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.     

Posterior Fossa Syndrome in an Adult Patient Following Surgical Evacuation of an Intracerebellar Haematoma

The posterior fossa syndrome (PFS) consists of transient cerebellar mutism, cognitive symptoms and neurobehavioural abnormalities that typically develop in children following posterior fossa tumour resection. Although PFS has been documented in more than 350 paediatric cases, reports of adult patients with a vascular aetiology are extremely rare. In addition, the pathophysiological substrate of the syndrome remains unclear. We report an adult patient with PFS after surgical evacuation of a cerebellar bleeding. After 45 days of (akinetic) mutism, the patient’s cognitive and behavioural profile closely resembled the “cerebellar cognitive–affective syndrome”. A quantified SPECT study showed perfusional deficits in the anatomoclinically suspected supratentorial areas, subserving language dynamics, executive functioning, spatial cognition and affective regulation. We hypothesize that cerebello-cerebral diaschisis might be an important pathophysiological mechanism underlying akinetic mutism, cognitive deficits and behavioural–affective changes in adult patients with PFS.     

The Cerebellar Cognitive Affective/Schmahmann Syndrome: a Task Force Paper

Sporadically advocated over the last two centuries, a cerebellar role in cognition and affect has been rigorously established in the past few decades. In the clinical domain, such progress is epitomized by the “cerebellar cognitive affective syndrome” (“CCAS”) or “Schmahmann syndrome.” Introduced in the late 1990s, CCAS reflects a constellation of cerebellar-induced sequelae, comprising deficits in executive function, visuospatial cognition, emotion–affect, and language, over and above speech. The CCAS thus offers excellent grounds to investigate the functional topography of the cerebellum, and, ultimately, illustrate the precise mechanisms by which the cerebellum modulates cognition and affect. The primary objective of this task force paper is thus to stimulate further research in this area. After providing an up-to-date overview of the fundamental findings on cerebellar neurocognition, the paper substantiates the concept of CCAS with recent evidence from different scientific angles, promotes awareness of the CCAS as a clinical entity, and examines our current insight into the therapeutic options available. The paper finally identifies topics of divergence and outstanding questions for further research.

     

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.     

Neurobehavioral alterations in an adolescent following posterior fossa tumor resection

The posterior fossa syndrome (PFS) consists of a variety of symptoms, including cerebellar mutism, behavioral disturbances and personality changes. We report longitudinal clinical, neuroradiological and neurobehavioral findings in a 19-year-old left-handed patient, diagnosed with attentional deficit hyperactivity disorder (ADHD) at the age of 12, who underwent posterior fossa tumor resection. Although the patient did not develop cerebellar mutism after surgery, marked apathy and emotional indifference, urinary retention, eye-lid apraxia and visual hallucinosis became apparent after a brief interval of normal functioning. Based on these findings it is argued that the PFS might be considered a semiological heterogeneous condition with variable clinical expressions. Long-term follow-up investigations revealed subtle, but significant cognitive and affective deficits, resembling the cerebellar cognitive affective syndrome in adults. As demonstrated by functional neuroimaging studies with SPECT, symptoms were associated with perfusional deficits in the anatomoclinically suspected supratentorial regions, reflecting the distant impact of the cerebellum on cognitive and affective functions.     

Cerebellar agenesis II: Motor and language functions

In a former study of a patient with cerebellar agenesis (HK) mild motor deficits, problems in delay eyeblink conditioning and mild to moderate deficits in IQ, planning behavior, visuospatial abilities, visual memory, and attention were found. The present study reports additional findings in the same patient. In the motor domain, impairments in fine motor manipulations, trace eyeblink conditioning and motor imagination in a functional magnetic resonance (fMRI) study were found. Based on fMRI findings; however, cortical areas involved in a tapping task did not significantly differ from a healthy control group. In the cognitive domain, deficits in speech comprehension as well as verbal learning and declarative memory were present. No significant affective symptoms were observed. Although problems in executive, visuospatial and language tasks are in agreement with the so-called cerebellar cognitive affective syndrome—other possibilities remain. Non-motor impairments in HK might also be a consequence of lacking motor abilities in development and motor deficits may interfere with the performance of parts of the cognitive tasks. In addition, lack of promotion and learning opportunities in childhood may contribute and mental retardation based on extracerebellar dysfunction cannot be excluded.     

