Paravermal infarct and isolated cerebellar dysarthria

Theta burst stimulation over left cerebellum does not modulate auditory feedback control of vocal production

Background

Accumulating evidence has shown significant contributions of the right cerebellum to auditory-motor integration for vocal production. Whether the left cerebellum is likewise involved in vocal motor control, however, remains unclear.

Methods

By applying neuronavigated continuous and intermittent theta burst stimulation (cTBS/iTBS) over the left cerebellar lobule VII (Crus I), the present event-related potential (ERP) study investigated whether the left cerebellum exerts causal effects in modulating auditory feedback control of vocal pitch production. After receiving cTBS, iTBS, or sham stimulation over the left cerebellum, a group of fifteen young adults produced sustained vowels while hearing their voice unexpectedly shifted in pitch upwards or downwards by 200 cents. The effects of cerebellar stimulation were assessed by measuring the vocal and ERP (N1/P2) responses to pitch perturbations across the conditions.

Results

When compared to sham stimulation, cTBS or iTBS over the left cerebellar lobule VII (Crus I) led to no systematic changes in vocal compensations for pitch perturbations in auditory feedback. Also, the cortical N1/P2 responses did not vary significantly across the three stimulation sessions.

Conclusion

These findings present the first neurobehavioral evidence suggesting that the left cerebellum is not causally associated with auditory feedback control of vocal production. Together with previously reported causal effects of the right cerebellum in modulating vocal pitch regulation, the present study lends support to the hypothesis that there is a functional lateralization of the cerebellum in vocal motor control though auditory feedback.

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.

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.

MR Imaging Features of the Cerebellum in Adult-Onset Neuronal Intranuclear Inclusion Disease: 8 Cases

Neuronal intranuclear inclusion disease is a neurodegenerative disorder pathologically characterized by eosinophilic hyaline intranuclear inclusions. A high-intensity signal along the corticomedullary junction on DWI has been described as a specific MR imaging finding of the cerebrum in neuronal intranuclear inclusion disease. However, MR imaging findings of the cerebellum in neuronal intranuclear inclusion disease have not been fully evaluated. Here, we review MR imaging findings of the cerebellum in a series of 8 patients with pathologically confirmed neuronal intranuclear inclusion disease. The MR imaging results showed cerebellar atrophy (8/8 patients) and high-intensity signal on FLAIR images in the medial part of the cerebellar hemisphere right beside the vermis (the "paravermal area") (6/8) and in the middle cerebellar peduncle (4/8). The paravermal abnormal signals had a characteristic distribution, and they could be an indicator of the diagnosis of neuronal intranuclear inclusion disease even when using the results of past MR imaging examinations in which DWI findings were not examined.

Pure dysarthria and dysarthria-facial paresis syndrome due to internal capsule and/or corona radiata infarction

Background

Pure dysarthria (PD) and dysarthria-facial paresis syndrome (DFP) mainly result from lenticulostriate artery territory infarction. PD and DFP are rare clinical entities, often grouped without distinction. The purpose of this study was to examine clinical and radiographic differences between PD and DFP due to unilateral internal capsule and/or corona radiata infarction.

Methods

Using a database that included consecutive patients with ischemic stroke admitted to the neurological stroke units of three hospitals within 7 days from onset between September 2011 and April 2014, we retrospectively extracted first-ever stroke patient data, who presented with PD or DFP with a single ischemic lesion localized in the internal capsule and/or corona radiata. Patients with weakness, ataxia, sensory deficit, or cortical symptoms were excluded. Ischemic lesion volume was calculated by the ABC/2 method on diffusion-weighted imaging (DWI). DWI images were normalized and superimposed to the template for PD and DFP. We compared patients' characteristics between PD and DFP.

Results

A total of 2126 patients, including 65 patients (3.1 %) with PD or DFP, were registered. Of these, 13 PD patients and 18 patients with DFP due to unilateral internal capsule and/or corona radiata infarction were included for analysis. Compared with DFP patients, PD patients had longer onset-to-door time (median 37.5 vs. 10.8 h, p = 0.031), shorter vertical length (C component) of ischemic lesions (median 12.0 vs. 18.8 mm, p = 0.007), and smaller ischemic lesion volume (median 285 vs. 828 mm³, p = 0.023). Ischemic lesions causing PD were located more frequently in the left hemisphere than DFP (92 % vs. 56 %, p = 0.045). The superimposed lesion pattern indicated that DFP had lesions more medial and involving posterior portions of the putamen and the caudate body, as well as more of the genu and posterior limb of the internal capsule, than PD. Ninety days after onset, symptoms disappeared in 21 (72 %) out of 29 patients.

