Clinical and surgical management of holocervical spinal cord ependymomas.

BACKGROUND: Spinal ependymomas are rare tumors of the central nervous system, and those spanning the entire cervical spine are atypical. Here, we present two unusual cases of holocervical (C1-C7) spinal ependymomas. CASE DESCRIPTION: Two patients, a 32-year-old female and a 24-year-old male presented with neck pain, motor, and sensory deficits. Sagittal MRI confirmed hypointense lesions on T1 and hyperintense regions on T2 spanning the entire cervical spine. These were accompanied by cystic cavities extending caudally into the thoracic spine and rostrally to the cervicomedullary junction. Both patients underwent gross total resection of these lesions and sustained excellent recoveries. CONCLUSION: Two holocervical cord intramedullary ependymomas were safely and effectively surgically resected without incurring significant perioperative morbidity.

Widespread white matter and conduction defects in PSEN1-related spastic paraparesis.

The mechanisms underlying presenilin 1 (PSEN1) mutation-associated spastic paraparesis (SP) are not clear. We compared diffusion and volumetric magnetic resonance measures between 3 persons with SP associated with the A431E mutation and 7 symptomatic persons with PSEN1 mutations without SP matched for symptom duration. We performed amyloid imaging and central motor and somatosensory conduction studies in 1 subject with SP. We found decreases in fractional anisotropy and increases in mean diffusivity in widespread white-matter areas including the corpus callosum, occipital, parietal, and frontal lobes in PSEN1 mutation carriers with SP. Volumetric measures were not different, and amyloid imaging showed low signal in sensorimotor cortex and other areas in a single subject with SP. Electrophysiological studies demonstrated both slowed motor and sensory conduction in the lower extremities in this same subject. Our results suggest that SP in carriers of the A431E PSEN1 mutation is a manifestation of widespread white-matter abnormalities not confined to the corticospinal tract that is at most indirectly related to the mutation's effect on amyloid precursor protein processing and amyloid deposition.

The "Cuban Epidemic Neuropathy" of the 1990s: A glimpse from inside a totalitarian disease.

During the 1990s, Cuba was struck by a rare epidemic disease. Up to 50,000 people were affected by a pathology compromising primarily the optic nerve but also peripheral nerves and even spinal cord. This is a testimony from a direct witness and participant in the initial study of the epidemics showing that in spite of claims of a "multifactorial" etiology, still in the literature, the root cause of this disease is just result of the deliberate deprivation of the most elementary economic rights by extreme Government control over a population left unable to tend to its elementary survival by itself, in spite of a thorough Government-sponsored, universally celebrated Universal Healthcare System.

Quantification and localization of EEG interictal spike activity in patients with surgically removed epileptogenic foci.

OBJECTIVE: To demonstrate if interictal spike activity was localized within the resected area in surgically treated epilepsy patients; and if there is correspondence between the degree of localization and improvement after surgery. METHODS: We analyzed long-term EEGs from 34 patients. Interictal spikes were grouped in clusters and averaged according to morphology and topography. The relative contribution of each cluster to the total number of spikes in each patient was estimated. Dipole and distributed EEG source localization of each cluster was made. The percentage of spike activity localized within the site of resection (SR) during the onset was estimated. The relationship between the percentage of activity within SR and the surgery outcome was assessed. RESULTS: Fourteen patients had 90-100% of spikes within SR, 9 had 50-89%. Most patients with more than 50% of activity localized within SR were seizure free, while the 5 patients who had all activity localized outside SR were not seizure free. CONCLUSIONS: Localization of clusters containing the largest quantity of interictal spikes during onset generally corresponded to the likely location of the epileptogenic cortex. SIGNIFICANCE: Computer-assisted EEG source localization with our methodology can be a useful adjunct for the evaluation of candidates for epilepsy surgery.

Suboccipital craniotomy for Chiari I results in evoked potential conduction changes.