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.     

Cerebellar cognitive affective syndrome without global mental retardation in two relatives with Gillespie syndrome

Although previous studies of Gillespie syndrome have systematically reported a generalized delay of cognitive development (mental retardation or oligophrenia), psychometric data to substantiate this view are strikingly absent. In the present study two first degree relatives (mother and daughter) with Gillespie syndrome were neuropsychologically investigated. Aside from a marked asymmetry in the Wechsler-IQ profile, consisting of significantly better results on the verbal [Verbal IQ (VIQ)] than on the nonverbal part [Performance IQ (PIQ)] of the test, cognitive and behavioral assessments revealed a pattern of abnormalities that closely resembles the "cerebellar cognitive and affective syndrome" (CeCAS) (Schmahmann and Sherman, 1998). Aside from prefrontal dysexecutive dysfunctions such as disturbed cognitive planning and set-shifting, parietal lobe involvement was reflected by impaired visuo-spatial memory and visuo-spatial disorganization in constructional tasks. Within the linguistic domain involvement of the prefrontal and temporal language regions was indicated by impaired letter fluency, incidences of agrammatism, apraxia of speech and disrupted language dynamics. With regard to mood and behavior, a number of personality and affective characteristics were found that are typically associated with prefrontal lobe damage and dysfunction of limbic related regions in the cingulate and parahippocampal gyri. Disinhibited symptoms characterized behavior and affect of the mother while the daughter displayed a variety of inhibited symptoms. As a result, behavioral and cognitive findings in these patients do not support the prevailing view of a global mental retardation as a cardinal feature of Gillespie syndrome but primarily reflect cerebellar induced neurobehavioral dysfunctions following disruption of the cerebrocerebellar anatomical circuitry.     

The Posterior Fossa and Foreign Accent Syndrome: Report of Two New Cases and Review of the Literature

Foreign accent syndrome is a rare motor speech disorder that causes patients to speak their language with a non-native accent. In the neurogenic condition, the disorder develops after lesions in the language dominant hemisphere, often affecting Broca’s area, the insula, the supplementary motor area and the primary motor cortex. Here, we present two new cases of FAS after posterior fossa lesions. The first case is a 44-year-old, right-handed, Dutch-speaking man who suffered motor speech disturbances and a left hemiplegia after a pontine infarction. Quantified SPECT showed a bilateral hypoperfusion in the inferior lateral prefrontal and medial inferior frontal regions as well as a significant left cerebellar hypoperfusion. Further clinical investigations led to an additional diagnosis of brainstem cognitive affective syndrome which closely relates to Schmahmann’s syndrome. The second patient was a 72-year-old right-handed polyglot English man who suffered a stroke in the vascular territory of the left posterior inferior cerebellar artery (PICA) and developed a foreign accent in his mother tongue (English) and in a later learnt language (Dutch). In this paper, we discuss how the occurrence of this peculiar motor speech disorder can be related to a lesion affecting the posterior fossa structures.     

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.     

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.     

