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At least 649 records · Page 36Linked to original sources
PubMed2006

Recovery in a patient with locked-in syndrome.

BACKGROUND AND PURPOSE: Sildenafil citrate has been shown to enhance neurogenesis, angiogenesis, synaptogenesis, and neurological outcome by augmentation of cyclic guanosine monophosphate (cGMP) levels in animal models of ischemic stroke. Whether sildenafil citrate may be helpful for recovery in human stroke is unknown at this time. METHODS: A 41-year-old woman with locked-in syndrome due to pontine infarction began receiving 150 mg of oral sildenafil citrate daily on a compassionate use basis in August 2003 and continues treatment at this time. Magneto-encephalography (MEG) was performed at 12 and 17 months after stroke. RESULTS: No serious adverse events have occurred. Significant milestone recoveries including standing, use of both arms, talking, and full return of swallowing have occurred, particularly after nine months of treatment. The MEG showed a significantly increased amplitude in the somatosensory cortex. CONCLUSION: Daily use of high dose sildenafil citrate appears to be safe in this patient with stroke resulting in locked-in syndrome. Further studies will be required to establish safety and efficacy.

Adult↗
PubMed2000

Fatal deterioration of neurological disease after orthotopic liver transplantation for valproic acid-induced liver damage.

We describe a 12-year-old girl with an early onset neurologic disease of slow progressiveness and electro-encephalography showing epileptic activity. The girl developed fulminant liver failure 5 months after the start of valproic acid treatment. Repeated mitochondrial assays failed to prove a mitochondrial disorder, but muscle biopsies were slightly pathological. Liver histology indicated acute-on-chronic liver disease. Six weeks after a successful orthotopic liver transplantation her neurological condition deteriorated rapidly, soon leading to generalized cortical disease and death. Post-mortem brain examination showed advanced central nervous destruction. We suggest that this is a late-onset Huttenlocher variant of Alpers' syndrome, where fulminant liver failure can be triggered by valproic acid, and orthotopic liver transplantation can subsequently trigger a fatal neurologic deterioration. Our case illustrates that when a referral center receives a previously unknown patient with hepatocellular insufficiency, it might be impossible to differentiate between fulminant vs. acute-on-chronic liver failure, and the decision whether to perform a liver transplantation or not would become difficult.

Adolescent↗
PubMed1978

The psychotropic properties of estrogens.

In this review article clinical literature and experimental work from biochemistry, electro-encephalography and experimental psychology will be reported. Like the androgens and progestogens reviewed earlier, estrogens have psychotropic properties comparable to those of well-known psychotropic compounds. These are: improvement of psychological test results and increase in extraversion and decrease in neuroticism according to the Eysenck Personality Model (1964). Such effects are usually associated with the psychostimulants. The immediate effect on EEG of 4 mg estradiol valerate (single oral dose, male subjects), is a standard EEG profile similar to that of the tricyclic antidepressants. High dosages of estrogens have antidepressant properties clinically. In terms of psycho-pharmacological profiles, the estrogens seem to be a new type of psychotropic compound.

Adult↗
PubMed1976

[Transverse axial computerized tomography (EMI scan): value and indications (author's transl)].

The results of transverse axial computerized tomography in EMI scan (transverse CAT) in 2 000 examinations are reviewed. The method was shown to enlarge significantly the diagnostic possibilities in cerebral disease. A correct identification of intracranial tumour was made in 98% of 250 cases. Cerebral haemorrhage, infarction and contusional oedema could be differentiated. Various forms and extensions of cerebral oedema were visualized as never before. Postoperative changes and the course of vascular disease, tumour or hydrocephalus after shunt were demonstrated at an early stage. The indications for pneumo-encephalography have been reduced to a few very special situations. On the other hand, angiography is still of decisive value in vascular cerebral disease and should be performed before surgery in case of space-occupying lesions.

Brain↗
PubMed1975

[Computerised axial tomography of the head (E.M.I. scan). Clinical experience with a new diagnostic method for examining the brain (author's transl)].

