Cognition and brain function in elderly Tai Chi practitioners: A case-control study

OBJECTIVE

To compare cognition and brain function in elderly Tai Chi and Water Aerobics practitioners.

METHODS

Eight Tai Chi (TC) and 8 Water Aerobics (WA) practitioners matched by gender, education and age underwent neuropsychological and fMRI scan during attention (Stroop Word Color Task) and working memory (N Back) tasks.

RESULTS

Groups were similar for demographic and cognitive variables. Besides anxiety (smaller in TC group), there were no differences between groups in neuropsychological variables. During the Stroop Word Color Task, TC group had smaller brain activation in the right intracalcarine cortex, lateral occipital cortex, and occipital pole, than WA. During N back, TC group presented smaller brain activation in the right frontal pole and superior frontal gyrus.

CONCLUSION

Despite the small number of participants in this preliminary study, both groups had similar cognitive performance, however the Tai Chi group required less brain activation to perform the attention and memory tasks, therefore they may have a more efficient cognitive performance than Water Aerobics group.

Effects of a 7-Day Meditation Retreat on the Brain Function of Meditators and Non-Meditators During an Attention Task

Meditation as a cognitive enhancement technique is of growing interest in the field of health and research on brain function. The Stroop Word-Color Task (SWCT) has been adapted for neuroimaging studies as an interesting paradigm for the understanding of cognitive control mechanisms. Performance in the SWCT requires both attention and impulse control, which is trained in meditation practices. We presented SWCT inside the MRI equipment to measure the performance of meditators compared with non-meditators before and after a meditation retreat. The aim of this study was to evaluate the effects of a 7-day Zen intensive meditation training (a retreat) on meditators and non-meditators in this task on performance level and neural mechanisms. Nineteen meditators and 14 non-meditators were scanned before and after a 7-day Zen meditation retreat. No significant differences were found between meditators and non-meditators in the number of the correct responses and response time (RT) during SWCT before and after the retreat. Probably, due to meditators training in attention, their brain activity in the contrast incongruent > neutral during the SWCT in the anterior cingulate, ventromedial prefrontal cortex/anterior cingulate, caudate/putamen/pallidum/temporal lobe (center), insula/putamen/temporal lobe (right) and posterior cingulate before the retreat, were reduced compared with non-meditators. After the meditation retreat, non-meditators had reduced activation in these regions, becoming similar to meditators before the retreat. This result could be interpreted as an increase in the brain efficiency of non-meditators (less brain activation in attention-related regions and same behavioral response) promoted by their intensive training in meditation in only 7 days. On the other hand, meditators showed an increase in brain activation in these regions after the same training. Intensive meditation training (retreat) presented distinct effects on the attention-related regions in meditators and non-meditators probably due to differences in expertise, attention processing as well as neuroplasticity.

Machado-Joseph disease in Brazil: from the first descriptions to the emergence as the most common spinocerebellar ataxia

Machado-Joseph disease is an autosomal dominant inherited disorder of Azorean ancestry firstly described in 1972. Since then, several Brazilian researchers have studied clinical and genetic issues related to the disease. Nowadays, Machado-Joseph disease is considered the most common spinocerebellar ataxia worldwide. Machado-Joseph disease still has no specific therapy to arrest progression, but the unclear pathophysiological mechanism, features related to genetic characteristics, phenotype variability, apparently global involvement of the nervous system in the disease and the therapeutic challenges continue to attract investigators in the field of spinocerebellar ataxias. Brazilian researchers have distinguished themselves in the ongoing investigation seeking new knowledge about Machado-Joseph disease.

Brain imaging analysis can identify participants under regular mental training

Multivariate pattern recognition approaches have become a prominent tool in neuroimaging data analysis. These methods enable the classification of groups of participants (e.g. controls and patients) on the basis of subtly different patterns across the whole brain. This study demonstrates that these methods can be used, in combination with automated morphometric analysis of structural MRI, to determine with great accuracy whether a single subject has been engaged in regular mental training or not. The proposed approach allowed us to identify with 94.87% accuracy (p<0.001) if a given participant is a regular meditator (from a sample of 19 regular meditators and 20 non-meditators). Neuroimaging has been a relevant tool for diagnosing neurological and psychiatric impairments. This study may suggest a novel step forward: the emergence of a new field in brain imaging applications, in which participants could be identified based on their mental experience.

