Evidence for topographic organization in the cerebellum of motor control versus cognitive and affective processing

Patients with cerebellar damage often present with the cerebellar motor syndrome of dysmetria, dysarthria and ataxia, yet cerebellar lesions can also result in the cerebellar cognitive affective syndrome (CCAS), including executive, visual spatial, and linguistic impairments, and affective dysregulation. We have hypothesized that there is topographic organization in the human cerebellum such that the anterior lobe and lobule VIII contain the representation of the sensorimotor cerebellum; lobules VI and VII of the posterior lobe comprise the cognitive cerebellum; and the posterior vermis is the anatomical substrate of the limbic cerebellum. Here we analyze anatomical, functional neuroimaging, and clinical data to test this hypothesis. We find converging lines of evidence supporting regional organization of motor, cognitive, and limbic behaviors in the cerebellum. The cerebellar motor syndrome results when lesions involve the anterior lobe and parts of lobule VI, interrupting cerebellar communication with cerebral and spinal motor systems. Cognitive impairments occur when posterior lobe lesions affect lobules VI and VII (including Crus I, Crus II, and lobule VIIB), disrupting cerebellar modulation of cognitive loops with cerebral association cortices. Neuropsychiatric disorders manifest when vermis lesions deprive cerebro-cerebellar-limbic loops of cerebellar input. We consider this functional topography to be a consequence of the differential arrangement of connections of the cerebellum with the spinal cord, brainstem, and cerebral hemispheres, reflecting cerebellar incorporation into the distributed neural circuits subserving movement, cognition, and emotion. These observations provide testable hypotheses for future investigations.     

Mental retardation and epilepsy in patients with isolated cerebellar hypoplasia

Congenital nonprogressive cerebellar ataxia includes a complex group of disorders with heterogeneous phenotypic and etiopathogenetic characteristics. Despite recent advances in the understanding of the role of the cerebellum in cognition and behavior, the opinion that the clinical presentation of congenital cerebellar diseases is principally linked to motor dysfunction is common. This is largely due to the lack of well-organized epidemiologic studies on the prevalence of nonmotor disturbances in cerebellar disease. The association between congenital cerebellar disease and epilepsy has rarely been described. We report clinical, neurophysiologic, neuroimaging, and neuropsychologic features in a group of 14 patients with congenital nonprogressive cerebellar ataxia associated with cerebellar hypoplasia, 5 of whom have familial disease, aiming to further a better knowledge of the prevalence of cognitive and/or emotional impairment and epilepsy. The results confirm that cerebellar hypoplasia predisposes individuals to psychomotor delay (71.4%) and cognitive impairment (85.7%). Moreover, the tendency toward abnormal electroencephalographic (EEG) findings (78.5%), associated in a minor percentage of cases with epilepsy (28.5%), is also evident in our study.     

The relationship between alcoholic cerebellar degeneration and cognitive and emotional functioning

Although it is now widely acknowledged that the cerebellum contributes to the modulation of higher-order cognitive and emotional functions, this relationship has not been extensively explored in perhaps the largest group of individuals with cerebellar damage, chronic alcoholics. Localised damage to the cerebellum has been associated with a specific constellation of deficits and has been termed the 'cerebellar cognitive affective syndrome' (CCAS) [Schmahmann, J.D., Sherman, J.C., 1998. The cerebellar cognitive affective syndrome. Brain 121, 561-579]. The CCAS describes a profile of impairments, including deficits in executive functioning and visuospatial skills, language disruption and altered personality and affective behaviour. It is conceivable that the CCAS may also develop in a subgroup of alcoholics with alcoholic cerebellar degeneration and may in part account for a proportion of the cognitive and affective deficits commonly observed with the condition. While evidence has emerged supporting such a relationship, methodological limitations and the lack of theoretically driven investigation of the contribution of cerebellar dysfunction to cognitive and emotional functioning in chronic alcoholics, preclude definitive conclusions being drawn.     