Conclusions

In cerebral infarction limited to the internal capsule and/or corona radiata, PD is derived from smaller and left-sided lesions with delay in diagnosis compared with DFP. The clinical course of those with PD and DFP might be benign.

Cerebellar mutism

INTRODUCTION

Cerebellar mutism (CM) is defined as a peculiar form of mutism that may complicate the surgical excision of posterior cranial fossa tumor. The incidence is variable in the literature, occurring in up to one third of cases in some series. Commonly occurring peculiar features of CM are delayed onset following surgery, limited duration, and spontaneous recovery usually associated with dysarthria.

METHODS

A review has been performed concerning anatomical substrates and circuits actually considered to be involved in the development of cerebellar mutism, as well as risk factors for its development that have been documented in the literature. Attention has also been given to the long-term prognosis and the possibilities of rehabilitation that can be considered in these children, which has been compared with the authors' institutional experience.

RESULTS AND CONCLUSIONS

Tumor infiltration of the brainstem seems to represent the most relevant feature related to the development of CM, along with the histological diagnosis of medulloblastoma. On the other hand, hydrocephalus does not represent an independent risk factor. The higher rate of CM in children seems to be related to the higher incidence in children of tumors with malignant histology and brain stem involvement. Surgical technique does not seem to have a definite role; in particular, the use of a telovelar approach as compared to vermian split to reach the fourth ventricle extension of the tumor has not been demonstrated to prevent the development of cerebellar mutism. Concerning long-term prognosis, around one third of the children who develop cerebellar mutism after surgery have a persistent dysarthria, the remaining ones showing a residual phonological impairment. Long-term dysarthric features tend to be more severe and less prone to recovery in children presenting at diagnosis with associated combined procedural memory and defective neurocognitive functions.

Language Disorders due to Posterior System Strokes - An Ignored Dysfunction

The anterior system is primarily responsible for the clinical picture in a patient that presents with clinical aphasia. However, recent reports have shown that injuries to posterior structures, the cerebellum in particular, may have a role in language processing. Herein, we will look first at the linguistic role of the cerebellum in light of the literature, then of the thalamus and some described clinical syndromes, and finally, specific syndromes resulting from occipital lobe lesions, all of which are supported by the posterior vascular system. The human brain is such a complex organization that in addition to the thalamus and occipital cortex, we can see the involvement of the cerebellum in high cognitive functions. Posterior system strokes may lead to clinical findings of cognitive deficits, including neurolinguistic components. Determining these defects in stroke patients may precipitate changes in current management strategies.

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.

Auditory-perceptual speech analysis in children with cerebellar tumours: a long-term follow-up study

Mutism and Subsequent Dysarthria (MSD) and the Posterior Fossa Syndrome (PFS) have become well-recognized clinical entities which may develop after resection of cerebellar tumours. However, speech characteristics following a period of mutism have not been documented in much detail. This study carried out a perceptual speech analysis in 24 children and adolescents (of whom 12 became mute in the immediate postoperative phase) 1-12.2 years after cerebellar tumour resection. The most prominent speech deficits in this study were distorted vowels, slow rate, voice tremor, and monopitch. Factors influencing long-term speech disturbances are presence or absence of postoperative PFS, the localisation of the surgical lesion and the type of adjuvant treatment. Long-term speech deficits may be present up to 12 years post-surgery. The speech deficits found in children and adolescents with cerebellar lesions following cerebellar tumour surgery do not necessarily resemble adult speech characteristics of ataxic dysarthria.

The cerebellum and neuropsychological functioning: a critical review

The cerebellum, while once considered a brain region principally involved in motor control and coordination, is increasingly becoming associated with a range of neuropsychological and neuropsychiatric presentations. This paper reviews the dominant neuropsychological domains and neuropsychiatric conditions for which cerebellar involvement has been demonstrated, including visuospatial functioning, learning and memory, language, executive functioning, attention-deficit/hyperactivity disorder, autism spectrum disorders, and schizophrenia. The paper concludes with a discussion of a potential neuropsychological localization model within the cerebellum and a discussion of prognosis and rates of recovery that can be expected, following localized cerebellar lesions.

