspotential (BP), the pre-motion positivity (PMP), the motor potential (MP), the first negative potential during the movement (N1) and the late positive component (LPC) were recorded from human subjects performing right index finger flexions under conditions when the resistive forces (70 N/cm or 10 N/cm) were predictable and when they were unpredictable. The BP was larger prior to the larger force in the certain condition. In the uncertain condition, the BP was similar to that associated with the larger force in the certain condition suggesting that the subjects tended to prepare for the heavy resistance when confronted with force uncertainty. The MP revealed enhanced negativity over the left parietal cortex when the force was unpredictable. The N1 was significantly larger during the high force movement, especially in the uncertain condition. The results support the view that pre-movement compensation for force unpredictability does exist as reflected by the MP over the parietal areas.

Adolescent↗

PubMedDate not supplied

Ambient odor of orange in a dental office reduces anxiety and improves mood in female patients.

Essential oils have been used as remedies for a long time in different cultures across the world. However, scientific proof of such application is scarce. We included 72 patients between the ages of 22 and 57 while waiting for dental treatment in our study. The participants were assigned to either a control group (14 men, 23 women) or to an odor group (18 men and 17 women). Ambient odor of orange was diffused in the waiting room through an electrical dispenser in the odor group whereas in the control group no odor was in the air. We assessed by means of self-report demographic and cognitive variables, trait and state anxiety, and current pain, mood, alertness, and calmness. In this study, we report that exposure to ambient odor of orange has a relaxant effect. Specifically, compared to the controls, women who were exposed to orange odor had a lower level of state anxiety, a more positive mood, and a higher level of calmness. Our data support the previous notion of sedative properties of the natural essential oil of orange (Citrus sinensis).

Adult↗

PubMedDate not supplied

Ataxia of stance in different types of alcohol dependence--a posturographic study.

The aim of this study was to assess the prevalence of ataxia of stance in different types of alcohol-dependent patients. Posturographic measurements were performed in 82 abstinent alcohol-dependent patients and 54 healthy controls in order to analyse postural control. According to Lesch and co-workers, alcohol dependence was classified as total abstinence (Type I), drinking without loss of control (Type II), fluctuating course (Type III), and persistent severe drinking (Type IV). The mechanisms of alcohol dependence in these subtypes can be summarized as follows: Type I patients drink alcohol to counteract symptoms of alcohol withdrawal; Type II patients use alcohol as an agent for solving conflicts; Type III patients drink alcohol to 'treat' an affective disorder; and Type IV patients have a history of pre-alcoholic neurological and/or psychiatric disorders. The neurological examination showed pathological findings in 39%, whereas posturographic measurements uncovered impaired postural control in 61% (chi2 = 8.8, P = 0.003). Comparing the different study groups revealed that ataxia of stance was most common in alcohol-dependent patients classified as Type IV (tau = 0.24, P = 0.005). In conclusion, posturographic measurements are superior to the clinical examination in detecting postural imbalance in alcohol-dependent patients. The prevalence of postural imbalance is highest in patients classified by Lesch as Type IV. Consequently, this type of alcohol dependence -- characterized by pre-alcoholic neurological and/or psychiatric disorders, bears the highest risk of developing ataxia of stance.

Adult↗

PubMedDate not supplied

SPECT and MR imaging in herpes simplex encephalitis.

Two cases of necrotizing herpes simplex encephalitis (HSE) were investigated with 99mTc-hexamethylpropyleneamineoxime (HMPAO) SPECT and MR. The clinical course was compared with the neuroimaging results. In the acute stage, the increased HMPAO uptake matched the MR hyperintense signal in the limbic temporal lobe and in the basal ganglia. Protracted inflammation was accompanied by persistently high HMPAO uptake. The sequelae of HSE were characterized by decreased HMPAO uptake and postnecrotic widening of the temporal horns. The "limbic" pattern recognized in both SPECT and MR reflects the basic pathophysiology and neuropathology of HSE. Both methods may be useful in the diagnosis and follow-up of HSE.

Contrast Media↗

PubMedDate not supplied

Subarachnoid haemorrhage: prognostic factors as related to working capacity.

Seventy-two adult patients suffering spontaneous subarachnoid haemorrhage (SAH) were investigated concerning early mortality. Five patients died within 3 weeks after the onset of clinical symptoms. A demonstrable bleeding source and a Hunt-Hess score greater than 2 were found to be powerful predictive factors for early mortality. Sixty-seven survivors of SAH were examined at an average of 85 months after their first bleeding with regard to working capacity. Various clinical variables and different rating scales during the acute and subacute stage of SAH were identified retrospectively, and their prognostic value for working capacity was investigated. We found that all clinical features at the acute stage of SAH were not predictive of limited working capacity. At the time of discharge, however, organic brain syndrome, focal neurological deficits and a low Barthel Index proved to be significantly related to impaired working capacity. A Hunt-Hess score greater than 2 on admission, and a demonstrable bleeding source, were powerful predictors for early death, but not for impaired working capacity of survivors of SAH.

Adult↗

PubMedDate not supplied

Anticardiolipin-antibodies in stroke and in other neurological disorders.

Anticardiolipin antibodies (ACL-A) are acquired antiphospholipid antibodies characteristically found in patients with systemic lupus erythematosus or related autoimmune diseases. Several reports have shown that there may be an association between ACL-A and various neurological disorders, in particular cerebral ischemia. Using a micropin enzyme linked immunosorbent assay we measured the levels of ACL-A in the sera of 225 unselected patients with various neurological disorders. The prevalence of ACL-A in the whole group was 4.0% (9/225). However, the prevalence in patients with ischemic cerebrovascular disorders was 9.1% (5/55). With one exception (thrombocytopenia was found more often in ACL-A-positive cases) there was no difference with respect to the prevalence of risk factors for stroke and associated diseases between ACL-A-positive and ACL-A-negative patients with TIA/stroke. High titers of ACL-A were also found in a few patients with epilepsy (n = 2), migraine (n = 1), and intracranial meningioma (n = 1). In patients with ischemic cerebrovascular disorders search for ACL-A may help to identify patients with a possibly higher risk of thrombosis.

Adolescent↗

PubMedDate not supplied

Visually induced vertical self-motion sensation is altered in microgravity adaptation.

Vertical vection is a phenomenon of self-motion perception in immobile subjects, which is conventionally perceived in the opposite direction of the upward or downward moving visual stimulus. The Austrian scientific cosmonaut experienced reversed vertical vection from sinusoidal stimulation on third and sixth day of space flight as well as immediately postflight. The occurrence of short periods of reversed vection from constant velocity stimulation six months postflight can be interpreted as a reactivation of an "alternative" visual processing mode. This may indicate that microgravity modulations of the neuronal pathways which process visual information for dynamic orientation are not completely extinguished in the processes involved in readaptation to 1-G.

Adaptation, Physiological↗