Cerebellar neurocognition: insights into the bottom of the brain

The traditional view on the core functions of the cerebellum consists of the regulation of motor coordination, balance and motor speech. However, during the past decades results from neuroanatomical, neuroimaging and clinical studies have substantially extended the functional role of the cerebellum to cognitive and affective regulation. Neuroanatomical studies convincingly showed cerebellar connectivity with associative areas of the cerebral cortex involved in higher cognitive functioning, while functional neuroimaging provided evidence of cerebellar activation during a variety of cognitive tasks. In addition, more systematic neuropsychological research performed in patients with cerebellar lesions and the development of more sensitive neuropsychological tests allowed clinicians to identify significant cognitive and affective disturbances following cerebellar damage. In this review, an overview is presented of the cerebellar role in a variety of cognitive processes, such as executive functioning, memory, learning, attention, visuo-spatial regulation, language and behavioral-affective modulation. In addition, recent evidence with regard to cerebellar induced clinical entities such as the cerebellar cognitive affective syndrome (CCAS) and the posterior fossa syndrome (PFS), will be discussed. Although extensive research has substantially broadened the insights in the cognitive and affective role of the cerebellum, the precise nature of the cerebellar contribution to cognitive and affective regulation is not yet clear. In this review experimental and clinical data will be discussed that substantiate the presumed neurobiological mechanisms underlying the cognitive and affective modulatory role of the cerebellum.     

Consensus Paper: Revisiting the Symptoms and Signs of Cerebellar Syndrome

The cerebellum is involved in sensorimotor operations, cognitive tasks and affective processes. Here, we revisit the concept of the cerebellar syndrome in the light of recent advances in our understanding of cerebellar operations. The key symptoms and signs of cerebellar dysfunction, often grouped under the generic term of ataxia, are discussed. Vertigo, dizziness, and imbalance are associated with lesions of the vestibulo-cerebellar, vestibulo-spinal, or cerebellar ocular motor systems. The cerebellum plays a major role in the online to long-term control of eye movements (control of calibration, reduction of eye instability, maintenance of ocular alignment). Ocular instability, nystagmus, saccadic intrusions, impaired smooth pursuit, impaired vestibulo-ocular reflex (VOR), and ocular misalignment are at the core of oculomotor cerebellar deficits. As a motor speech disorder, ataxic dysarthria is highly suggestive of cerebellar pathology. Regarding motor control of limbs, hypotonia, a- or dysdiadochokinesia, dysmetria, grasping deficits and various tremor phenomenologies are observed in cerebellar disorders to varying degrees. There is clear evidence that the cerebellum participates in force perception and proprioceptive sense during active movements. Gait is staggering with a wide base, and tandem gait is very often impaired in cerebellar disorders. In terms of cognitive and affective operations, impairments are found in executive functions, visual-spatial processing, linguistic function, and affective regulation (Schmahmann’s syndrome). Nonmotor linguistic deficits including disruption of articulatory and graphomotor planning, language dynamics, verbal fluency, phonological, and semantic word retrieval, expressive and receptive syntax, and various aspects of reading and writing may be impaired after cerebellar damage. The cerebellum is organized into (a) a primary sensorimotor region in the anterior lobe and adjacent part of lobule VI, (b) a second sensorimotor region in lobule VIII, and (c) cognitive and limbic regions located in the posterior lobe (lobule VI, lobule VIIA which includes crus I and crus II, and lobule VIIB). The limbic cerebellum is mainly represented in the posterior vermis. The cortico-ponto-cerebellar and cerebello-thalamo-cortical loops establish close functional connections between the cerebellum and the supratentorial motor, paralimbic and association cortices, and cerebellar symptoms are associated with a disruption of these loops.     

Suppression of motor cortical excitability by electrical stimulation over the cerebellum in ataxia

