[The value of quantitative electroencephalogram analysis in the study of dementias]. / Utilidad del análisis cuantitativo del electroencefalograma en el estudio de las demencias.

INTRODUCTION: The question as to whether an electroencephalogram (EEG) needs to be carried out as a preliminary study in patients with dementia is currently the subject of some controversy. AIMS: Our aim was to determine the value of conventional and quantitative analysis of EEG recordings in the treatment of dementia. PATIENTS AND METHODS: The EEG recordings of patients diagnosed with a syndrome of dementia were analysed both visually and quantitatively (comparing them with patients with major depressive disorder). RESULTS: A total of 45 EEG traces were analysed -25 from patients with dementia and 20 with major depressive disorder-. The most significant finding was the number of abnormal recordings in each group, which was higher in the dementia group, with 19 abnormal recordings (76%) versus five in the depression group (25%). The difference was statistically significant (p = 0.001). The slow base rhythm and low voltage also differed notably between the two groups. The two groups displayed significant differences in both the frontal d and the temporal q rhythms (relative power), although the percentage was higher in patients with dementia. The posterior a rhythm was the variable with the greatest difference, and the percentage was higher in patients with depression. In absolute power, only the posterior a rhythm displayed a significant difference between the two groups, and was greater in the patients with depression. CONCLUSIONS: Performing an EEG in the initial treatment of patients with dementia is useful to distinguish it from other pathological conditions, and its quantitative analysis helps in the search for the focus.

Utilidad del análisis cuantitativo del electroencefalograma en el estudio de las demencias / The value of quantitative electroencephalogram analysis in the study of dementias

Introducción. Actualmente existe controversia acerca dela necesidad de realizar o no, como estudio inicial, un electroencefalograma(EEG) en el paciente con demencia. Objetivo. Establecer lautilidad del análisis convencional y cuantitativo del EEG en el abordajede la demencia. Pacientes y métodos. Se realizó el análisisvisual y cuantitativo de los EEG de pacientes con diagnóstico de síndromedemencial (en comparación con pacientes con trastorno depresivomayor). Resultados. Se analizaron en total 45 EEG, 25 a pacientescon demencia y 20 con trastorno depresivo mayor. Los hallazgosmás relevantes fueron el número de registros anormales encada grupo, y fue superior en el grupo de demencia, con 19 registrosanormales (76%), contra cinco en el grupo de depresión (25%), conuna diferencia estadísticamente significativa (p = 0,001). El ritmode base lento y el bajo voltaje también constituyeron diferencias significativasentre ambos grupos. Tanto el ritmo ä frontal, como el ètemporal (poder relativo) mostraron diferencias significativas entreambos grupos, y existió en mayor porcentaje en los pacientes condemencia. El ritmo áposterior fue la variable con mayor diferencia,y fue mayor el porcentaje en pacientes con depresión. En el poderabsoluto, sólo el ritmo áposterior mostró una diferencia significativaentre los dos grupos, y fue mayor en los pacientes con depresión.Conclusiones. La realización de un EEG en el abordaje inicial delos pacientes con demencia resulta de utilidad discriminativa frentea otras patologías, y el análisis cuantitativo del mismo ayuda en labúsqueda de focalización

Introduction. The question as to whether an electroencephalogram (EEG) needs to be carried out as a preliminarystudy in patients with dementia is currently the subject of some controversy. Aims. Our aim was to determine the value ofconventional and quantitative analysis of EEG recordings in the treatment of dementia. Patients and methods. The EEGrecordings of patients diagnosed with a syndrome of dementia were analysed both visually and quantitatively (comparingthem with patients with major depressive disorder). Results. A total of 45 EEG traces were analysed –25 from patients withdementia and 20 with major depressive disorder–. The most significant finding was the number of abnormal recordings ineach group, which was higher in the dementia group, with 19 abnormal recordings (76%) versus five in the depression group(25%). The difference was statistically significant (p = 0.001). The slow base rhythm and low voltage also differed notablybetween the two groups. The two groups displayed significant differences in both the frontal äand the temporal èrhythms(relative power), although the percentage was higher in patients with dementia. The posterior árhythm was the variable withthe greatest difference, and the percentage was higher in patients with depression. In absolute power, only the posterior árhythm displayed a significant difference between the two groups, and was greater in the patients with depression.Conclusions. Performing an EEG in the initial treatment of patients with dementia is useful to distinguish it from otherpathological conditions, and its quantitative analysis helps in the search for the focus

Recent developments in the quest for myoclonic epilepsy genes.

Understanding the latest advances in the molecular genetics of the epilepsies is important, as it provides a basis for comprehending the new practice of epileptology. Epilepsies have traditionally been classified and subtyped on the basis of clinical and neurophysiologic concepts. However, the complexity and variability of phenotypes and overlapping clinical features limit the resolution of phenotype-based classification and confound epilepsy nosology. Identification of tightly linked epilepsy DNA markers and discovery of epilepsy-causing mutations provide a basis for refining the classification of epilepsies. Recent discoveries regarding the genetics surrounding certain epilepsy types (including Lafora's progressive myoclonic epilepsy, the severe myoclonic epilepsy of infancy of Dravet, and idiopathic generalized epilepsies) may be the beginning of a better understanding of how rare Mendelian epilepsy genes and their genetic architecture can explain some complexities of the common epilepsies.

