Executive and emotional dysfunction in Machado-Joseph disease

Cognitive and social cognitive functioning in spinocerebellar ataxia : a preliminary characterization

INTRODUCTION

The spinocerebellar ataxias (SCAs), are rare neurodegenerative disorders caused by distinct genetic mutations. Clinically, the SCAs are characterised by progressive ataxia and a variety of other features, including cognitive dysfunction. The latter is consistent with a growing body of evidence supporting a cognitive as well as motor role for the cerebellum. Recent suggestions of cerebellar involvement in social cognition have not been extensively explored in these conditions. The availability of definitive molecular diagnosis allows genetically defined subgroups of SCA patients, with distinct patterns of cerebellar and extracerebellar involvement, to be tested comparatively using a common battery of tests of general, social and emotional cognition.

METHODS

: Nine patients with SCA6, and 6 with SCA3 were assessed using a comprehensive battery of neuropsychological instruments, encompassing domains of memory, language, visuo-spatial skills, calculation, attention and executive function, emotional processing and theory of mind (ToM).

RESULTS

There were no deficits in visuo-spatial processing or calculation in either group, while individuals with naming and attentional difficulties were seen in both. Deficits in memory and executive function were present in both conditions, albeit more pronounced in SCA3. By contrast, both groups demonstrated consistently poor performance on ToM tests, and normal attribution of social and emotional responses.

CONCLUSION

The data support the hypothesis that the cerebellum is important for cognitive as well as motor activity. The pattern of overlap of domain impairments provides tentative preliminary evidence that there is a cerebellar contribution to aspects of memory and executive function and ToM, and that other domains depend more on neural system outside the cerebellum. The findings relating to ToM are relevant to the possibility of cerebellar involvement in autism.

Cognition in hereditary ataxia

Apart from motor control the cerebellum has been implicated in higher cortical functions such as memory, fronto-executive functions, visuoconstructive skills and emotion. Clinical descriptions of hereditary ataxias mention cognitive impairment to a variable extent. Systematic neuropsychological studies are limited. Regarding the neuropathological pattern in different SCA types, cognitive deficits in hereditary ataxias are not likely to be contingent upon cerebellar degeneration but to result from disruption of cerebrocerebellar circuitries at various levels in the CNS.

Regional patterns of cerebral glucose metabolism in spinocerebellar ataxia type 2, 3 and 6 : a voxel-based FDG-positron emission tomography analysis

The purpose of this study was to investigate the regional patterns of cerebral metabolic deficits by voxel-based FDGPET analysis in patients with distinct spinocerebellar ataxia (SCA) genotypes, including SCA type 2 (SCA2), SCA3, and SCA6. Nine patients with SCA2, 12 with SCA3, seven with SCA6, and 23 healthy control subjects were recruited. The clinical severity of the patients' cerebellar ataxia was evaluated according to the International Cooperative Ataxia Rating Scale. The brain glucose metabolism was evaluated with 2- [fluorine 18]-fluoro-2-deoxy-D: -glucose (FDG) positron emission tomography. Group data were analyzed and compared by voxelbased analysis. In SCA2, FDG utilization was significantly reduced in the cerebellum, pons, parahippocampal gyrus and frontal cortex. In SCA3, FDG metabolism in the cerebellum, parahippocampal gyrus of the limbic system, and lentiform nucleus was decreased. In SCA6, FDG metabolism was diminished in the cerebellum and the frontal and prefrontal cortices. On group comparisons, while all SCAs have impaired cerebellar functions, the cerebellar FDG metabolism was most severely compromised in SCA2. Instead, the FDG metabolism in the lentiform nucleus and medulla was characteristically worst in SCA3. There was no brainstem involvement in SCA6.

Depressive Symptoms in Machado-Joseph Disease (SCA3) Patients and Their Relatives

OBJECTIVES

It was the aim of this study to determine the depression scores of Machado-Joseph disease (MJD) patients, their spouses, and individuals at 50% risk for MJD, and second, to verify the existence of a correlation between depressive symptoms and the degree of motor incapacitation.

SUBJECTS AND METHODS

Two hundred and forty-six individuals aged > or =18 years were studied: 79 MJD patients (group 1), 43 spouses of MJD patients (group 2), 80 individuals at risk for MJD (group 3), and a control group (group 4) composed of 44 patients with multiple sclerosis (MS). The following two tools were applied: the Beck Depression Inventory and the Barthel index of physical incapacitation, both in an adapted Brazilian Portuguese version.

RESULTS

Moderate to severe depressive scores were found in 33.5% of patients in the MJD families, in 16.3% of the spouses, and in 6.3% of the individuals at risk. This linear reduction between MJD family members was statistically significant (p < 0.0001, ANOVA). Depressive scores were also associated with age and the female sex. A direct correlation between Beck Depression Inventory scores and motor incapacitation was found in MJD patients (r = 0.507, Pearson correlation, p < 0.0001). Although the depressive symptoms in the control group with MS were higher than those found in MJD patients (59% of MS patients showed moderate to severe scores), depression did not correlate with physical incapacitation, age, or education attainment in the MS group.