We studied the effect of electrical stimulation over the cerebellum on electromyographic responses evoked by magnetic stimulation over the cerebral motor cortex in 14 normal volunteers and 32 patients with ataxia due to various disorders. In all the normal subjects, stimulation over the cerebellum significantly reduced the size of electromyographic response in the first dorsal interosseous muscle evoked by magnetic cortical stimulation, when the cerebellar stimulus preceded the cortical stimulus by 5, 6, and 7 msec. This suppression was absent or reduced in ataxic patients who had atrophy of the cerebellar hemispheres as demonstrated by magnetic resonance imaging and in patients with dysfunction of the cerebellothalamocortical pathway who had lesions in the superior cerebellar peduncle or in the motor thalamus. In contrast, suppression was normal in ataxic patients who had pontine lesions that affected the pontocerebellar afferent pathway to the cerebellum. Results were also normal in patients without cerebellar ataxia, such as those with Parkinson's disease, sensory ataxia, and cerebrovascular disease without ataxia. We conclude that electrical stimulation activates cerebellar structures that suppress motor cortical excitability through a cerebellothalamocortical pathway and that the afferent systems to the cerebellum make no or little contribution to the effect. The technique described here would be useful for distinguishing ataxia due to lesions of cerebellar afferent pathway from other types of cerebellar ataxia.     

Topography of Cerebellar Deficits in Humans

The cerebellum is a key-piece for information processing and is involved in numerous motor and nonmotor activities, thanks to the anatomical characteristics of the circuitry, the enormous computational capabilities and the high connectivity to other brain areas. Despite its uniform cytoarchitecture, cerebellar circuitry is segregated into functional zones. This functional parcellation is driven by the connectivity and the anatomo-functional heterogeneity of the numerous extra-cerebellar structures linked to the cerebellum, principally brain cortices, precerebellar nuclei and spinal cord. Major insights into cerebellar functions have been gained with a detailed analysis of the cerebellar outputs, with the evidence that fundamental aspects of cerebrocerebellar operations are the closed-loop circuit and the predictions of future states. Cerebellar diseases result in disturbances of accuracy of movements and lack of coordination. The cerebellar syndrome includes combinations of oculomotor disturbances, dysarthria and other speech deficits, ataxia of limbs, ataxia of stance and gait, as well as often more subtle cognitive/behavioral impairments. Our understanding of the corresponding anatomo-functional maps for the human cerebellum is continuously improving. We summarize the topography of the clinical deficits observed in cerebellar patients and the growing evidence of a regional subdivision into motor, sensory, sensorimotor, cognitive and affective domains. The recently described topographic dichotomy motor versus nonmotor cerebellum based upon anatomical, functional and neuropsychological studies is also discussed.     

Cognitive and Emotional Deficits in Chronic Alcoholics: a Role for the Cerebellum?

It is now widely accepted that in addition to motor coordination, the cerebellum is also involved in the modulation of cognitive and affective processes. Despite alcoholic cerebellar degeneration (ACD) being the most common form of cerebellar disorder, little systematic investigation of cerebellar-mediated cognitive and affective deficits has occurred in chronic alcoholics. Forty-nine chronic alcoholics and 29 healthy control participants underwent testing of cognitive and affective function, along with measurement of cerebellar ataxia using the International Cooperative Ataxia Rating Scale (Trouillas et al., Journal of the Neurological Sciences 145:205–11, 1997). The alcoholic group demonstrated significantly poorer performance as compared to the control group in a number of domains, including visuospatial and language skills, psychomotor speed, new learning and memory, executive functioning, and emotional regulation and affect processing. There were no differences between the alcoholic and control groups in immediate attention and working memory abilities. Years of heavy drinking and total period of abstinence were found to be the best predictors of cognitive and emotional function in the alcoholic group. After accounting for alcohol chronicity, there was still a relationship between the degree of clinical signs of ACD and some areas of cognitive and emotional functioning, including language, executive functioning, processing speed and affect processing. The results suggest that some of the cognitive and affective deficits observed in chronic alcoholics may be mediated, at least in part, by cerebellar dysfunction. These findings add support to the theory of disruption to bidirectional cerebro-cerebellar circuitry underlying cognitive and affective deficits in chronic alcoholics.     

Development of a Psychiatric Disorder Linked to Cerebellar Lesions

Cerebellar dysfunction plays a critical role in neurodevelopmental disorders with long-term behavioral and neuropsychiatric symptoms. A 43-year-old woman with a cerebellum arteriovenous malformation and history of behavioral dysregulation since childhood is described. After the rupture of the cerebellar malformation in adulthood, her behavior morphed into specific psychiatric symptoms and cognitive deficits occurred. The neuropsychological assessment evidenced impaired performance in attention, visuospatial, memory, and language domains. Moreover, psychiatric assessment indicated a borderline personality disorder. Brain MRI examination detected macroscopic abnormalities in the cerebellar posterior lobules VI, VIIa (Crus I), and IX, and in the posterior area of the vermis, regions usually involved in cognitive and emotional processing. The described patient suffered from cognitive and behavioral symptoms that are part of the cerebellar cognitive affective syndrome. This case supports the hypothesis of a cerebellar role in personality disorders emphasizing the importance of also examining the cerebellum in the presence of behavioral disturbances in children and adults.     

