RESUMEN
To clarify the physiological significance of task-related change of the regional electroencephalogram (EEG) rhythm, we quantitatively evaluated the correlation between regional cerebral blood flow (rCBF) and EEG power. Eight subjects underwent H2 15O positron emission tomography scans simultaneously with EEG recording during the following tasks: rest condition with eyes closed and open, self-paced movements of the right and left thumb and right ankle. EEG signals were recorded from the occipital and bilateral sensorimotor areas. Cortical activation associated with EEG rhythm generation was studied by the correlation between rCBF and EEG power. There were significant negative correlations between the sensorimotor EEG rhythm at 10-20 Hz on each side and the ipsilateral sensorimotor rCBF and between the occipital EEG rhythm at 10-20 Hz and the occipital rCBF. The occipital EEG rhythm showed a positive correlation with the bilateral medial prefrontal rCBF, while the right sensorimotor EEG rhythm showed a positive correlation with the left prefrontal rCBF. In conclusion, decrease in the regional EEG rhythm at 10-20 Hz might represent the neuronal activation of the cortex underlying the electrodes, at least for the visual and sensorimotor areas. The neural network including the prefrontal cortex could play an important role to generate the EEG rhythm.
Asunto(s)
Nivel de Alerta/fisiología , Corteza Cerebral/irrigación sanguínea , Electroencefalografía , Procesamiento de Imagen Asistido por Computador , Imagenología Tridimensional , Actividad Motora/fisiología , Tomografía de Emisión de Positrones , Procesamiento de Señales Asistido por Computador , Transmisión Sináptica/fisiología , Adulto , Mapeo Encefálico , Corteza Cerebral/diagnóstico por imagen , Corteza Cerebral/fisiología , Dominancia Cerebral/fisiología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Corteza Motora/irrigación sanguínea , Corteza Motora/diagnóstico por imagen , Corteza Motora/fisiología , Red Nerviosa/irrigación sanguínea , Red Nerviosa/diagnóstico por imagen , Red Nerviosa/fisiología , Neuronas/fisiología , Lóbulo Occipital/irrigación sanguínea , Lóbulo Occipital/diagnóstico por imagen , Lóbulo Occipital/fisiología , Corteza Prefrontal/irrigación sanguínea , Corteza Prefrontal/diagnóstico por imagen , Corteza Prefrontal/fisiología , Valores de Referencia , Flujo Sanguíneo Regional/fisiología , Corteza Somatosensorial/irrigación sanguínea , Corteza Somatosensorial/diagnóstico por imagen , Corteza Somatosensorial/fisiología , Estadística como AsuntoRESUMEN
Twenty-one single oral doses of 1-octanol were given to patients with essential tremor (ET) in an open-label dose-escalation study. The drug was well tolerated up to 64 mg/kg. The main side effect was an unusual taste. No overt intoxication was seen. There was evidence for efficacy, with a significant reduction in tremor amplitude as measured by accelerometry and handwriting that was maximal at 2 hours. Higher doses may produce more sustained benefit.
Asunto(s)
1-Octanol/administración & dosificación , Drogas en Investigación/administración & dosificación , Temblor Esencial/tratamiento farmacológico , 1-Octanol/uso terapéutico , Adulto , Anciano , Anciano de 80 o más Años , Drogas en Investigación/uso terapéutico , Humanos , Persona de Mediana EdadRESUMEN
1-Octanol (an 8-C alcohol currently used as a food-flavoring agent) is known to inhibit tremor in essential tremor (ET) animal models at a much lower dose than ethyl alcohol. The authors conducted a randomized, placebo-controlled pilot trial of a single oral dose of 1 mg/kg of 1-octanol in 12 patients with ET. No significant side effects or signs of intoxication were observed. 1-Octanol significantly decreased tremor amplitude for up to 90 minutes. The results suggest 1-octanol as a well-tolerated and safe potential treatment for ET. Further trials are warranted.
Asunto(s)
1-Octanol/uso terapéutico , Temblor Esencial/tratamiento farmacológico , 1-Octanol/efectos adversos , Adulto , Anciano , Técnicas de Diagnóstico Neurológico/instrumentación , Temblor Esencial/diagnóstico , Femenino , Humanos , Masculino , Persona de Mediana Edad , Proyectos Piloto , Seguridad , Resultado del TratamientoRESUMEN
Cerebellar degeneration has been associated with gluten sensitivity and celiac disease. Patients with celiac disease may have neuropathy and antibodies to gangliosides. The authors investigated the presence of antiganglioside antibodies in 22 patients with hereditary and nonhereditary ataxia and found 64% reactive in a novel agglutination test.