Pesquisas em cérebro e Práticas Contemplativas

Introdução: Nos últimos anos tem havido um crescente interesse na investigação dos efeitos práticas de meditação na saúde mental e física. De alguma maneira, as habilidades treinadas durante as práticas meditativas, como o treinamento da atenção focada em um objeto específico, ou a monitoração dos padrões de pensamentos e emoções age modificando o funcionamento e a estrutura cerebrais. Recentemente, trabalhos na área de neuroimagem tem ajudado a elucidar possíveis mecanismo de ação das práticas meditativas no cérebro. Objetivo: revisar na literatura os estudos mais recentes sobre os efeitos da prática de meditação no cérebro e apresentar resultados de um protocolo com ressonância magnética funcional (fMRI) desenvolvido no Instituto do Cérebro do Hospital Israelita Albert Einstein (InCe-HIAE) sobre os efeitos da meditação na atenção. Método: revisão sobre estudos de neuroimagem funcional e estrutural e avaliação por fMRI de 39 sujeitos, 20 meditadores que realizam a prática há pelo menos 3 anos, por 3 vezes por semana e 20 sujeitos inexperientes em meditação. Resultados: estudos recentes têm mostrado alterações funcionais resultantes da prática de meditação, na atividade cerebral, bem como na estrutura do cérebro, como a espessura de áreas corticais. Nossos resultados preliminares corroboram com estes dados, mostrando que sujeitos que praticam meditação regularmente precisam recrutar menos áreas cerebrais, em especial frontais, do que pessoas inexperientes em meditação para ter o mesmo desempenho em uma tarefa atencional (o Stroop Word-Color Task). Conclusão: a prática de meditação pode trazer mudanças não apenas psicológicas, como mostram boa parte dos estudos, mas também modificações na fisiologia e anatomia cerebrais. Nosso estudo preliminar no InCe-HIAE indica que pessoas que praticam meditação regularmente podem apresentar um cérebro mais eficiente no desempenho de uma tarefa de atenção.

Meditation training increases brain efficiency in an attention task

Meditation is a mental training, which involves attention and the ability to maintain focus on a particular object. In this study we have applied a specific attentional task to simply measure the performance of the participants with different levels of meditation experience, rather than evaluating meditation practice per se or task performance during meditation. Our objective was to evaluate the performance of regular meditators and non-meditators during an fMRI adapted Stroop Word-Colour Task (SWCT), which requires attention and impulse control, using a block design paradigm. We selected 20 right-handed regular meditators and 19 non-meditators matched for age, years of education and gender. Participants had to choose the colour (red, blue or green) of single words presented visually in three conditions: congruent, neutral and incongruent. Non-meditators showed greater activity than meditators in the right medial frontal, middle temporal, precentral and postcentral gyri and the lentiform nucleus during the incongruent conditions. No regions were more activated in meditators relative to non-meditators in the same comparison. Non-meditators showed an increased pattern of brain activation relative to regular meditators under the same behavioural performance level. This suggests that meditation training improves efficiency, possibly via improved sustained attention and impulse control.

Frequency of the different mutations causing spinocerebellar ataxia (SCA1, SCA2, MJD/SCA3 and DRPLA) in a large group of Brazilian patients

Spinocerebellar ataxia type 1 (SCA1), spinocerebellar ataxia type 2 (SCA2) and Machado-Joseph disease or spinocerebellar ataxia type 3 (MJD/SCA3) are three distinctive forms of autosomal dominant spinocerebellar ataxia (SCA) caused by expansions of an unstable CAG repeat localized in the coding region of the causative genes. Another related disease, dentatorubropallidoluysian atrophy (DRPLA) is also caused by an unstable triplet repeat and can present as SCA in late onset patients. We investigated the frequency of the SCA1, SCA2, MJD/SCA3 and DRPLA mutations in 328 Brazilian patients with SCA, belonging to 90 unrelated families with various patterns of inheritance and originating in different geographic regions of Brazil. We found mutations in 35 families (39%), 32 of them with a clear autosomal dominant inheritance. The frequency of the SCA1 mutation was 3% of all patients; and 6% in the dominantly inherited SCAs. We identified the SCA2 mutation in 6% of all families and in 9% of the families with autosomal dominant inheritance. The MJD/SCA3 mutation was detected in 30% of all patients; and in the 44% of the dominantly inherited cases. We found no DRPLA mutation. In addition, we observed variability in the frequency of the different mutations according to geographic origin of the patients, which is probably related to the distinct colonization of different parts of Brazil. These results suggest that SCA may be occasionally caused by the SCA1 and SCA2 mutations in the Brazilian population, and that the MJD/SCA3 mutation is the most common cause of dominantly inherited SCA in Brazil.