Computerised tomography of the head is a unique radiological method with an exceptional ability in demonstrating intracranial lesions. Increasing experience will ensure this method very wide scope in the diagnosis of neurological and neurosurgical diseases; it will make conventional methods, such as angiography, pneumo-encephalography and brain scanning largely superfluous. The frequency of incorrect diagnoses is acceptable and will be further reduced with increasing experience of the method.

Astrocytoma↗
PubMed1978

[Disturbances in C.S.F. circulation after subarachnoid bleeds--a comparison of pneumoencephalographic and scintigraphic findings (author's transl)].

Haemorrhages into the subarachnoid space lead to scarlike changes in the leptomeninges in some patients. If these changes reach a certain severity, circulation of the C.S.F.. is compromised and absorption reduced. This eventually results in ventricular dilatation which, in severe cases, is clinically manifested by dementia, motor ataxia and incontinence. The early stages of the disturbance in C.S.F. circulation were examined scintigraphically in 165 patients with spontaneous traumatic or operative subarachnoid bleeding. In the presence of abnormal findings which suggested the need for C.S.F. shunting, air encephalography was carried out in addition. Special attention was paid to the demonstration of the extent and localisation of occlusions of the basal cisterns and of the cortical subarachnoid spaces. Typical scintigraphic and pneumoencephalographic findings are demonstrated and their diagnostic value compared.

Humans↗
PubMed2003

Multifocal stimulation techniques in ophthalmology -- Current knowledge and perspectives.

The purpose of this paper is to give a brief overview on the application of multifocal stimulation techniques in ophthalmology. The use of m-sequences as a stimulus sequence allows a high-resolution topographic mapping of sensory function. Outer retinal dysfunction can readily be detected with the multifocal ERG (mfERG). When the inner retinal contribution to the mfERG response is enhanced through adapting the stimulation sequence, the sensitivity of the mfERG to detect retinal dysfunction in glaucoma can be increased. Testing of the entire visual pathway with multifocal cortical evoked visual potentials is also possible and recent studies have focused on reducing interindividual variability. The use of m-sequence stimulation in magnetic encephalography offers new ways to study visual processing without the need to apply electrodes.

Electroretinography↗
PubMed2003

Biomagnetism: a new tool in sport and exercise science.

Biomagnetometry is a non-invasive technique for detecting magnetic fields associated with the electrophysiology and magnetic susceptibility of body tissues. The aims of this paper are to provide a review of the discipline of biomagnetism and its measurement using a superconducting quantum interference device (SQUID), and to discuss the potential utility of this technique in sport and exercise science. A tutorial section is presented to provide an introduction to the theory and practical application of SQUID biomagnetometry. A review of the biomagnetism literature demonstrates the variety of previous biomagnetic investigations and suggests several potential applications of biomagnetometry in sport and exercise science. A discussion of these includes an assessment of the advantages of measuring biomagnetic fields as opposed to electrical potentials, with particular reference to the improved precision and accuracy of physiological source modelling using biomagnetic data. There is evidence to suggest that SQUID biomagnetometry would provide useful (and perhaps unique) information on functional, anatomical and physiological assessments in sport and exercise science. Further investigations of biomagnetometry in this discipline should focus on three main areas: cardiology, encephalography and neurology, and body composition assessment.

Biophysical Phenomena↗
PubMed2006

Generalized head models for MEG/EEG: boundary element method beyond nested volumes.

Accurate geometrical models of the head are necessary for solving the forward and inverse problems of magneto- and electro-encephalography (MEG/EEG). Boundary element methods (BEMs) require a geometrical model describing the interfaces between different tissue types. Classically, head models with a nested volume topology have been used. In this paper, we demonstrate how this constraint can be relaxed, allowing us to model more realistic head topologies. We describe the symmetric BEM for this new model. The symmetric BEM formulation uses both potentials and currents at the interfaces as unknowns and is in general more accurate than the alternative double-layer formulation.

Algorithms↗
PubMed2006

Imaging the airways in 2006.