Asunto(s)
Autoanticuerpos/inmunología , Ataxia Cerebelosa/inmunología , Gangliósidos/inmunología , Degeneraciones Espinocerebelosas/inmunología , Anciano , Enfermedades Autoinmunes del Sistema Nervioso/inmunología , Ataxia Cerebelosa/genética , Femenino , Humanos , Masculino , Persona de Mediana Edad , Atrofia de Múltiples Sistemas/genética , Atrofia de Múltiples Sistemas/inmunología , Degeneraciones Espinocerebelosas/genéticaRESUMEN
Functional imaging studies of the cerebellum have mostly investigated motor performance or have been limited to the anterior lobe and therefore the somatosensory representations in the human cerebellum have not been fully demonstrated. We used fMRI of the entire cerebellum during tactile stimulation of the hand and foot in six normal subjects. Our results demonstrate that the tactile projections to the cerebellum in humans are represented in both the anterior and posterior lobes. in agreement with previous functional imaging studies, our results show a large-scale, between-limb somatotopy comparable to that shown in early animal studies.
Asunto(s)
Mapeo Encefálico , Cerebelo/fisiología , Tacto/fisiología , Adulto , Mano , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Estimulación Física , Corteza Somatosensorial/fisiologíaRESUMEN
Gluten sensitivity, with or without classical celiac disease symptoms and intestinal pathology, has been suggested as a potentially treatable cause of sporadic cerebellar ataxia. Here, we investigated the prevalence of abnormally high serum immunoglobulin A (IgA) and IgG anti-gliadin antibody titers and typical human lymphocyte antigen (HLA) genotypes in 50 patients presenting with cerebellar ataxia who were tested for molecularly characterized hereditary ataxias. A high prevalence of gluten sensitivity was found in patients with sporadic (7/26; 27%) and autosomal dominant (9/24; 37%) ataxias, including patients with known ataxia genotypes indicating a hitherto unrecognized association between hereditary ataxias and gluten sensitivity. Further studies are needed to determine whether gluten sensitivity contributes to cerebellar degeneration in patients with hereditary cerebellar ataxia. Patients with hereditary ataxia (including asymptomatic patients with known ataxia genotype) should be considered for screening for gluten sensitivity and gluten-free diet trials.
Asunto(s)
Ataxia Cerebelosa/genética , Ataxia Cerebelosa/inmunología , Hipersensibilidad a los Alimentos/inmunología , Glútenes/efectos adversos , Glútenes/inmunología , Adolescente , Adulto , Anciano , Ensayo de Inmunoadsorción Enzimática , Femenino , Humanos , Masculino , Persona de Mediana EdadRESUMEN
Intersensory temporal synchrony is an ubiquitous sensory attribute that has proven to be critical for binding multisensory inputs, sometimes erroneously leading to dramatic perceptual illusions. However, little is known about how the brain detects temporal synchrony between multimodal sensory inputs. We used positron emission tomography to demonstrate that detecting auditory-visual stimulus onset asynchrony activates a large-scale neural network of insular, posterior parietal, prefrontal, and cerebellar areas with the highest and task-specific activity localized to the right insula. Interregional covariance analysis further showed significant task-related functional interactions between the insula, the posterior thalamus, and superior colliculus. Based on these results and the available electrophysiological and anatomical connectivity data in animals, we propose that the insula, via its known short-latency connections with the tectal system, mediates temporally defined auditory-visual interaction at an early stage of cortical processing permitting phenomena such as the ventriloquist and the McGurk illusions.
Asunto(s)
Estimulación Acústica , Corteza Cerebral/fisiología , Estimulación Luminosa , Tiempo de Reacción/fisiología , Tomografía Computarizada de Emisión , Adulto , Conducta/fisiología , Mapeo Encefálico , Cerebelo/diagnóstico por imagen , Cerebelo/fisiología , Corteza Cerebral/diagnóstico por imagen , Femenino , Humanos , Ilusiones/fisiología , Aumento de la Imagen , Masculino , Persona de Mediana Edad , Red Nerviosa/diagnóstico por imagen , Red Nerviosa/fisiología , Lóbulo Parietal/diagnóstico por imagen , Lóbulo Parietal/fisiología , Corteza Prefrontal/diagnóstico por imagen , Corteza Prefrontal/fisiología , Radiografía , Colículos Superiores/diagnóstico por imagen , Colículos Superiores/fisiología , Tálamo/diagnóstico por imagen , Tálamo/fisiologíaRESUMEN
Long-term deprivation of visual input for several days or weeks leads to marked changes in the excitability and function of the occipital cortex. The time course of these changes is poorly understood. In this study, we addressed the question whether a short period of light deprivation (minutes to a few hours) can elicit such changes in humans. Noninvasive transcranial magnetic stimulation (TMS) of the human occipital cortex can evoke the perception of flashes or spots of light (phosphenes). To assess changes in visual cortex excitability following light deprivation, we measured the minimum intensity of stimulation required to elicit phosphenes (phosphene threshold) and the number of phosphenes elicited by different TMS stimulus intensities (stimulus-response curves). A reduced phosphene threshold was detected 45 min after the onset of light deprivation and persisted for the entire deprivation period (180 min). Following re-exposure to light, phosphene thresholds returned to predeprivation values over 120 min. Stimulus-response curves were significantly enhanced in association with this intervention. In a second experiment, we studied the effects of light deprivation on functional magnetic resonance imaging (fMRI) signals elicited by photic stimulation. fMRI results showed increased visual cortex activation after 60 min of light deprivation that persisted following 30 min of re-exposure to light. Our results demonstrated a substantial increase in visual cortex excitability. These changes may underlie behavioral gains reported in humans and animals associated with light deprivation.