BACKGROUND: Management of Chiari I is controversial, in part because there is no widely used quantitative measurement of decompression. It has been demonstrated that brainstem auditory evoked responses (BAER) and somatosensory evoked potentials (SSEP) have decreased conduction latencies after wide craniectomy. We analyzed these parameters in a suboccipital craniectomy/craniotomy procedure. METHODS: Thirteen consecutive patients underwent suboccipital decompression for treatment of symptomatic Chiari I. Craniectomy was restricted to the inferior aspect of the nuchal line, and in most cases the bone flap was replaced. Neuronal conduction was monitored continuously with median nerve somatosensory evoked potentials (M-SEP), posterior tibial nerve somatosensory evoked potentials (T-SEP), BAER, or a combination. The M-SEP N20, T-SEP P37, and BAER V latencies were recorded at four milestones - preoperatively, following craniotomy, following durotomy, and following closure. RESULTS: Five males and eight females, with average age of 9 years, were studied. Clinical improvement was noted in all 13 patients. M-SEP N20 latency decreased from a mean of 18.55 at baseline to 17.75 ms after craniotomy (P = 0.01); to 17.06 ms after durotomy (P = 0.01); and to 16.68 ms after closing (P = 0.02). T-SEP P37 latency did not change significantly. BAER V latency decreased from a mean of 6.25 ms at baseline to 6.14 ms after craniotomy (P = 0.04); to 5.98 ms after durotomy (P = 0.01); and to 5.95 ms after closing (P = 0.45). CONCLUSION: Significant improvements in conduction followed both craniectomy and durotomy. Bone replacement did not affect these results.

Intracranial current density (LORETA) differences in QEEG frequency bands between depressed and non-depressed alcoholic patients.

OBJECTIVE: To assess possible differences in intracranial source distribution of surface QEEG power between depressed and non-depressed alcoholic patients in order to find any symptom-related topographic features of physiopathologic relevance. METHODS: Low-Resolution Electromagnetic Tomography (LORETA) for the delta, theta, alpha and beta bands of EEG spectra was estimated from 38 alcoholic patients, 20 with and 18 without clinical depression, in which QEEG showed decreased slow and increased beta activity diffusely. Statistical non-parametric mapping was used to compare depressed and non-depressed groups. Measures of intracranial current density in individual patients at areas of significant differences were correlated with BDI scores. RESULTS: Patients with clinical depression showed areas of significantly lower current density than non-depressed patients in delta band at left anterior temporal, left midtemporal (including amygdala and hippocampus), and both frontopolar cortices mostly on the right; and in theta band at bilateral parietal lobe, anterior cingulate and medial frontal cortex. No differences were found at alpha and beta band. Intracranial current density in delta band at left parahippocampal, left midfrontal cortex and right frontopolar cortex was negatively correlated with BDI score. Theta band also showed negative correlations with BDI at sites of significant differences. CONCLUSIONS: Diffusely decreased delta and theta activity in the surface QEEG of alcoholic patients has a different intracranial distribution linked to the presence or not of clinical depression that seems to reveal a dysfunctional neuronal state at several specific limbic and other cortical locations that have been related to a specific clinical disorder such as depression. SIGNIFICANCE: These results provided further evidence on the effects of depression in the context of alcohol dependence, in this case decreased slow activity as a possible marker of neuronal damage secondary to alcohol toxicity, clinically expressed as depressive symptoms when present in structures that are known to be related to clinical depression.

Clinical correlates of quantitative EEG alterations in alcoholic patients.

OBJECTIVE: To evaluate the incidence and clinical correlations of abnormal QEEG features in alcoholic patients. METHODS: Quantitative EEG (frequency analysis, absolute and relative powers of the four classical bands) was assessed in 191 male alcoholic patients admitted in our facility for detoxification process. All underwent psychiatric, medical and neurological examination prior to the EEG recording, in search for specific clinical or paraclinical findings. The presence or absence of relevant clinical features was codified as nominal dichotomic variables to be related to specific QEEG features. RESULTS: Only 7 patients had normal QEEG. The most frequent alteration (81 cases) was decreased power in slow (delta and theta) bands with a concurrent increase in beta band, followed by decreased power only in slow bands (33), increase only in beta band (29), decrease in both slow and alpha bands without beta alterations (28), decrease only in alpha band (6) and others. Alterations in slow and beta bands were uncorrelated. However, a significant correlation was found between decreased power in slow bands and cortical atrophy as revealed by MRI (especially in patients with early onset of alcoholism), time elapsed from the beginning of alcoholic habits (but only in younger or early onset subjects) and in a lesser degree arterial hypertension, but neither with age nor any other clinical or psychiatric feature. On the other hand, increased power in beta band correlated mainly with the use of benzodiazepines, sensoperceptual alterations (hallucinations, illusions), clinical seizures and family history of alcoholism. The effects of those variables were strongly interrelated. CONCLUSIONS: Decreased power in slow bands in alcoholic patients may be an indicator of brain atrophy or chronic brain damage, while increase in beta band is related to medication use, family history of alcoholism, hallucinations and seizures, suggesting a state of cortical hyperexcitability. SIGNIFICANCE: This study show the relation of specific QEEG alterations to certain clinical features found in alcoholics, in a further attempt to elucidate the semiological value of those alterations in individual patients.