小脑卒中患者认知域受损特点及影像学研究进展

小脑情感认知综合征(cerebellar cognitive affective syndrome,CCAS)指小脑病变患者所出现的认知障碍,其特征表现为执行、视空间、语言障碍及人格的改变.单纯性小脑卒中患者可出现CCAS,且基于体素的结构影像研究验证了认知障碍的发生及受损特点与病灶部位密切相关.此外,功能影像研究提示...     

Developmental Coordination Disorder: Disruption of the Cerebello-Cerebral Network evidenced by SPECT

Little is known about the neurobiological substrate of developmental coordination disorder (DCD), a neuro-developmental syndrome with significant, negative impact on the motor, cognitive and affective level throughout lifespan. This paper reports the clinical, neurocognitive and neuroradiological findings of a 19-year-old patient with typical DCD. As demonstrated by mild ataxia and a close semiological correspondence with the recently acknowledged ‘cerebellar cognitive affective syndrome’, clinical and neurocognitive investigations unambiguously indicated functional disruption of the cerebellum. Structural MRI of the brain confirmed cerebellar involvement revealing a slight anterior/superior asymmetry of vermal fissures consistent with rostral vermisdysplasia. Although this abnormality of vermal fissuration is generally considered an incidental neuroradiological finding without any clinical relevance, a potentially subtle impact on the developmental level has never been formally excluded. In addition to a generally decreased perfusion of the cerebellum, a quantified Tc-99m-ECD SPECT disclosed functional suppression of the anatomoclinically suspected supratentorial regions involved in the execution of planned actions, visuo-spatial processing and affective regulation. Based on these findings, it is hypothesised that the cerebellum is crucially implicated in the pathophysiologcial mechanisms of DCD, reflecting disruption of the cerebello-cerebral network involved in the execution of planned actions, visuo-spatial cognition and affective regulation.     

Contribution of the cerebellum to cognition

The role of the cerebellum in motor control and motor learning is well-recognised. Patients with cerebellar disease consult a doctor because of their motor dysfunction (ataxia). For nearly three decades intense research has been addressing the question to what extent the cerebellum may support cognitive functions. Neuroanatomic findings support the notion that posterolateral parts of the cerebellum contribute to cognition. Although there is a huge number of neuropsychological studies in patients with cerebellar disease, interpretation of findings is frequently hampered by the accompanying motor disorders and extracerebellar lesions. This review summarises the anatomic findings and attempts to give a critical evaluation of findings in human lesion studies. There are good reasons to believe that cerebellar disorders, both cerebellar degeneration and focal cerebellar lesions, may lead to certain cognitive dysfunctions. Disorders in executive function, in particular working memory, and certain higher language tasks are best documented. However, disorders in adults with chronic diseases tend to be mild. Dysfunction appears to be more prominent in patients with acute disease.     

Viewing the Personality Traits Through a Cerebellar Lens: a Focus on the Constructs of Novelty Seeking,Harm Avoidance,and Alexithymia

The variance in the range of personality trait expression appears to be linked to structural variance in specific brain regions. In evidencing associations between personality factors and neurobiological measures, it seems evident that the cerebellum has not been up to now thought as having a key role in personality. This paper will review the most recent structural and functional neuroimaging literature that engages the cerebellum in personality traits, as novelty seeking and harm avoidance, and it will discuss the findings in the context of contemporary theories of affective and cognitive cerebellar function. By using region of interest (ROI)- and voxel-based approaches, we recently evidenced that the cerebellar volumes correlate positively with novelty seeking scores and negatively with harm avoidance scores. Subjects who search for new situations as a novelty seeker does (and a harm avoiding does not do) show a different engagement of their cerebellar circuitries in order to rapidly adapt to changing environments. The emerging model of cerebellar functionality may explain how the cerebellar abilities in planning, controlling, and putting into action the behavior are associated to normal or abnormal personality constructs. In this framework, it is worth reporting that increased cerebellar volumes are even associated with high scores in alexithymia, construct of personality characterized by impairment in cognitive, emotional, and affective processing. On such a basis, it seems necessary to go over the traditional cortico-centric view of personality constructs and to address the function of the cerebellar system in sustaining aspects of motivational network that characterizes the different temperamental traits.     