Asunto(s)
Fosfenos/fisiología , Corteza Visual/fisiología , Adulto , Oscuridad , Estimulación Eléctrica , Femenino , Humanos , Imagen por Resonancia Magnética , Magnetismo , Masculino , Estimulación Luminosa , Umbral Sensorial/fisiologíaRESUMEN
Although the importance of the posterior parietal and prefrontal regions in spatial localization of visual stimuli is well established, their role in auditory space perception is less clear. Using positron emission tomography (PET) during auditory and visual spatial localization in the same subjects, modality-specific areas were identified in the superior parietal lobule, middle temporal and lateral prefrontal cortices. These findings suggest that, similar to the visual system, the hierarchical organization of the auditory system extends beyond the temporal lobe to include areas in the posterior parietal and prefrontal regions specialized in auditory spatial processing. Our results may explain the dissociation of visual and auditory spatial localization deficits following lesions involving these regions.
Asunto(s)
Mapeo Encefálico , Lóbulo Frontal/fisiología , Lóbulo Parietal/fisiología , Desempeño Psicomotor/fisiología , Localización de Sonidos/fisiología , Percepción Visual/fisiología , Adulto , Corteza Auditiva/fisiología , Femenino , Humanos , Masculino , Corteza Prefrontal/fisiología , Percepción Espacial/fisiología , Lóbulo Temporal/fisiología , Tomografía Computarizada de EmisiónRESUMEN
To learn more about human auditory spatial processing, we used positron emission tomography (PET) to measure regional cerebral blood flow in human volunteers engaged in sound localization tasks. Spectral and binaural cues of localized sound were reproduced by a sound system and delivered via headphones. During localization tasks, subjects activated inferior parietal lobules (IPL) bilaterally. In a second experiment, matched in design to the first, subjects made non-spatial auditory discriminations based on frequency, activating the IPL bilaterally with left hemispheric predominance. A between-study comparison revealed that the right IPL was significantly more activated during the sound localization task compared with the feature discrimination task, suggesting a preferential role for the right IPL in auditory spatial processing.
Asunto(s)
Mapeo Encefálico , Encéfalo/fisiología , Circulación Cerebrovascular , Desempeño Psicomotor/fisiología , Localización de Sonidos/fisiología , Adulto , Encéfalo/irrigación sanguínea , Encéfalo/diagnóstico por imagen , Discriminación en Psicología , Electrooculografía , Humanos , Lóbulo Parietal/fisiología , Tomografía Computarizada de Emisión/métodosRESUMEN
L-Asparaginase is the major induction-phase agent for treatment of acute lymphoblastic leukemia (ALL) and an important adjuvant in treatment of non-Hodgkin's lymphoma (NHL). However, L-asparaginase-induced disturbances of clotting homeostasis may result in thrombosis or hemorrhage. Thrombotic occlusion of small cerebral veins has been reported in patients with ALL treated with this agent, but have not been described in NHL patients or those treated with the long-acting synthetic congener, pegaspargase. We report a 16-year-old boy with NHL who developed a focal motor seizure 15 min after receiving intravenous pegaspargase. MRI of the brain demonstrated multiple cortical and subcortical lesions that most likely represented focal brain edema due to thrombotic venous occlusion, which improved remarkably within 3 days and completely resolved within 3 weeks without specific intervention or permanent clinical consequences. This process must be considered when such changes are detected in NHL patients.