Limits of clinical assessment in the accurate diagnosis of Machado-Joseph disease

BACKGROUND

Machado-Joseph disease (MJD) is a type of autosomal dominant spinocerebellar ataxia for which molecular diagnosis is available. We identified 4 families segregating the MJD mutation in which no unequivocal clinical diagnosis could be established prior to molecular testing. Ethnic background, clinical, and molecular characteristics of 19 individuals carrying the MJD mutation in these 4 families were compared with a group of 32 Portuguese families who were clinically diagnosed as having MJD and were found to carry the MJD mutation.

RESULTS

Several factors seemed to have an impact in the accuracy of the clinical diagnosis, such as ethnic origin; the number of affected individuals available for examination in each family; the absence of patients showing specific clinical features, such as extrapyramidal signs; and the size of the expanded CAG repeat in the MJD gene.

CONCLUSION

Since the recognition of MJD based solely on clinical grounds might sometimes be misleading, a search for the MJD mutation should be performed in patients with a clinical diagnosis of spinocerebellar degeneration.

A familial factor independent of CAG repeat length influences age at onset of Machado-Joseph disease

Machado-Joseph disease (MJD) is a late-onset, progressive, neurodegenerative disorder caused by the expansion of an unstable trinucleotide (CAG) repeat sequence in a novel gene (MJD1) on chromosome 14. Previous studies showed that age at onset is negatively correlated with the number of CAG repeat units, but only part of the variation in onset age is explained by CAG repeat length. Ages at onset and CAG repeat lengths of 136 MJD patients from 23 kindreds of Portuguese descent were analyzed, to determine whether familial factors independent of CAG repeat length modulate age at onset of MJD. Correlation among sibs for onset age adjusted for CAG repeat length was .43, which indicates that an environmental or genetic factor common to sibs influences onset age. Positive correlations were also observed for avuncular (r = .22) and first-cousin pairs (r = .28), which supports the hypothesis that a genetic factor is influencing age at onset. Commingling analysis of onset ages adjusted for CAG repeat length identified three distributions in this population of affected individuals. Further studies of a much larger sample are needed to determine whether these distributions represent the influence of a genetic or environmental factor.

Correlation between CAG repeat length and clinical features in Machado-Joseph disease

Machado-Joseph disease (MJD) is associated with the expansion of a CAG trinucleotide repeat in a novel gene on 14q32.1. We confirmed the presence of this expansion in 156 MJD patients from 33 families of different geographic origins: 15 Portuguese Azorean, 2 Brazilian, and 16 North American of Portuguese Azorean descent. Normal chromosomes contain between 12 and 37 CAG repeats in the MJD gene, whereas MJD gene carriers have alleles within the expanded range of 62-84 CAG units. The distribution of expanded alleles and the gap between normal and expanded allele sizes is either inconsistent with a premutation hypothesis or most (if not all) of the alleles we studied descend from a common ancestor. There is a strong correlation between the expanded repeat size and the age at onset of the disease as well as the clinical presentation. There is mild instability of the CAG tract length with transmission of the expanded alleles; both increase and decrease in size between parents and progeny occur, with larger variations in male than in female transmissions. Together, these effects can partly explain the variability of age at onset and of phenotypic features in MJD; however, other modifying factors must exist.

Machado Joseph disease maps to the same region of chromosome 14 as the spinocerebellar ataxia type 3 locus

Machado Joseph disease (MJD) is an autosomal dominantly inherited neuro-degenerative disorder primarily affecting the motor system. It can be divided into three phenotypes based on the variable combination of a range of clinical symptoms including pyramidal and extra-pyramidal features, cerebellar deficits, and distal muscle atrophy. MJD is thought to be caused by mutation of a single gene which has recently been mapped, using genetic linkage analysis, to a 29 cM region on chromosome 14q24.3-q32 in five Japanese families. A second disorder, spinocerebellar ataxia type 3 (SCA3), which has clinical symptoms similar to MJD, has also been linked to the same region of chromosome 14q in two French families. In order to narrow down the region of chromosome 14 which contains the MJD locus and to determine if this region overlaps with the predisposing locus for SCA3, we have performed genetic linkage analysis in seven MJD families, six of Portuguese/Azorean origin and one of Brazilian origin, using nine microsatellite markers mapped to 14q24.3-q32. Our results localise the MJD locus in these families to an 11 cM interval flanked by the markers D14S68 and AFM343vf1. In addition we show that this 11 cM interval maps within the 15 cM interval containing the SCA3 locus, suggesting that these diseases are allelic.