Epilepsia mioclónica juvenil en el cromosoma 6p12: avances clínicos y genéticos / Juvenile myoclonic epilepsy in chromosome 6p12: clinical and genetic advances

Entre las epilepsias generalizadas idiopáticas, la epilepsia mioclónica juvenil (EMJ) es la más frecuente y representa el 12-30 por ciento de todas las epilepsias del mundo occidental. La EMJ `clásica' consiste de mioclonía al despertar, crisis convulsivas de gran mal y electroencefalogramas (EEG) con polipunta-ondas de 4 a 6 Hz, que se presentan en la adolescencia. Los probandos y los miembros afectados de la familia no presentan ausencias punta-onda picnolépticas de 3 Hz. Sin embargo, el 10-30 por ciento de los pacientes presentan ausencias polipunta-onda escasas o raras. En 1988, 1995 y 1996 realizamos el mapeo genético de la EMJ `clásica' en un locus de 7 cM en el cromosoma 6p12-11, llamado EMJ1, mediante el empleo de familias de Los Ángeles y Belice. En 2001, estudiamos una familia numerosa de Belice y 21 familias nuevas de Los Ángeles y de Ciudad de México, con la ayuda de un mapa físico basado en recursos BAC/PAC y seis repeticiones dinucleotídicas, para reducir el cromosoma EMJ1 a un intervalo entre los marcadores D6S272 y D6S1573. En 2002, hallamos mioclonín, gen putativo de la EMJ típica en el cromosoma 6p12. En el congreso revelaremos la identidad del gen mioclonín, su función putativa y discutiremos la significación de este descubrimiento en la población con EMJ en general (AU)

Transient hemifacial spasm associated with subarachnoid brainstem cysticercosis: a case report.

The authors present the case of a 69 year old woman who developed bladder incontinence and confusion. A CT scan showed severe hydrocephalus and calcifications, prompting a ventriculoperitoneal shunt placement. On the day after operation the patient presented left hemifacial spasm. MR revealed a subarachnoid cysticercus rostral to the pons, and surgical excision was proposed. She refused surgery and was placed on prednisone. Brainstem auditory responses were absent on the left side 2 months after shunting and were still abnormal 53 months later. The hemifacial spasm disappeared 3 months after shunt placement and has not recurred in 5 years of follow-up.

[Peripheral neuropathy caused by acute arsenic poisoning]. / Neuropatía periférica por intoxicación aguda con arsénico.

Although peripheral neuropathy is a fairly common finding in chronic arsenic poisoning, little is known about the acute effects of this metal on peripheral nerves. This report shows clinical and electrophysiological findings in a patient who developed peripheral neuropathy only three days after a high-dose ingestion of this metal due to a failed suicide attempt. We speculate that peripheral nerves and some cranial nerves can show not only clinical but also subclinical involvement that can only be detected by neurophysiological studies.

[Creutzfeldt-Jakob disease. Clinical, electrophysiological and histopathological correlations]. / La enfermedad de Creutzfeldt-Jakob. Correlación clínica, electrofisiológica e histopatológica.

Creutzfeldt-Jakob disease (CJD) is one of a small group of the so-called spongiform encephalopathies. It is a rare transmissible disorder which is characterized by progressive and irreversible neurological damage. There are few reports where clinical manifestations are correlated with neurophysiologic and histopathologic findings. The present paper includes three cases of CJD where alterations in evoked potentials and brain mapping studies gave valuable information, especially in those where the clinical picture and the electroencephalogram were non-specific, we conclude that these alterations suggest that the classic histopathological changes in C-J disease involves both cortical and subcortical structures.

Clinical, electrophysiologic and neuroimaging findings in Wernicke's syndrome.

Wernicke's encephalopathy is a disease that when not diagnosed in time, can lead to severe CNS damage and death. It is characterized by specific clinical and radiologic findings; however, there are few reports dealing with the usefulness of neurophysiologic studies in this syndrome. We present a patient with Wernicke's encephalopathy, diagnosed postmortem on autopsy, in whom the neurophysiologic studies showed abnormalities in all the different pathways tested. This suggests that EEG and evoked potentials may be useful tools in the diagnostic workup of this entity. We propose performing these tests when this syndrome is being considered.

Status epilepticus within the Lennox-Gastaut syndrome: clinical characteristics and management.

This report describes 2 cases, 7 and 8 years of age, with the Lennox-Gastaut Syndrome and status epilepticus. Both cases responded favorably, clinically and in their EEGs, to continuous therapeutic control with clonazepam, and remained under control with valproic acid.