Cerebellar ataxia: pathophysiology and rehabilitation

This series of articles for rehabilitation in practice aims to cover a knowledge element of the rehabilitation medicine curriculum. Nevertheless they are intended to be of interest to a multidisciplinary audience. The competency addressed in this article is 'The trainee consistently demonstrates a knowledge of management approaches for specific impairments including spasticity, ataxia.'

[Cerebellar infarction]

Cerebellar infarction can be difficult to diagnose because the clinical picture is often dominated by fairly non-specific symptoms, which are more indicative of a benign condition. When cerebellar infarction affects the brainstem, the semiology is richer, and pure cerebellar signs are rendered less important. A perfect knowledge of the organisation of the cerebellar artery territories is required, regardless of the infarct topography. This knowledge is essential for making an accurate diagnosis, understanding the mechanisms and organising a treatment plan. Clinical algorithms for the treatment of dizziness, headaches and vomiting would improve the selection of candidates for brain imaging. Thus, the early identification of patients with a high risk of subsequent deterioration would lead to a better prognosis in cases of cerebellar artery territory infarction.

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.

Superior cerebellar artery infarction in endovascular treatment for tentorial dural arteriovenous fistulas

BACKGROUND

Superior cerebellar artery (SCA) syndrome shows ipsilateral cerebellar ataxia and Horner's syndrome, contralateral superficial sensory disturbance, as well as nystagmus toward the impaired side, vertigo, and nausea. Occasionally, unilateral lesions may produce bilateral hypogeusia and contralateral hypoacusia.

OBJECTIVE

To report 2 patients with unilateral lower midbrain ischemic lesions of the inferior colliculus level caused by transarterial embolization for tentorial dural arteriovenous fistulas (TDAVFs).

METHODS

Hospital records for 21 patients with TDAVFs mainly treated by endovascular techniques between 2005 and 2008 were reviewed. Two patients with MRI evidence of unilateral SCA territory infarction were investigated.

RESULTS

Of 21 patients, 2 treated transarterially with Onyx-18 (a nonahesive liquid embolic agent) developed infarctions in the territory of SCA. One patient had lateral SCA infarction characterized by ipsilateral gait ataxia, contralateral hemihypoesthesia, with additional ipsilateral ocular motor palsy and bilateral gustatory loss. And the other patient had medial SCA infarction characterized by ipsilateral ataxia contralateral hemihypoesthesia with additional contralateral hypoacusia.

CONCLUSION

SCA infarction can be caused by transarterial injection of Onyx-18 via SCA or the posterior cerebral artery (PCA) for TDAVFs and additionally presented with gustatory loss and deafness, which is generally not a feature of the SCA syndrome.

Clinical study of the responsible lesion for dysarthria in the cerebellum

There have been few reports describing the lesion for cerebellar dysarthria. We compared MRI findings of 4 reported patients (including our previously reported patient) to that of our patient who showed ataxic speech and ataxic gait. The lesions of 4 patients involved lobulus quadrangularis and lobulus simplex, and the lesion of the present patient involved lobulus semilunaris superior and lobulus simplex. Since lobulus simplex and lobulus quadrangularis were involved in many patients, we speculated that the cerebellar dysarthria of the present patient was due to the damage of these areas in the upper cerebellum.

Evaluation of language functions in acute cerebellar vascular diseases

BACKGROUND

The principal features of the cerebellar infarcts are ataxia, failure of coordination, gait instability, and articulation and eye movement disabilities. Language disabilities are also seen with cerebellar lesions, but there are difficulties in diagnosis. This study was planned to evaluate the effects of cerebellar lesions on language functions and the relation between these functions and lesion type, age, and education level.

METHODS

A total of 20 patients, 13 male (65%) and 7 female (35%), were included in this study. Twenty control subjects with similar demographic characteristics were also included. The mean age of the patient group was not statistically different.

RESULTS

Patients with vermal lesions had significantly higher performance than patients with paravermal lesions when evaluating the understanding of hearing and total aphasia score. Understanding of reading function was significantly better in the patients with small lesions compared with those with large lesions. When the aphasia parameters were compared between the patient and control groups, significant differences were found for all parameters, which reflected the language abilities understanding, naming, true-wrong questions, complex questions, comparing, repeating, and total aphasia score. Reading and writing functions were also significantly different between the patients and the control subjects.