Características del potencial evocado visual por inversión de un patrón en sujetos normales / Evoked visual potential. Pattern by inversion stimuli in normal subjects

Se estudiaron 162 sujetos normales en los culaes se midieron la latencia de los picos N75, P100, N135 y la amplitud de P100. Todas las variables se distribuyeron de forma normal, excepto la amplitud de P100. Al realizarse el análisis estadístico no se encontraron diferencias significativas entre ambos ojos para las variables estudiadas. En cuanto al comportamiento con respecto a la edad, en ambos sexos se observó una disminución significativa de las latencias entre los 20 y 40 años. En el estudio de los resultados por sexo se observó una diferencia significativa en todas las variables, encontrándose latencias y amplitudes menores en el sexo femenino, con respecto al masculino. Los resultados obtenidos coinciden en su mayoría con los obtenidos en la literatura internacional revisada (AU)

Papel de la corteza cerebral en la función motora / Brain cortex role in the motor function

Se presenta una revisión actualizada de las evidencias clínicas, anatómicas y experimentales del papel de distintas áreas de la corteza cerebral en la realización de la actividad motora voluntaria, haciéndose especial énfasis en los datos más recientes obtenidos en seres humanos sanos mediante el empleo de técnicas no invasivas como el flujo sanguíneo cerebral y el análisis de la actividad eléctrica cerebral. Se constata que el consenso actual en el ámbito internacional es que la participación de la corteza cerebral en la actividad motora es un proceso dinámico y multilocalizado en dependencia de las características específicas de la tarea a realizar, acorde a la teoría de los órganos funcionales de Anojin

Potenciales evocados somatosensoriales subcorticales / Somatosensory evoked subcortical potentials

Se presentan los resultados del estudio de los potenciales evocados somatosensoriales de corta latencia por estimulación del nervio mediano de un grupo de sujetos sanos y en pacientes con lesiones en distintos niveles del sistema nerviosos que comprometían las vías de la sensibilidad somática

Potenciales evocados somatosensoriales subcorticales / Soatosensory evoked subcortical potentials

Se presentan los resultados del estudio de los potenciales evocados somatosensoriales de corta latencia por estimulación del nervio mediano de un grupo de sujetos sanos y en pacientes con lesiones en distintos niveles del sistema nerviosos que comprometían las vías de la sensibilidad somática

Potenciales evocados visuales por presentación de optotipos / Visual evoked potentials by presentation of optotypes

Se produce la obtención de los PEV ante la presentación de un optotipo cuadriculado en blanco y negro semejante a un tablero de ajedrez en un grupo de 10 sujetos sanos. Se describe la Morfología de los potenciales y se presentan los datos normativos correspondientes a los valores de latencia y amplitud de los componentes principales y a algunas medidas de la simetría entre los potenciales obtenidos con la estimulación de ojos distintos. Se discute la utilidad potencial de esta técnica en su aplicación al diagnóstico de afecciones de la vía visual

Potenciales evocados visuales por presentación de optotipos / Visual evoked potentials by presentation of optotypes

Se produce la obtención de los PEV ante la presentación de un optotipo cuadriculado en blanco y negro semejante a un tablero de ajedrez en un grupo de 10 sujetos sanos. Se describe la Morfología de los potenciales y se presentan los datos normativos correspondientes a los valores de latencia y amplitud de los componentes principales y a algunas medidas de la simetría entre los potenciales obtenidos con la estimulación de ojos distintos. Se discute la utilidad potencial de esta técnica en su aplicación al diagnóstico de afecciones de la vía visual (AU)

Potenciales evocados auditivos de corta latencia o potenciales de tallo cerebral. I: Métodos y resultados en una población de sujetos normales / Short latency auditory evokated potencials or brain stem potentials or brain stem potentials. I: Methods and result in a normal subject population

Se describe una técnica para el registro de los potenciales auditivos de corta latencia o potenciales evocados de tallo cerebral, presentándose los valores medios y desviaciones estándares de las latencias de los 7 componentes descritos y de las amplitudes de las ramas ascendentes y descendentes de la onda V. Se describe la influencia de los parámetros del estímulo auditivo sobre las amplitudes y latencias de los potenciales de tallo cerebral. Se observa un aumento paralelo en las latencias de todos los componentes al reducir la intensidad y la frecuencia del estímulo (AU)