Sex differences in pudendal somatosensory evoked potentials.

BACKGROUND: Somatosensory evoked potentials (SEPs) of the pudendal nerve are a well-established diagnostic tool for the evaluation of pelvic floor disorders. However, the possible influence of sex differences on response latencies has not been established yet. The aim of this study was to standardize the procedures and to evaluate possible effects of gender differences on anal and penile/clitoral SEPs. METHODS: The anal and dorsal penile/clitoral SEPs were recorded in 84 healthy subjects (40 males and 44 females; mean age 47.9 ± 16.6 years, range 16-81 years; mean height 168.3 ± 20.3 cm, range 155-187 cm). Pudendal SEPs were evoked with a bipolar surface electrode stimulating the clitoris or the base of the penis and the anal orifice and recorded using scalp electrodes. The latency of the first positive component (P1) was measured. The effect and possible interaction of (a) stimulation site and (b) gender on the two variables was explored by multivariate analysis of variance (MANOVA). RESULTS: The examination was well tolerated and a reproducible waveform of sufficient quality was obtained in all the subjects examined. In the female subjects, a mean cortical P1 latency of 37.0 ± 2.6 and 36.4 ± 3.2 ms for anal and clitoral stimulation, respectively, was found. In the male subjects, the cortical latencies were 38.0 ± 3.5 ms for the anal stimulation and 40.2 ± 3.7 ms for the penile stimulation. At MANOVA, a statistically significant main effect of stimulation site and gender as well as a significant interaction between the two variables was found. CONCLUSIONS: Anal and dorsal penile/clitoral SEPs represent a well-tolerated and reproducible method to assess the functional integrity of the sensory pathways in male and female subjects. Obtaining sex-specific reference data, by individual electrophysiological testing, is highly recommended because of significant latency differences between males and females, at least as far as penile/clitoral responses are concerned.

Cerebral Whipple's disease as a cause of reversible dementia.

We describe a case of reversible dementia caused by Tropheryma whippelii (TW). Diagnosis was confirmed by a positive polymerase chain reaction for this pathogen both on serum and cerebrospinal fluid. Specific antibiotic therapy resulted in distinct clinical and neuroradiological improvement. Control polymerase chain reaction for T. whippelii on serum and cerebrospinal fluid was negative.

Motor evoked potentials recorded from external anal sphincter by cortical and lumbo-sacral magnetic stimulation: normative data.

Electrophysiological activation of the motor pathways can be obtained by electrical or magnetic stimulation. The latter has the great advantage of being painful and able to stimulate deeply situated nervous structures. Only a few reports describe responses obtained from pelvic floor muscles and external anal sphincter (EAS) by transcranial and lumbo-sacral magnetic stimulation. Our purpose is to present normative data of motor evoked responses from EAS in a group of healthy subjects (age range 19-80 years) using a standardized protocol of magnetic stimulation. Nine females and 7 males, with a mean age of 52.63 years, were included in this study. They had no known neurological and gastrointestinal disease. Magnetic shocks were delivered by a Magstim 200 (Novametrix) and a circular coil, centered on the vertex and on the lumbo-sacral region. Electromyographic recordings were taken from EAS using needle electrodes. The cortical magnetic stimulation was performed in two conditions: at rest and during a mild contraction of pelvic floor muscles. The mean values of motor evoked potentials (MEPs) latencies after cortical stimulation were 26.92+/-3.01 ms at rest and 23.31+/-2.70 ms during facilitation. Motor latency after lumbo-sacral root stimulation was 6.09+/-1.43 ms. The MEPs from EAS are easily obtained and stably reproducible in normal subjects. It can be suggested also as a useful adjunct in the assessment of faecal incontinence.

[Clinical and instrumental diagnosis of Alzheimer's and multi-infarct dementia]. / Diagnosi clinico-strumentale nello studio della demenza di Alzheimer e nella demenza multinfartuale.

We investigated the possible correlation between functional and anatomical imaging techniques and clinical exams in patients with Alzheimer's and vascular dementia. We examined 24 patients affected with dementia, 16 of them with Alzheimer's disease. 7 with multiinfarct and 1 with mixed dementia. All patients were submitted to clinical, morphological (MRI, CT) and functional (SPECT, cerebral flowmetry) studies. The severity of hypoperfusion revealed by SPECT was highly correlated with cognitive impairment in Alzheimer's dementia patients. The abnormal perfusion was mostly bilateral, in the temporal-parietal region, and involved the frontal regions only in the most severe cases. CT and especially MRI showed aspecific cortical and subcortical atrophy, most evident in the medial temporal region. In the patients with multiinfarct dementia, the hypoperfused cortical regions revealed by SPECT were sometimes related to vascular lesions proved at MRI and CT. In the patients with multiinfarct dementia, MRI showed more or less apparent white matter lesions referrable to ischemic insult, besides cortical and subcortical atrophy. MRI allows a differential diagnosis between these two cerebral pathologic conditions of aging. Cerebral flowmetry by Xenon 133 inhalation showed reduced cerebral blood flow in both dementia types. In Alzheimer patients, regional flow was reduced especially in the posterior parietal regions. In multiinfarct dementia patients, flow was more diffusely reduced and asymmetrical. Brain function imaging appears to yield useful information for the differential diagnosis in the most common dementia syndromes. Since the neuropathologic data from brain biopsy are rarely available, clinical and instrumental findings must be integrated for diagnostic and pathogenetic insights of the diseases causing cognitive impairment.

Magnetic stimulation of the spinal accessory nerve: normative data and clinical utility in an isolated stretch-induced palsy.