Cerebellar Cognitive Affective Syndrome in Machado Joseph Disease: Core Clinical Features

The cerebellum is no longer considered a purely motor control device, and convincing evidence has demonstrated its relationship to cognitive and emotional neural circuits. The aims of the present study were to establish the core cognitive features in our patient population and to determine the presence of Cerebellar Cognitive Affective Syndrome (CCAS) in this group. We recruited 38 patients with spinocerebellar ataxia type 3 (SCA3) or Machado–Joseph disease (MJD)-SCA3/MJD and 31 controls. Data on disease status were recorded (disease duration, age, age at onset, ataxia severity, and CAG repeat length). The severity of cerebellar symptoms was measured using the International Cooperative Ataxia Rating Scale and the Scale for the Assessment and Rating of Ataxia. The neuropsychological assessment consisted of the Mini-Mental State Examination, Clock Drawing Test, Wechsler Adult Intelligence Scale, Rey–Osterrieth Complex Figure, Wisconsin Card Sorting Test, Stroop Color–Word Test, Trail-Making Test, Verbal Paired Associates, and verbal fluency tests. All subjects were also submitted to the Hamilton Anxiety Scale and Beck Depression Inventory. After controlling for multiple comparisons, spatial span, picture completion, symbol search, Stroop Color–Word Test, phonemic verbal fluency, and Trail-Making Tests A and B were significantly more impaired in patients with SCA3/MJD than in controls. Executive and visuospatial functions are impaired in patients with SCA3/MJD, consistent with the symptoms reported in the CCAS. We speculate on a possible role in visual cortical processing degeneration and executive dysfunction in our patients as a model to explain their main cognitive deficit.     

Ataxic Hemiparesis: Neurophysiological Analysis by Cerebellar Transcranial Magnetic Stimulation

The aim of this study was to investigate physiological mechanisms underlying ataxia in patients with ataxic hemiparesis. Subjects were three patients with ataxic hemiparesis, whose responsible lesion was located at the posterior limb of internal capsule (case 1), thalamus (case 2), or pre- and post-central gyri (case 3). Paired-pulse transcranial magnetic stimulation (TMS) technique was used to evaluate connectivity between the cerebellum and contralateral motor cortex. The conditioning cerebellar stimulus was given over the cerebellum and the test stimulus over the primary motor cortex. We studied how the conditioning stimulus modulated motor evoked potentials (MEPs) to the cortical test stimulus. In non-ataxic limbs, the cerebellar stimulus normally suppressed cortical MEPs. In ataxic limbs, the cerebellar inhibition was not elicited in patients with a lesion at the posterior limb of internal capsule (case 1) or thalamus (case 2). In contrast, normal cerebellar inhibition was elicited in the ataxic limb in a patient with a lesion at sensori-motor cortex (case 3). Lesions at the internal capsule and thalamus involved the cerebello-thalamo-cortical pathways and reduced the cerebellar suppression effect. On the other hand, a lesion at the pre- and post-central gyri should affect cortico-pontine pathway but not involve the cerebello-thalamo-cortical pathways. This lack of cerebello-talamo-cortical pathway involvement may explain normal suppression in this patient. The cerebellar TMS method can differentiate cerebellar efferent ataxic hemiparesis from cerebellar afferent ataxic hemiparesis.     