Machado Joseph disease is not an allele of the spinocerebellar ataxia 2 locus

Machado Joseph disease (MJD) is a progressive, spinocerebellar ataxia (SCA) with an autosomal dominant mode of inheritance and almost complete penetrance. Clinically, it is difficult to distinguish it from other autosomal dominantly inherited ataxias, and it has been suggested that MJD may be caused by an allelic variant of SCA. Exclusion of MJD from the SCA1 locus on chromosome 6p has previously been demonstrated. However, following the recent assignment of a second locus for spinocerebellar ataxia (SCA2) to chromosome 12q in a large Cuban kindred of Spanish origin, we have investigated linkage in MJD families using the two markers, D12S58 and PLA2, that flank this disease gene. The MJD locus was definitively excluded from an interval spanning approximately 70 cM, which includes these loci. These studies demonstrate that MJD and SCA2 are genetically distinct despite similarities in disease phenotype and ancestral origins of the patients. Thus, the as yet unmapped MJD locus represents a third SCA locus, providing further evidence for genetic heterogeneity within these disorders.

Machado-Joseph disease of Azorean ancestry in Brazil: the Catarina kindred. Neurological, neuroimaging, psychiatric and neuropsychological findings in the largest known family, the "Catarina" kindred

At the moment 9 seemingly independent families with the clinical diagnosis of MJD are known in Brazil. The largest family tree of Azorean ancestry contains 622 individuals in 9 generations. 236 were examined, 39 found to be affected by two examiners. Phenotypes I, II and III were expressed by 12, 23 and 4 patients with age of onset by phenotypes being 10-48, 14-54 and 30-55 respectively. Although clinically more severe, juvenile onset type I disease did not show as severe a ponto-mesencephalic atrophy on MRI as the father with type II disease of similar symptomatic duration. None of the 8 patients examined with MRI showed olivary atrophy or pallidal abnormalities. 12 affected and 23 at risk were evaluated with neuropsychological tests. Attention was normal in both groups. Verbal memory scores were below normal in the affected and there was greater decay with time than in the risk group. Both scored below normal in identifying silluettes and constructional praxis. Visual memory scores were well below normal for both, with many rotations but no omissions or confabulations. A peculiar pattern of multiplying internal details called "the fly-eye effect" was observed in 6 affected and 8 at risk. Defective color distinction when multiple colors presented close to each other, in face of proper naming of individual colors ("color simulatanagnosia"), was looked for in 29 people. 4/10 affected and 4/19 at risk showed this phenomenon. Cognitive dysfunctions in this MJD family are prominent in the sphere of vision. Whether they constitute an early manifestation in those at risk and thus serve as a clinical identifier of the illness is yet to be established. Depression was looked for in the history of the family with DSM III-R criteria and an attempt at quantification with the Montgomery-Asberg Rating Scale. There was no significant quantitative difference between affected and at risk. Once undeniably symptomatic however, the patients had no, or less depression than themselves before or at the early stages of the illness. Covert depression was appropriately excluded. Fully established MJD in this family seemed to exert a protective effect from depression.

The Machado-Joseph disease locus is different from the spinocerebellar ataxia locus (SCA1)

Machado-Joseph disease (MJD) is an autosomal dominant neurodegenerative spinocerebellar ataxia that has been described primarily in families of Azorean or Portuguese descent. MJD and chromosome 6p-linked spinocerebellar ataxia (SCA1) are difficult to differentiate clinically, and it has been suggested that they may be allelic variants of the same disorder. We have tested MJD families for linkage to six DNA sequence polymorphisms located on chromosome 6p, including the highly informative dinucleotide repeat, D6S89. Seventeen centimorgans telomeric to and 41 cM centromeric to D6S89, a region that includes the SCA1 locus reported to be within 3 cM of D6S89, have been excluded. These data provide conclusive evidence that MJD and SCA1 are nonallelic.

Prevalence of multiple sclerosis in the city of São Paulo, Brazil, in 1990

A case register of multiple sclerosis (MS) was set up in the city of São Paulo, Brazil, situated at a latitude of 23-24 degrees south. Cases were notified by neurologists, neuroradiologists and by an association of patients with MS. Prevalence rate was 4.27 x 10(-5) (men: 2.89 x 10(-5); women: 5.59 x 10(-5)), with a preponderance of young adults. We discuss here whether these rates are artifact due to poor health care facilities, to poor notification and deficiencies in diagnosis, or whether these rates are really low.