CONCLUSIONS

Depressive symptoms are rather common in MJD patients and in their spouses (caregivers). In this condition, depression seemed to be more reactive than primarily related to the disease process itself.

Spinocerebellar ataxia type 3 (SCA3): thalamic neurodegeneration occurs independently from thalamic ataxin-3 immunopositive neuronal intranuclear inclusions

In the last years progress has been made regarding the involvement of the thalamus during the course of the currently known polyglutamine diseases. Although recent studies have shown that the thalamus consistently undergoes neurodegeneration in Huntington's disease (HD) and spinocerebellar ataxia type 2 (SCA2) it is still unclear whether it is also a consistent target of the pathological process of spinocerebellar ataxia type 3 (SCA3). Accordingly we studied the thalamic pathoanatomy and distribution pattern of ataxin-3 immunopositive neuronal intranuclear inclusions (NI) in nine clinically diagnosed and genetically confirmed SCA3 patients and carried out a detailed statistical analysis of our findings. During our pathoanatomical study we disclosed (i) a consistent degeneration of the ventral anterior, ventral lateral and reticular thalamic nuclei; (ii) a degeneration of the ventral posterior lateral nucleus and inferior and lateral subnuclei of the pulvinar in the majority of these SCA3 patients; and (iii) a degeneration of the ventral posterior medial and lateral posterior thalamic nuclei, the lateral geniculate body and some of the limbic thalamic nuclei in some of them. Upon immunocytochemical analysis we detected NI in all of the thalamic nuclei of all of our SCA3 patients. According to our statistical analysis (i) thalamic neurodegeneration and the occurrence of ataxin-3 immunopositive thalamic NI was not associated with the individual length of the CAG-repeats in the mutated SCA3 allele, the patients age at disease onset and the duration of SCA3 and (ii) thalamic neurodegeneration was not correlated with the occurrence of ataxin-3 immunopositive thalamic NI. This lack of correlation may suggest that ataxin-3 immunopositive NI are not immediately decisive for the fate of affected nerve cells but rather represent unspecific and pathognomonic morphological markers of SCA3.

Cerebellar volumes in pediatric maltreatment-related posttraumatic stress disorder

BACKGROUND

The results of previous studies suggest structural brain differences in pediatric maltreatment-related posttraumatic stress disorder (PTSD) However, posterior fossa volumes were not examined, despite the consensus that the cerebellum is important in emotional and cognitive development. We investigated the relationship between structural volumes of the cerebellum hemispheres, vermis, brainstem, and clinical variables in pediatric maltreatment-related PTSD.

METHODS

Fifty-eight psychotropic-naïve maltreated children and adolescents with DSM-IV PTSD were compared with two groups of pediatric subjects who had no DSM-IV criteria A trauma histories: 1) 13 with pediatric generalized anxiety disorder, and 2) 98 healthy non-abused children and adolescents. Subjects underwent a comprehensive psychiatric assessment and an anatomical magnetic resonance image brain scan.

RESULTS

Unadjusted means of the left, right, and total cerebellum were smaller in the PTSD group. The group differences remained significant in the left cerebellum, right cerebellum, and total cerebellum in the analyses adjusted for cerebral volume, sociodemographic, and IQ variables. Cerebellar volumes positively correlated with age of onset of the trauma that lead to PTSD and negatively correlated with the duration of the trauma that lead to PTSD. Cerebellar volumes were larger in boys versus girls, but there was no group x gender interaction. There were significant positive correlations between IQ measures and volumetric variables.

CONCLUSIONS

The results support cerebellar volume differences in maltreated children and adolescents with PTSD. Further studies are warranted.

Cognitive impairment in spinocerebellar ataxia type 8

OBJECTIVES

Only a limited number of studies have investigated the cognitive performances of spinocerebellar ataxia (SCA) patients. In none of the SCA8 studies have the neuropsychological test performances been the primary measures. The objective of the current study was to investigate the characteristics of cognitive deficits in SCA8.

METHODS

Ten SCA8 patients and ten case-by-case matched control subjects underwent a comprehensive neuropsychological examination evaluating attention and information processing, concept formation, reasoning and executive functions, verbal production, memory and learning and visuoperceptual and -constructive functions.

RESULTS

SCA8 patients demonstrated deficits primarily in attention and information processing, as well as in concept formation, reasoning, executive functions and verbal production. Visuoperceptual and -constructive functions, as well as most of the performances of memory were unaffected.

CONCLUSIONS

Cognitive impairments, especially those related to attention, information processing and executive functions, seem to be a clinical feature of SCA8 disease.