Imaging has traditionally been separated into two distinct disciplines: functional imaging and structural imaging. Functional imaging encompasses applications such as nuclear medicine (single photon emission computed tomography [SPECT] and positron emission tomography [PET]), autoradiography, magnetic resonance spectroscopy (MRS) and magneto-encephalography (MEG), while structural, or anatomical, imaging includes planar radiography, x-ray computed tomography (CT), and magnetic resonance imaging (MRI). However, today, the distinctions between these are blurring due to advances in software fusion and the development of multi-modality (SPECT/CT, PET/CT) scanners. New techniques such as MRI using hyperpolarized gases (3H and 129Xe) and xenon K-edge synchrotron x-ray subtraction imaging are also being developed to provide the researcher with a variety of ways to probe the airways, and the distribution of pharmaceuticals and subsequent uptake and bio-distribution. This paper reviews advances in imaging to present a contemporary view of the tools available.

Diagnostic Imaging↗
PubMed2003

Progress in imaging stroke: emerging clinical applications.

Recent years have seen major advances in the imaging of cerebrovascular disease. Although quantitative positron emission tomography (PET) has continued to be the gold standard in acquiring functional imaging data, with recent developments continuing to bear fruit, it remains a complex, costly, and not readily available technique. The emphasis in this overview is in the development of the newer magnetic resonance (MR) techniques, such as diffusion-weighted (DWI) and perfusion-weighted imaging (PWI), which allow rapid assessment of the underlying pathophysiology in acute ischaemic stroke. This is of major importance in classifying patients according to pathophysiology rather than clinical and structural imaging data, which may be essential in deciding therapy such as thrombolysis (which has proven benefit within 3-6 h of clinical onset, but can also lead to harmful haemorrhagic transformation) and/or neuroprotection, as well as patient selection in clinical trials. In conjunction with magnetic resonance angiography (MRA), DWI-PWI has been shown to improve the diagnosis and clinical management of stroke. Other novel MR techniques which have yet to reach the clinician, such as spectroscopic imaging, diffusion tensor imaging (DTI) and blood oxygenation level-dependent functional MRI (BOLD-fMRI), are currently established research tools which provide data about infarct evolution, fibre disruption and the mechanisms of stroke recovery. Electrophysiological methods including transcranial magnetic stimulation (TMS) and magneto-encephalography (MEG) will not be addressed here.

Brain Ischemia↗
PubMed2001

Clinical, biochemical and molecular genetic characteristics of 19 patients with the Sjögren-Larsson syndrome.

Sjögren-Larsson syndrome (SLS) is an autosomal recessively inherited neurocutaneous disorder caused by a deficiency of the microsomal enzyme fatty aldehyde dehydrogenase (FALDH). We report the clinical characteristics and the results of molecular studies in 19 SLS patients. Patients 1-17 show the classical triad of severe clinical abnormalities including ichthyosis, mental retardation and spasticity. Most patients were born preterm, and all patients exhibit ocular abnormalities and pruritus. Electro-encephalography shows a slow background activity, without other abnormalities. MRI of the brain shows an arrest of myelination, periventricular signal abnormalities of white matter and mild ventricular enlargement. Cerebral (1)H-MR spectroscopy reveals a characteristic, abnormal lipid peak. The degree of white matter abnormality in the MRIs and the height of the lipid peak in (1)H-MR spectra do not correlate with the severity of the neurological signs. The clinical presentation and the clinical course is strikingly similar in these patients. Patient 18 shows a mild phenotype that essentially contains the same, but less severe, clinical features. Patient 19 exhibits the typical, but very mild, dermatological and ocular abnormalities, without any clinical neurological involvement. The diagnosis of SLS was confirmed by demonstration of the enzyme defect in cultured skin fibroblasts. Furthermore, as might be predicted from the essential role of FALDH in leucotriene B(4) (LTB(4)) metabolism, elevated urinary concentrations of LTB(4) and 20-OH-LTB(4) were found in all patients studied. Molecular studies of the FALDH gene revealed eight different mutations, including three new ones: a large 26-base pair deletion (21-46del), a missense mutation (80C-->T) and an insertion mutation (487-488insA). The vast majority of SLS patients seem to be severely affected independent of their genotype.