We report the clinical and electrophysiological findings of isolated stretch-induced accessory nerve palsy obtained by using conventional technique compared to magnetic stimulation at the base of the skull. The same methods of magnetic stimulation were applied in 10 healthy volunteers, to determine normal limits of amplitude and latency of the motor responses. The clinical features of the isolated spinal accessory nerve palsy are weakness of the sternocleidomastoid muscle and of the three portions of trapezius muscle. Most commonly reported etiologies include surgical manipulation and excision in the posterior triangle of the neck. Less frequently the cause is represented by radiation procedures, shoulder traction, penetrating, blunt or stretch injuries; this last etiology is extremely rare. The use of conventional electrophysiological methods to evaluate injuries of the nerves leaving the base of the skull is limited by the difficulty in obtaining an adequate electrical surface stimulation necessitating the use of needle electrodes. Moreover, conventional electrical stimulation often causes significant discomfort to the patient. The magnetic coli stimulation at the base of the skull is a new alternative painless technique that permits to elicit motor responses, by stimulating deeply situated nerves and, in particular, the accessory nerve, resulting as a useful electrodiagnostic tool.

[Utility of electrophysiologic study using the blink reflex and brainstem evoked potentials for the evaluation of the course of uremic polyneuropathy]. / Utilità dello studio elettrofisiologico mediante blink reflex e potenziali evocati del tronco encefalico (BAEPS), per la valutazione dell'evoluzione della polineuropatia uremica.

On the present study the authors evaluate the utility of electrophysiologic examination in uraemic polyneuropathy. A group of 19 uraemic patients in chronic dialysis underwent the Blink reflex and BAEPSs study to evaluate the alterations of nervous pathways. The results obtained were compared with those of a group of 10 healthy patients comparable for age and sex. The electrophysiologic parameters have been statistically compared with the plasma levels of vit. B12. folic acid, PTH and beta-2-microglobulin. The results show a significant difference of uremic patients compared with the healthy ones for the Blink reflex (ipsilateral and contralateral R2 responses). Also BAEPSs show significant alterations in the uraemic group (latencies of the III, V components). A statistically significantly inverse correlation is present between folic acid values and blink reflex R1 and R2 responses. Therefore our study shows the existence of a combined degeneration of central and peripheral nervous pathways in chronic uraemic patients. We believe that the decrease in folic acid concentration found in our study may be one of the causes of the beginning and then of the worsening of neurologic damage.

Computer modelling of brain cortex excitation by magnetic field pulses.

In spite of many clinical and experimental applications, the technique of transcranial magnetic stimulation still presents obscure aspects. This especially concerns safety parameters and the exact characterization of the current induced by a single magnetic pulse. The model proposed consists of an equivalent electric network derived by Maxwell's equations and applied to discretized magnetic resonance imaging of a normal subject. This model allows accurate prediction of current distribution, charge per phase and dissipated energy.

Topographic EEG analysis. Methods for graphic representation and clinical applications.

Topographic EEG analysis includes different techniques to display the spatial distribution of brain electrical activity. The correct reconstruction of the scalp potentials and the consequent inference on cortical generators is influenced by many factors. In this study we focused our attention on the topographical representation of high resolution spectral EEG parameters, the choice of the interpolation algorithms for EEG mapping and the application of a spatial filtering method to scalp potential distribution. From our results there is evidence that different approaches are needed with relation to the EEG spatial features to be detected. The actual standard procedures seem not entirely adequate and the new methods proposed can improve significantly the visual reading of the EEG and its sensitivity.

[Parkinson disease and photosensitive epilepsy]. / Maladie de Parkinson et épilepsie photosensible.

A 58 year-old man with a 4-year history of Parkinson's disease developed a myoclonic syndrome with photosensitivity. The photo-convulsive response progressively worsened when therapy with levodopa, carbidopa and biperiden was interrupted. A marked reduction of the photosensitivity was obtained with bromocriptine. This case suggests that both diseases are correlated with a multiple degenerative process of the dopaminergic inhibitory pathways.

[Therapeutic effects of taurine in epilepsy: a clinical and polyphysiographic study (author's transl)]. / Effetti terapeutici della taurina nella epilessia. Indagine clinica e polifisiografica

A study was carried out after i.v. administration of 200 mg/Kg of taurine on 37 epileptic patients in whom frequency and duration of seizures was considerable. Twenty-two subjects were given taurine for 15 consecutive days and then, once a week for a period of 6 weeks. In 5 control cases, the daily dosage wascontinued up to the 30th day; in 5 more, up to the 45th day and finally, in 5 up to the 60th day. Out of 37 patients 15 had temporal lobe epilepsy, 10 were cases of Lennox-Gastaut syndrome, 5 had generalised epilepsy, either convulsive or non-convulsive, 4 had H.H.E. syndrome and three brothers had myoclonic familial progressive epilepsy. In each group the results were similar and may be summarised as follows: I) both interictal activity and electroclinical seizures were reduced by about 30% within the first 10 days of administration; II) between the 30th and 45th day the ictal and interictal activity returned to its initial values; III) after this period, on the 60th day, values were similar to the initial ones; IV) as far as interictal activity is concerned, the same effect was found during nocturnal sleep; V) no significant changes were noticed in nocturnal sleep cycles and stages; VI) there was no apparent evidence that any phase of sleep might facilitate any improvement. Improvement was observed in about 50% of the cases (21) both physically and psychologically. The physical improvement was noticed above all in the appearence of the skin while the psychological improvement was mostly related to both attention and memory. Any pathological aspect of personality did not appear to be modified.