CONCLUSION

We found that the cerebellum contributes in several language parameters. These functions show difference according to localization and lesion volume of cerebellar disease. Aphasia should be explored as an important parameter when evaluating the loss of function in patients with cerebellar lesions.

Long-term neuromotor speech deficits in survivors of childhood posterior fossa tumors: effects of tumor type, radiation, age at diagnosis, and survival years

The cerebellum is important for the coordination of fluent speech. The authors studied how childhood cerebellar tumors affect long-term neuromotor speech outcomes, including the relation between outcome and tumor type, radiation, age at diagnosis, and survival years. Videotaped speech samples of child and adult long-term survivors of childhood cerebellar astrocytoma (nonradiated) and medulloblastoma (radiated) tumors and healthy controls were analyzed by 2 speech pathologists for ataxic dysarthria, dysfluency, and speech rate. Ataxia varied with tumor type/radiation. Medulloblastoma survivors had significantly more ataxic dysarthric features than either survivors of astrocytomas or controls, who did not differ from each other. Dysfluency varied with a history of a posterior fossa tumor. Medulloblastoma and astrocytoma survivors were each significantly more dysfluent than controls but did not differ from each other. Speech rate varied with age and tumor type. Adult controls were significantly faster than child controls, although adult tumor survivors were comparable to their child counterparts. Adult controls had significantly faster speech rates than adult survivors of medulloblastoma tumors. Ataxic dysarthric speech characteristics are more frequent in radiated survivors of medulloblastoma tumors than nonradiated survivors of astrocytoma tumors. Dysfluent and slow speech occur in cerebellar tumor survivors, regardless of tumor type and radiation history. Cerebellar tumors in childhood limit speech rate in adulthood.

The neural basis of ataxic dysarthria

Lesions to the cerebellum often give rise to ataxic dysarthria which is characterized by a primary disruption to articulation and prosody. Converging evidence supports the likelihood of speech motor programming abnormalities in addition to speech execution deficits. The understanding of ataxic dysarthria has been further refined by the development of neural network models and neuroimaging studies. A critical role of feedforward processing by the cerebellum has been established and linked to speech motor control and to aspects of ataxic dysarthria. Moreover, this research has helped to define models of the cerebellar contributions to speech processing and production, and to posit possible regions of speech localization within the cerebellum. Bilateral, superior areas of the cerebellum appear to mediate speech motor control while a putative role of the right cerebellar hemispheres in the planning and processing of speech has been suggested.

Dysarthria due to Supratentorial and Infratentorial Ischemic Stroke: A Diffusion-Weighted Imaging Study

BACKGROUND AND PURPOSE

Dysarthria characterized by slurring with imprecise articulation without evidence of aphasia is a frequent symptom in the acute phase of cerebral ischemia, although there is little knowledge on its anatomic specificity and spectrum of associated clinical characteristics regarding diffusion-weighted imaging (DWI).

METHODS

An investigation of 101 consecutive patients with sudden-onset dysarthria due to a single or multiple lesions on DWI, corresponding to 8.7% of 1,160 patients with ischemic stroke, was made. The presence of lesions of the cranial arteries was sought by magnetic resonance angiography and reviewed with a three-dimensional rotating cineangiographic method.

RESULTS

Dysarthria was mostly associated with a supratentorial lesion (63%) and with a classic lacunar stroke syndrome in 45% of patients. Lacunar lesions on DWI were found in 69 (68%) patients, while only 45 of the patients (65%) with a lacunar infarct presented a classic lacunar syndrome with dysarthria. Pure dysarthria occurred in 15% of patients, dysarthria + pure motor hemiparesis in 14%, dysarthria + ataxic hemiparesis in 11%, dysarthria + clumsy hand syndrome in 7%, dysarthria + pure sensory stroke in 3%, dysarthria + central facial paresis in 8% and lingual paresis occurred in 2%. The lesions were due to small-artery disease in 41%, large-artery disease in 15%, cardioembolism in 10% and a mixed etiology in 3%. The cause of stroke was not identified in 17 patients. Lesions on DWI were found mainly in the corona radiata (n = 18), middle cerebral artery territory, including the motor cortex and/or insular cortex (n = 13), striatocaudate nuclei (n = 11), primary motor cortex (n = 10), internal capsule (n = 7), pons (n = 25), pontobulbar junction (n = 5) and the thalamomesencephalic junction (n = 4). Isolated cerebellar infarctions (n = 6) or associated brainstem lesions (n = 6) affected mostly the superior cerebellar artery or the posterior inferior cerebellar artery territory.