Adolescent↗
PubMed2005

Left-hemispheric brain activity reflects formant transitions in speech sounds.

Connected speech is characterized by formant transitions whereby formant frequencies change over time. Here, using magneto-encephalography, we investigated the cortical activity in 10 participants in response to constant-formant vowels and diphthongs with formant transitions. All the stimuli elicited prominent auditory N100m responses, but the formant transitions resulted in latency modulations specific to the left hemisphere. Following the elicitation of the N100m, cortical activity shifted some 10 mm towards anterior brain areas. This late activity resembled the N400m, typically obtained with more complex utterances such as words and/or sentences. Thus, the present study demonstrates how magnetoencephalography can be used to investigate the spatiotemporal evolution in cortical activity related to the various stages of the processing of speech.

Acoustic Stimulation↗
PubMed2004

Maximum-likelihood estimation of low-rank signals for multiepoch MEG/EEG analysis.

A maximum-likelihood-based algorithm is presented for reducing the effects of spatially colored noise in evoked response magneto- and electro-encephalography data. The repeated component of the data, or signal of interest, is modeled as the mean, while the noise is modeled as the Kronecker product of a spatial and a temporal covariance matrix. The temporal covariance matrix is assumed known or estimated prior to the application of the algorithm. The spatial covariance structure is estimated as part of the maximum-likelihood procedure. The mean matrix representing the signal of interest is assumed to be low-rank due to the temporal and spatial structure of the data. The maximum-likelihood estimates of the components of the low-rank signal structure are derived in order to estimate the signal component. The relationship between this approach and principal component analysis (PCA) is explored. In contrast to prestimulus-based whitening followed by PCA, the maximum-likelihood approach does not require signal-free data for noise whitening. Consequently, the maximum-likelihood approach is much more effective with nonstationary noise and produces better quality whitening for a given data record length. The efficacy of this approach is demonstrated using simulated and real MEG data.

Algorithms↗
PubMed1982

Normal growth hormone secretion is rare after microsurgical normalization of growth hormone levels in acromegaly.

The effect of microsurgery on growth hormone (GH) secretion was studied in 34 patients with acromegaly. All patients showed enlarged sella volumes according to encephalography and macroadenomas at surgery. Preoperative GH levels were elevated in all 34 patients and 14 had concomitant hyperprolactinemia. There was a correlation between basal GH levels and sella size. Visual field defects, suprasellar extension, long duration of the disease, hyperprolactinemia and aneuploidy were noted in patients with low as well as high levels of GH preoperatively. The average reduction of GH levels in the total series was 71 +/- 21% (mean +/- SD). A notably similar reduction of GH levels was seen regardless of preoperative GH levels, concomitant hyperprolactinemia, visual field defects, size of the adenoma, invasive growth or increasing experience of the surgeon. Therefore, normal GH levels after surgery were reached mainly in patients with moderate GH increments preoperatively. GH levels were normalized by surgery in 15 patients but only four of these showed normal GH response to TRH and iota-dopa tests. Thus, only four patients (12%) fulfilled these criteria for cure of GH homeostasis.

Acromegaly↗
PubMed1980

Pituitary surgery for endocrine disorders.

The use of pituitary surgery for patients with over-production of growth hormone, corticotrophin and prolactin is reviewed. The value of specialized neuroradiological techniques is discussed including computerized tomography, air-encephalography and cavernous sinus venography. The indications for transcranial as opposed to trans-sphenoidal surgery are considered. The place of trans-sphenoid surgery in the treatment of acromegaly is emphasized and the indications for surgical treatment are reviewed. The two syndromes due to over-production of ACTH are considered--Cushing's disease and Nelson's syndrome. The increasing use of pituitary surgery for the treatment of Cushing's syndrome due to increased ACTH production is noted, but a warning is given about the small ACTH-secreting pulmonary carcinoid tumour that may closely mimic Cushing's disease. The difficulties encountered in trying to treat patients with Nelson's syndrome are stressed. It is recommended that in the rate case where total adrenalectomy is required in Cushing's disease, pituitary irradiation should be given before or shortly after adrenalectomy. The present position relating to the surgical treatment of the small prolactin-secreting pituitary tumour is reviewed. Published data and personal experience suggests that for many of these patients, treatment with bromocriptine is preferable to trans-sphenoidal surgery. Large prolactinomas usually need transfrontal surgery and X-ray therapy, sometimes followed by bromocriptine treatment. The need for steroid cover for pituitary surgery is discussed and it is suggested that a glucocorticoid with less salt-retaining action than cortisol should be used. The importance of post-operative endocrine assessment is emphasized and a convenient method suggested. The incidence of complications after transsphenoidal surgery is low, although panhypopituitarism occurred in 14% of the cases reported.