Selective electroencephalograph-guided microsurgical callosotomy for refractory generalized epilepsy

Between 1978 and 1985, 35 patients with medically refractory multiform seizures were submitted for sections of variable portions of the corpus callosum. Guided by intraoperative electroencephalographic and electrocorticographic monitoring, the section was carried out only in the portion of callosum that was involved in the maintenance of the bilaterally synchronous slow spike and wave discharge (as documented by intraoperative electrocorticography). In our patients, only part of the frontal corpus callosum needed to be sectioned to interrupt the bilateral synchrony of epileptic discharge. Of the 35 patients, operated on, 28 have had an adequate long-term follow up and are presented herein. All had significant improvement in seizure frequency and psychosocial functioning.

Anterior callosotomy as a substitute for hemispherectomy

Two patients with epilepsy and large hemispheric lesions underwent section of the frontal fibres of the corpus callosum for the treatment of seizures refractory to medical treatment. A severely retarded girl of 18 had encephalotrigeminal angiomatosis (Sturge-Weber syndrome) with multiple daily absences, tonic-clonic, myoclonic, atonic and adversive seizures since infancy. All types of fits--with the exception of adversive seizures and rare tonic-clonic fits--disappeared after anterior callosotomy. Another moderately retarded girl of 18 had an old cystic lesion over the entire territory of the left middle cerebral artery. She had had right hemiplegia since infancy and frequent brief absences and massive myoclonus triggered by unexpected sensory stimuli since the age of six years. Following anterior callosotomy there was an almost complete disappearance of the absences and a marked reduction of her startle myoclonus. Frontal callosotomy is a useful procedure in epileptics with large hemispheric lesions and carries less risk than hemispherectomy or total commissurotomy.

Anterior callosotomy in epileptics with multiform seizures and bilateral synchronous spike and wave EEG pattern

Cerebral commissurotomy is a well established procedure in the treatment of epileptics refractory to drug therapy. Breeching of the ventricles in complete commissurotomy carries a certain morbidity. This has led others to perform operations in which the entire corpus callosum or only its anterior portion with or without the anterior commissure were sectioned. Sectioning of the anterior corpus callosum alone is justified by: a) frequent appearance in patients of seizures attributable to a frontal focus, b) clinical and experimental evidence that frontal discharges spread across the corpus callosum leading to subsequent generalized its, c) the attempt to understand the mechanisms involved in generalized seizures, d) even further reduced surgical morbidity and neuropsychological disability. Five epileptics were submitted to anterior callosotomy. The seizures in all of them suggested a frontal focus and consisted of absences, adversive, tonic, atonic, and tonic-clonic attacks. All patients were incapacitated by the frequency of seizures. Their EEGs showed paroxysms of bilateral synchronous slow spike and wave with uni-, or multiple (including bilateral symmetrical) focal accentuation. In two patients there were additional independent temporal lobe discharges. Neuropsychological evaluation showed cognitive deficits caused by inattention paroxysms and absences. After anterior callosotomy there was marked reduction in frequency of all types of seizures, the greatest improvement being in the reduction of frequency of absences. There was a marked decrease in physical, social and neuropsychological disabilities.

Case report: computed tomography in the diagnosis of primary lymphoma of the central nervous system

A case of primary central nervous system lymphoma is presented with characteristics shown by computed tomography (CT) closely resembling those of the only other case reported in the literature. The combination of the arteriographic and CT appearances suggests the diagnosis of this radiosensitive group of tumors.

Whipple's disease confined to the brain: a case studied clinically and pathologically

A 40 year old man developed seizures, intermittent fever, and progressive dementia ending in coma and death after four years. The cerebrospinal fluid showed variable pleocytosis and occasional elevation of protein. The necropsy revealed many lesions characteristic of Whipple's disease confined to the grey matter of the brain. The pathological changes were studied with the light and electron microscope. The findings permitted an understanding of the temporal sequence of changes in the lesions. Involvement of the brain in this condition is rare, but the disease is treatable and the diagnosis can be made by brain biopsy.

Azorean disease of the nervous system

We studied a family of Portuguese ancestry from the Azores who suffered a progressive neurologic disease characterized by gait ataxia, features similar to Parkinson's disease in some patients, limitation of eye movements, widespread fasciculations of muscles, loss of reflexes in the lower limbs, followed by nystagmus, mild cerebellar tremor and extensor plantar responses. Two post-mortem examinations revealed loss of neurons and gliosis in the substantia nigra, nuclei pontis (and in the putamen in one case) as well as in the nuclei of the vestibular and other cranial nerves, columns of Clarke and anterior horns, in the spinal cord there were also loss of fibers in the fasciculi gracilis and mild changes in the pyramidal tracts. Comparison of the disease in this family with the findings reported in three families of similar ancestry, previously thought to have different disorders, suggests that they may all represent a single genetic entity with variable expression.