CONCLUSION

Cortical involvement was more frequent in patients with pure dysarthria than those with dysarthria and additional neurological signs, while the frequency of pontine involvement was higher in patients with additional neurological signs than those with pure dysarthria. One third of the patients with dysarthria had multiple lesions on DWI, and the most common cause of stroke was small-artery disease. Pure dysarthria, dysarthria with lingual paresis, dysarthria with clumsy hand and dysarthria with facial paresis had predictive value for lacunar lesions.

Isolated body lateropulsion caused by a lesion of the rostral vermis

A 66-year-old man presented with axial lateropulsion, exhibiting sudden falling as the sole clinical sign of cerebellar infarction in the territory of the medial branch of the superior cerebellar artery (mSCA). A brain MRI showed acute infarction selectively involving the centralis of the rostral vermis. This patient illustrates that cerebellar infarction in the territory of the mSCA can present as an isolated body lateropulsion. The possible mechanism of an isolated body lateropulsion is considered.

Left-hemispheric dominance for articulation: a prospective study on acute ischaemic dysarthria at different localizations

Dysarthria is a frequent symptom in cerebral ischaemia. However, speech characteristics of these patients have not previously been investigated in relation to lesion site in a prospective study. We investigated the auditory perceptual features in 62 consecutive patients with dysarthria due to a single, non-space-occupying cerebral infarction confirmed by MRI. Standardized speech samples of all patients were stored within 72 h after stroke onset using a digital tape recorder. Speech samples were assessed independently by two experienced speech therapists, who were unaware of the clinical and neuroradiological findings, using an interval scale ranging from 0 to 6. Separately assessed were features of articulation, phonation, prosody, and the global severity for a total of 31 items. Extracerebellar infarctions (85.5%) were located in the lower motor cortex (14.5%), striatocapsular region (46.8%) and base of the pons (24.2%). Isolated cerebellar infarctions were present in 14.5% of patients. There was a strong correlation between the findings of both examiners, showing identical scores, or only minor differences (<1 on the assessment scale) for 80% of all items. The average severity of dysarthria was 2.9 +/- 1.3. Articulatory abnormalities were the predominant deviation characteristics, affecting in particular the production of consonants. However, phonatory and prosodic abnormalities were also frequently observed speech characteristics. As revealed by factor analysis of speech characteristics the total severity of dysarthria was mainly influenced by the impairment of articulation. Speech parameters describing characteristics of articulation and prosody showed significant side-to-side and area differences, while this effect was lacking for any voice parameter. Left cerebral lesions showed a more severe overall impairment of speech and articulation, independent of lesion topography. Thirty-eight of 62 patients were available for follow-up. Speech evaluation showed normal speech within weeks in 15 out of 38 patients (39.5%). In the other 23 patients overall severity of dysarthria was mild. This is the first prospective study which describes speech characteristics of dysarthria due to acute unilateral cerebral infarctions. We could demonstrate that dysarthria in extracerebellar infarctions was more frequently caused by left-sided lesions and that the severity of dysarthria was more pronounced in left-sided lesions independent from lesion topography. All extracerebellar lesions were located along the course of the cortico-bulbar tract fibres. Compatible with a common pathophysiological basis of dysarthria in these patients, none of the 31 speech items differed significantly between subcortical and brainstem lesions.