Acromegaly↗
PubMed1989

Prolactinomas presenting as primary amenorrhoea and delayed or arrested puberty: response to medical therapy.

Fourteen patients presented with arrested pubertal development associated with prolactin-secreting pituitary tumours; serum prolactin ranged from 4000-104,300 mU/l in the ten females and 920-68,000 in four males. Skull X-ray showed a markedly expanded pituitary fossa in eight patients. CT scan and/or air encephalography showed macroadenomas in nine, of whom seven had large suprasellar extensions to their tumours, yet only five had complained of headache and only two had visual field defects. All were treated with bromocriptine (7.5-60 mg/day) which lowered prolactin substantially in all and into the normal range in 11 (range less than 60-3090, median 105 mU/l). Puberty thereafter progressed spontaneously in 13, but in one patient, whose prolactin did not suppress completely, menarche could be induced only with clomiphene. Anterior pituitary function improved on bromocriptine. In seven patients with macroadenomas, tumour shrinkage into the pituitary fossa was complete and in two others incomplete shrinkage was followed by transsphenoidal hypophysectomy. Seven patients received pituitary irradiation, six after bromocriptine-induced shrinkage and one after transsphenoidal surgery. At follow-up 6 months to 10 years (median 5 years) after presentation, ten remain on bromocriptine with a suppressed serum prolactin, one has a normal prolactin after surgery, and three are off bromocriptine with residual hyperprolactinaemia (418-4680 mU/l). To date, four females have become pregnant and one male has fathered two children. Prolactinomas are an important, albeit rare, cause of arrested puberty and should therefore be sought. Most patients respond well to bromocriptine, with or without pituitary irradiation.

Adolescent↗
PubMed2005

Mechanisms of face perception in humans: a magneto- and electro-encephalographic study.

We have been studying the underlying mechanisms of face perception in humans using magneto- (MEG) and electro-encephalography (EEG) including (1) perception by viewing the static face, (2) differences in perception by viewing the eyes and whole face, (3) the face inversion effect, (4) the effect of gaze direction, (5) perception of eye motion, (6) perception of mouth motion, and (7) the interaction between auditory and visual stimuli related to the vowel sounds. In this review article, we mainly summarize our results obtained on 3, 5, and 6 above. With the presentation of both upright and inverted unfamiliar faces, the inferior temporal cortex (IT) centered on the fusiform gyrus, and the lateral temporal cortex (LT) near the superior temporal sulcus were activated simultaneously, but independently, between 140 and 200 ms post-stimulus. The right hemisphere IT and LT were both active in all subjects, and those in the left hemisphere in half of the subjects. Latencies with inverted faces relative to those with upright faces were longer in the right hemisphere, and shorter in the left hemisphere. Since the activated regions under upright and those under inverted face stimuli did not show a significant difference, we consider that differences in processing upright versus inverted faces are attributable to temporal processing differences rather than to processing of information by different brain regions. When viewing the motion of the mouth and eyes, a large clear MEG component, 1M (mean peak latency of approximately 160 ms), was elicited to both mouth and eye movement, and was generated mainly in the occipito-temporal border, at human MT/V5. The 1M to mouth movement and the 1M to eye movement showed no significant difference in amplitude or generator location. Therefore, our results indicate that human MT/V5 is active in the perception of both mouth and eye motion, and that the perception of movement of facial parts is probably processed similarly.

Adult↗