Clinical manifestation of focal cerebellar disease as related to the organization of neural pathways

Neural pathways connect different parts of the cerebellum to different parts of the central nervous system. The cerebellum may be divided anatomically and functionally into three major regions. The cerebellar hemispheres and a small part of the posterior lobe vermis form the pontocerebellum, which receives inputs from the cerebral cortex via the pontine nuclei. The anterior lobe and most of the posterior lobe vermis make up the spinocerebellum, which receives afferents from the spinal cord. The nodulus and flocculus are connected with the vestibular nuclei and constitute the vestibulocerebellum. Most cases of cerebellar disease affect more than one region and different pathways. Hence, they cause generalized cerebellar symptoms dominated by impaired motor control and balance. Focal syndromes after restricted cerebellar lesions are rare. Isolated spinocerebellar affection may give gait ataxia. Vestibulocerebellar disease causes equilibrium disturbances with truncal ataxia and nystagmus. Pontocerebellar lesions typically give ipsilateral limb ataxia, but also dysartria and oculomotor dysfunction if vermal parts are involved. The clinical picture is in most cases of cerebellar disease dominated by motor disturbances, but the cerebellum also participates in the modulation of autonomic and affective responses and in cognitive functions. The cerebrocerebellar and hypothalamocerebellar circuits may be important for these tasks.     

From movement to thought: Anatomic substrates of the cerebellar contribution to cognitive processing

The cerebellar contribution to cognitive operations and emotional behavior is critically dependent upon the existence of plausible anatomic substrates. This paper explores these anatomic substrates, namely, the incorporation of the associative and paralimbic cerebral areas into the cerebrocerebellar circuitry in nonhuman primates. Using the novel information that has emerged concerning this system, proposed rules are derived and specific hypotheses offered concerning cerebellar function and the relationship between cerebellum and nonmotor behavior, as follow. (1) The associative and paralimbic incorporation into the cerebrocerebellar circuit is the anatomic underpinning of the cerebellar contribution to cognition and emotion. (2) There is topographic organization of cognitive and behavioral functions within the cerebellum. The archicerebellum, vermis, and fastigial nucleus are principally concerned with affective and autonomic regulation and emotionally relevant memory. The cerebellar hemispheres and dentate nucleus are concerned with executive, visual-spatial, language, and other mnemonic functions. (3) The convergence of inputs from multiple associative cerebral regions to common areas within the cerebellum facilitates cerebellar regulation of supramodal functions. (4) The cerebellar contribution to cognition is one of modulation rather than generation. Dysmetria of (or ataxic) thought and emotion are the clinical manifestations of a cerebellar lesion in the cognitive domain. (5) The cerebellum performs the same computations for associative and paralimbic functions as it does for the sensorimotor system. These proposed rules and the general and specific hypotheses offered in this paper are testable using functional neuroimaging techniques. Neuroanatomy and functional neuroimaging may thus be mutually advantageous in predicting and explaining new concepts of cerebellar function. © 1996 Wiley-Liss, Inc.     

Cerebellar ataxic gait

In this review, we have mainly discussed the cerebellar ataxic gait. The cerebellum can be divided into 3 phylogenically different lobes: the archicerebellum, paleocerebellum, and neocerebellum. The main components of the cerebellar circuit are 2 types of neurons, i.e., the Purkinje cells and granule cells and 3 types of fibers, i.e., mossy fibers, climbing fibers (cerebellar afferent fibers), and parallel fibers (axons of granule cells) Theoretically, cerebellar ataxia is considered to be caused by any lesions that develop within this circuit. Before diagnosing any symptoms as ataxia, we should first exclude weakness, sensory disturbances or vestibular dysfunction to explain those symptoms. Cerebellar ataxia usually causes several neurological deficits such as antagonist hypotonia, asynergy, dysmetria, dyschronometria, and dysdiadochokinesia. Ataxic gait is one of the cardinal features of the cerebellar symptoms. The clinical features of cerebellar ataxic gait usually include a widened base, unsteadiness and irregularity of steps, and lateral veering. Locomotion in individuals with cerebellar ataxia is characterized by a significantly reduced step frequency with a prolonged stance and double limb support duration. All gait measurements are highly variable in cerebellar ataxia. The characteristic clinical features of several cerebellar diseases have been summarized in this review. Even though the rehabilitation for cerebellar ataxia is not fully supported by much enough clinical evidence, repeated motor training, bandages or light weights has sometimes beneficial effects on ataxic limbs.     

Cognitive and social cognitive functioning in spinocerebellar ataxia

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.