Functional localization in the human cerebellum based on voxelwise statistical analysis: a study of 90 patients

The aim of the present study was to examine somatotopy in the cerebellar cortex and a possible differential role of the cerebellar cortex and nuclei in functional outcome. Clinical findings and 3D MRI-based cerebellar lesions site were compared in a group of 90 patients with focal cerebellar lesion using International Cooperative Ataxia Rating Scale (ICARS) and voxel-based lesion-symptom mapping (VLSM). Separate analysis was performed in patients with acute and chronic ischemic lesions (n=43) and patients with acute and chronic surgical lesions (n=47). Thirty-eight patients were included after resection of a cerebellar tumor in childhood or adolescence. The most significant lesion symptom correlations were observed in the subgroup with acute ischemic lesions. Limb ataxia was significantly correlated with lesions of the interposed (NI) and part of the dentate nuclei (ND), ataxia of posture and gait with lesions of the fastigial nuclei (NF) including NI. Correlations with cortical lesions were less significant and present in the superior cerebellum only. Upper limb ataxia was correlated with lesions of vermal, paravermal and hemispheral lobules IV-V and VI, lower limb ataxia with lesions of vermal, paravermal and hemispheral lobules III and VI, dysarthria with lesions of paravermal and hemispheral lobules V and VI and ataxia of posture and gait with lesions of vermal and paravermal lobules II, III and IV. In the subgroups with chronic focal lesions, similar correlations were observed with lesions of the cerebellar nuclei, but significantly less correlations with lesions of the cerebellar cortex. Functional localization based on VLSM backs findings in previous animal and functional brain images studies in healthy human subjects. The lesion site appears to be critical for motor recovery. Lesions affecting the cerebellar nuclei are not fully compensated at any age and independent of the pathology in humans.

Incidence of dysarthria in children with cerebellar tumors: a prospective study

The present study investigated dysarthric symptoms in children with cerebellar tumors. Ten children with cerebellar tumors and 10 orthopedic control children were tested prior and one week after surgery. Clinical dysarthric symptoms were quantified in spontaneous speech. Syllable durations were analyzed in syllable repetition and sentence production tasks. Localization of the cerebellar lesions were defined after manual transfer from individual 2D-MR images onto 3D images of a spatially normalized healthy brain. Cerebellar children showed few and mild clinical signs of dysarthria. No difference was present in the sentence production task compared to controls. In five cerebellar children, syllables were prolonged in the syllable repetition task after surgery. Syllable duration normalized in an additional four-week session in all but one case. The MR-analysis showed that superior paravermal cerebellar areas likely involved in dysarthria in adults (paravermal lobules HVI, Crus I) were not significantly affected. In children, speech impairments appear to be rare after cerebellar surgery because tumors most commonly affect posterior-inferior and medial parts of the cerebellum while critical cerebellar regions are likely spared. The results suggest a similar localization of speech functions in the cerebellum in children and adults.

Cerebellar mutism

The aim of the present study was to investigate the manifestations of mutism after surgery in children with cerebellar tumors. Speech impairment following cerebellar mutism in children was investigated based on standardized acoustic speech parameters and perceptual criteria. Mutistic and non-mutistic children after cerebellar surgery as well as orthopedic controls were tested pre-and postoperatively. Speech impairment was compared with the localization of cerebellar lesions (i. e. affected lobules and nuclei). Whereas both control groups showed no abnormalities in speech and behavior, the mutistic group could be divided into children with dysarthria in post mutistic phase and children with mainly behavioral disturbances. In the mutistic children involvement of dentate and fastigial nuclei tended to be more frequent and extended than in the nonmutistic cerebellar children. Cerebellar mutism is a complex phenomenon of at least two types. Dysarthric symptoms during resolution of mutism support the anarthria hypothesis, while mainly behavioral changes suggest an explanation independent from speech motor control.

The lateralized linguistic cerebellum: a review and a new hypothesis

During the past 2 decades the collaboration across disciplines and the methodologic and conceptual advances of contemporary neuroscience have brought about a substantial modification of the traditional view of the cerebellum as a mere coordinator of autonomic and somatic motor functions. Growing insights in the neuroanatomy of the cerebellum and its interconnections, evidence from functional neuroimaging and neurophysiological research, and advancements in clinical and experimental neuropsychology have established the view that the cerebellum participates in a much wider range of functions than conventionally accepted. This increase of insight has brought to the fore that the cerebellum modulates cognitive functioning of at least those parts of the brain to which it is reciprocally connected. This article reviews the recently acknowledged role of the cerebellum in cognition and addresses in more detail experimental and clinical data disclosing the modulatory role of the cerebellum in various non-motor language processes such as lexical retrieval, syntax, and language dynamics. In agreement with the findings indicating a topographical organization of the cerebellar structures involved in language pathology we advance the concept of a "lateralized linguistic cerebellum." In our view crossed cerebral diaschisis processes, reflecting a functional depression of supratentorial language areas due to reduced input via cerebellocortical pathways, might represent the relevant pathomechanism for linguistic deficits associated with cerebellar pathology.