Cognitive, linguistic and affective disturbances following a right superior cerebellar artery infarction: a case study

The cerebellar cognitive affective syndrome (CCAS) is a neurobehavioral syndrome that may develop after congenital and acquired cerebellar lesions. The syndrome consists of deficits in executive functioning, spatial cognition, visual-spatial memory and language and also involves personality and behavioral changes. We describe a 58-year-old right-handed man who in addition to affective disturbances presented with a unique combination of cognitive and linguistic deficits following an ischemic infarction in the vascular territory of the right superior cerebellar artery (SCA). Neurocognitive and neurolinguistic examinations were performed in the acute phase (10 days post-onset) and lesion phase (four weeks post-onset) of the stroke. A Tc-99m-ECD SPECT study was performed five weeks after the stroke. Acute phase data revealed a generalized cognitive decline and mild transcortical sensory aphasia. In the lesion phase, the neurobehavioral tableau was dominated by executive dysfunctions, disrupted divided attention, disturbed visual-spatial organization and behavioral abnormalities. Neurolinguistic investigations disclosed visual dyslexia and surface dysgraphia. Reading of words and visual lexical decision tasks of words and nonwords were severely defective and predominantly characterized by visual errors. In addition, writing irregular and ambiguous words resulted in regularization errors (phonologically plausible errors based on phoneme-grapheme correspondence rules). In the absence of any structural damage in the supratentorial brain regions, a quantified SPECT study showed a relative hypoperfusion in the right cerebellar hemisphere and the left medial frontal lobe. CCAS is for the first time reported in association with visual dyslexia and surface dysgraphia. We hypothesize that the cognitive and linguistic deficits might result from functional disruption of the cerebellar-encephalic pathways, connecting the cerebellum to the frontal supratentorial areas which subserve attentional and planning processes. This phenomenon of crossed cerebellar-cerebral diaschisis is supported by SPECT findings revealing a hypoperfusion in the anatomoclinically suspected brain regions. The constellation of cognitive, linguistic and behavioral symptoms adds new evidence to the multifaceted area of cerebellar neurocognition and demonstrates that the cerebellum might play a crucial role in cognitive, linguistic, and affective processing.     

Cerebellar agenesis II: motor and language functions

In a former study of a patient with cerebellar agenesis (HK) mild motor deficits, problems in delay eyeblink conditioning and mild to moderate deficits in IQ, planning behavior, visuospatial abilities, visual memory, and attention were found. The present study reports additional findings in the same patient. In the motor domain, impairments in fine motor manipulations, trace eyeblink conditioning and motor imagination in a functional magnetic resonance (fMRI) study were found. Based on fMRI findings; however, cortical areas involved in a tapping task did not significantly differ from a healthy control group. In the cognitive domain, deficits in speech comprehension as well as verbal learning and declarative memory were present. No significant affective symptoms were observed. Although problems in executive, visuospatial and language tasks are in agreement with the so-called cerebellar cognitive affective syndrome-other possibilities remain. Non-motor impairments in HK might also be a consequence of lacking motor abilities in development and motor deficits may interfere with the performance of parts of the cognitive tasks. In addition, lack of promotion and learning opportunities in childhood may contribute and mental retardation based on extracerebellar dysfunction cannot be excluded.     

Essential tremor--a neurodegenerative disorder associated with cognitive defects?

In the past decade, the hypothesis that essential tremor is a monosymptomatic tremorogenic disorder has been questioned. New clinical, neuroimaging, electrophysiological and pathological studies indicate that essential tremor is associated with subtle neurological deficits and could be considered a slowly progressive neurodegenerative disorder. The aim of this Review is to describe the nonmotor neurological symptoms that are commonly associated with essential tremor, and highlight the cognitive deficits associated with this condition. Several clinical studies have demonstrated that essential tremor is associated with mild deficits in attention, executive functions, memory and, possibly, other cognitive processes. Population-based surveys have confirmed that dysfunction in these cognitive domains affects patients both with severe and mild essential tremor. Clinical studies have also indicated that cognitive deficits associated with essential tremor are progressive and that patients with this condition have an increased risk of dementia. Mood and cognitive deficits commonly observed in patients with essential tremor are similar to symptoms of cerebellar cognitive affective syndrome. Further evidence is required from prospective studies to support the interpretation that essential tremor is a slowly progressive neurodegenerative disorder.     