Asunto(s)
Antineoplásicos/efectos adversos , Asparaginasa/efectos adversos , Edema Encefálico/inducido químicamente , Embolia y Trombosis Intracraneal/inducido químicamente , Imagen por Resonancia Magnética , Polietilenglicoles/efectos adversos , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamiento farmacológico , Adolescente , Antineoplásicos/administración & dosificación , Asparaginasa/administración & dosificación , Encéfalo/patología , Edema Encefálico/diagnóstico , Estudios de Seguimiento , Humanos , Embolia y Trombosis Intracraneal/diagnóstico , Masculino , Examen Neurológico/efectos de los fármacos , Polietilenglicoles/administración & dosificación , Inducción de Remisión , Remisión EspontáneaRESUMEN
We studied the admission rate, risk factors, neurological complications and sequelae of heat stroke (HS) during the 1995 heat wave in Madison, Wisconsin. HS was epidemic in 1995 (2.3 cases/1000 admissions), compared to the ten-fold lower endemic rate in 1994 (0.2/ 1000). There were 11 cases of HS, 9 males and 2 females. Contributing factors were athletic events (2), working outdoors (3) and indoor activity with malfunctioning air-conditioning (6). Medical conditions contributing to poor temperature regulation included schizophrenia with neuroleptic treatment (2), amyotrophic lateral sclerosis receiving nortriptiline (1), multiple sclerosis (1), attention deficit disorder (1), cystic fibrosis (1) and alcoholism (1). Acute neurological complications occurred in all patients on presentation including coma (8/11.73%), stupor (2/ 11.18%) and seizures (1/11.9%). Two patients (1856) had persistent neurological sequelae in the form of a pan-cerebellar syndrome while the remaining 9 recovered fully. Importantly, avoidable factors contributed to all of the patients with underlying diseases. These patients are particularly at risk and should take adequate precautions during summer months.
Asunto(s)
Encefalopatías/epidemiología , Brotes de Enfermedades , Agotamiento por Calor/epidemiología , Adolescente , Adulto , Anciano , Encefalopatías/etiología , Niño , Preescolar , Femenino , Agotamiento por Calor/complicaciones , Humanos , Masculino , Persona de Mediana Edad , Admisión del Paciente/estadística & datos numéricos , Factores de Riesgo , Wisconsin/epidemiologíaRESUMEN
The inhibitory action of botulinum toxin is not confined to the neuromuscular junction. The toxin has long been known to block all the autonomic cholinergic fibers, including the major secretomotor parasympathetic fibers to salivary glands. The parotids are the largest of the salivary glands and their selective chemodenervation with botulinum toxin A is likely to result in substantial reduction of saliva production. Injection of the parotid glands with botulinum toxin is proposed as an new treatment for sialorrhea in patients with amyotrophic lateral sclerosis and other neurological diseases.
Asunto(s)
Esclerosis Amiotrófica Lateral/tratamiento farmacológico , Esclerosis Amiotrófica Lateral/fisiopatología , Toxinas Botulínicas Tipo A/uso terapéutico , Glándula Parótida , Sialorrea/fisiopatología , Toxinas Botulínicas Tipo A/administración & dosificación , Toxinas Botulínicas Tipo A/efectos adversos , Humanos , Modelos NeurológicosRESUMEN
The inhibitory action of botulinum toxin is not limited to the neuromuscular junction. The toxin also blocks the autonomic cholinergic fibres, including the sympathetic fibres to sweat glands. We have previously demonstrated that the toxin produces localized anhidrosis. To determine the dosage, pattern and duration of the anhidrotic effect of botulinum toxin and to test the efficacy of axillary injections, we further studied seven healthy volunteers. Two individuals had subcutaneous injections of botulinum toxin (20 mouse units, Dysport-Porton Products) in the dorsum of the hand. Five healthy volunteers had 15-50U of botulinum toxin A (Botox) injected in one axilla. A circular area of complete anhidrosis on the dorsum of the hand was evident on day 2 and persisted for 11 months. By day 3, two of the axillae (injected with 50 U each) were totally dry and in one (injected with 30 U) the sweating was substantially reduced. The effect persisted for 6-8 months before wearing off. No effect was appreciated in two axillae (injected with 15 and 20 U). No significant side-effects were encountered. Subcutaneous injections of botulinum toxin causes chemodenervation of the sweat glands. In normal individuals axillary sweating can be abolished by 50 U of botulinum toxin A (Botox). The results offer a possible novel treatment for severe cases of axillary hyperhidrosis.
Asunto(s)
Toxinas Botulínicas Tipo A/uso terapéutico , Hiperhidrosis/terapia , Adulto , Anciano , Axila , Humanos , Inyecciones Subcutáneas , Masculino , Persona de Mediana EdadRESUMEN
We report on a patient with systemic sarcoidosis who was presented with myelopathy and backache. Plain spinal films were normal, CT scan showed sclerotic lesions within the vertebrae. MRI showed more extensive involvement of the spine with multiple vertebral lesions which were hypointense on both T1W1 and T2W1 and did not enhance with gadolinium. MRI also showed high signal lesions within the cervical and lumbar spinal cord on T2-weighted images (T2W1) which were isointense on T1-weighted images (T1W1) and did not enhance. Vertebral biopsy results were consistent with the diagnosis of sarcoidosis. MRI is very sensitive in detecting sarcoidosis of bone but non-specific and other types of sclerotic or lytic bone lesions (notably metastases) need to be excluded.