Clinicoanatomic studies in dysarthria: review, critique, and directions for research

More than 30 years ago, Darley, Aronson, and Brown (1969) proposed clinicoanatomic correlations for seven perceptual types of dysarthria. These correlations have not been systematically re-examined even though imaging technologies developed in recent years provide the means to do so. This review considers data from published imaging studies as well as data from selected medical interventions to evaluate the current state of knowledge that relates lesion site to the nature of a speech disturbance. Although the extant data are not sufficient to allow a complete evaluation of the seven types of dysarthria described by Darley et al., relevant information has been reported on lesions of the pyramidal pathway, extrapyramidal pathway, and cerebellum. In general, the results are best explained by an equivalence mode of brain-behavior relationship in which a type of dysarthria is associated with a lesion in one of two or more brain structures. Criteria also are proposed for future studies of clinicoanatomic relationships in neurogenic communication disorders.

Isolated dysarthria caused by a right paravermal infarction

Images

Isolated cerebellar dysarthria associated with a heat stroke

Patients presenting with heat stroke may develop an acute pancerebellar syndrome. A patient presenting with an isolated cerebellar dysarthria after a heat stroke is reported. The dysarthria lasted two weeks. An isolated cerebellar dysarthria has been previously described in lesions of the paravermal zone of the rostral cerebellum. It is suggested that this region of the cerebellum is particularly vulnerable to fever.

Isolated lateropulsion of the trunk in cerebellar infarct

MRI in a 63-year-old male with isolated lateropulsion of the trunk disclosed an infarct in the inferior portion of the right cerebellar hemisphere, suggesting an end-zone type infarct in the lateral branch of the right posterior inferior cerebellar artery (1PICA) or a borderzone infarct between 1PICA and superior cerebellar artery. A close clinico-topographical relationship between isolated lateropulsion of the trunk and lesion in the territory of 1PICA was demonstrated.

Cerebellar infarction. Clinical and anatomic observations in 66 cases

BACKGROUND AND PURPOSE

Cerebellar infarction displays different clinical features, depending on the vascular territory involved. We studied patients with infarcts in the territories of the posterior inferior cerebellar artery or the superior cerebellar artery to compare their clinical presentation, course, and prognosis.

METHODS

We retrospectively analyzed the clinical features, laboratory data, and imaging studies of 66 patients with cerebellar infarction collected consecutively at five institutions. All the cerebellar infarcts were documented on computed tomographic scan or magnetic resonance imaging.

RESULTS

Two distinct profiles emerged, depending on the vascular territory involved. In 36 patients with posterior inferior cerebellar artery territory infarcts, a triad of vertigo, headache, and gait imbalance predominated at stroke onset. Computed tomography showed severe cerebellar mass effect in 11 cases (30%), with associated hydrocephalus in seven. In these seven patients (19%), postinfarct swelling led to brain stem compression that resulted in four deaths. In 30 patients with superior cerebellar artery infarcts, gait disturbance predominated at onset; vertigo and headache were significantly less common. The clinical course was usually benign. Computed tomography showed marked cerebellar mass effect, hydrocephalus, and brain stem compression in only two instances (7%). Presumed cerebral embolism was the predominant stroke mechanism in patients with superior cerebellar artery distribution infarcts, whereas in those with posterior inferior cerebellar artery distribution infarcts, the stroke mechanism was equally divided between cardiogenic embolism and posterior circulation arterial disease.

CONCLUSIONS

Cerebellar infarcts in the posterior inferior cerebellar artery and superior cerebellar artery distribution have distinct differences in clinical presentation, course, and prognosis. These differences should help in the selection of appropriate monitoring and treatment strategies.

Transient loss of speech followed by dysarthria after removal of posterior fossa tumour

The authors report three children who suffered transient loss of speech during six to eight weeks following removal of a large midline cerebellar tumour. None manifested speech difficulties immediately after surgery, but all developed mutism within 24 to 48 hours. The speech of all children slowly but completely recovered, after a period of severe dysarthria. The re-organization of speech functions is discussed in relation to the functioning of musculature.