A cognitive and affective pattern in posterior fossa strokes in children: a case series

Aim Posterior fossa strokes account for about 10% of ischaemic strokes in children. Although motor and dysautonomic symptoms are common, to our knowledge cognitive and affective deficits have not been described in the paediatric literature. Our aim, therefore, was to describe these symptoms and deficits. Method In a retrospective study, we included all cases of posterior fossa strokes in children occurring at a single centre between 2005 and 2007, and investigated cognitive and affective deficits. Results Five males aged 3 to 14 years met the inclusion criteria. They all presented very early with mood disturbances: outbursts of laughter and/or crying and alternating agitation or prostration that disappeared spontaneously within a few days. Persistent cognitive deficits were also diagnosed in all five: initial mutism, then anomia, followed by comprehension deficiency and deficiencies of planning ability, visual–spatial organization, and attention. Despite early and intensive rehabilitation, recovery from these cognitive deficits was slow and sometimes incomplete, and on follow‐up they proved to be more disabling than the motor symptoms. Interpretation These findings are similar to the cerebellar cognitive affective syndrome described in adults, and quite similar to the language and affective deficits observed in children after surgery for posterior fossa tumour. This is consistent with the role of the cerebellum and brainstem in affective and cognitive processes from early development.     

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.     

Frontal executive impairment associated with paraneoplastic cerebellar degeneration: a case study

Paraneoplastic cerebellar degeneration (PCD) is a rare cause of profound cerebellar dysfunction. Degenerative disorders of the cerebellum can cause cognitive and behavioral changes but the neuropsychological and behavioral sequelae of PCD are not well described. In this article, we detail selective frontal-executive disturbance, psychomotor slowing and affective change in a patient with PCD in whom there is no apparent extracerebellar involvement. The pattern of deficits suggests that PCD may be clinically dissociable from other forms of paraneoplastic encephalitis and correspond closely with the recently proposed "cerebellar-affective syndrome." The results underline the importance of the cerebellum in regulating cognitive function.     

Frontal Executive Impairment Associated With Paraneoplastic Cerebellar Degeneration: A Case Study

Paraneoplastic cerebellar degeneration (PCD) is a rare cause of profound cerebellar dysfunction. Degenerative disorders of the cerebellum can cause cognitive and behavioral changes but the neuropsychological and behavioral sequelae of PCD are not well described. In this article, we detail selective frontal-executive disturbance, psychomotor slowing and affective change in a patient with PCD in whom there is no apparent extracerebellar involvement. The pattern of deficits suggests that PCD may be clinically dissociable from other forms of paraneoplastic encephalitis and correspond closely with the recently proposed “cerebellar-affective syndrome.” The results underline the importance of the cerebellum in regulating cognitive function.     

Cognitive and affective disturbances in children after surgical treatment of cerebellar tumors

BACKGROUND AND PURPOSE: The cerebellum has been associated with motor control, but more recent studies have extended its contribution to other functions, such as modulation of emotions, behavioral organization or language. The cerebellar cognitive affective syndrome was described primarily in adults. In children, cerebellar lesions are relatively frequent and some are due to neoplasm. MATERIAL AND METHODS: Cognitive and emotional functions were studied in 66 children who underwent surgery for cerebellar pilocytic astrocytoma at the Department of Neurosurgery of the Children Memorial Health Institute. 36 children were psychologically examined and parents of 66 children filled in a questionnaire, answering questions about children's linguistic functioning, emotion regulation and ability to initiate, organize and efficiently realize various activities. RESULTS: The disturbances in the initiation and realization of activities were reported most often (77%). Problems in emotional regulation were noticed in 65% of children and were characterized by disinhibition, impulsivity and irritability. Language difficulties were observed in 42%. No significant differences between groups of children with different localization of tumor (vermis or cerebellar hemisphere) were observed. CONCLUSIONS: The present study confirms the psychological deficits following cerebellar lesion in children, similar to the cerebellar cognitive affective syndrome reported in adult patients.