Cerebellar mutism

Cerebellar mutism occurs in about 25% of children following posterior fossa tumor surgery. It is usually accompanied by other neurological and behavioral disturbances. Mutism is transient in nature lasting several days to months and is frequently followed by dysarthria. In addition, impairment of language and other neuropsychological functions can be found after long term follow up in the majority of patients. The pathophysiological background of mutism may be higher speech dysfunction mediated by crossed cerebello-cerebral diaschisis which is frequently found during the mute period. Foremost injury to the bilateral dentatothalamocortical tract appears to be critical for the development of cerebello-cerebral diaschisis and subsequent mutism. Direct cerebellar injury is the likely reason for persisting deficits after the mute period. Minimization of injury to the dentatothalamocortical tract during surgery may be promising in the prevention of mutism. While there is no established treatment of mutism, early speech and rehabilitation therapy is recommended.     

Role of cerebellum in fine speech control in childhood: persistent dysarthria after surgical treatment for posterior fossa tumour

Dysarthria following surgical resection of childhood posterior fossa tumour (PFT) is most commonly documented in a select group of participants with mutism in the acute recovery phase, thus limiting knowledge of post-operative prognosis for this population of children as a whole. Here we report on the speech characteristics of 13 cases seen long-term after surgical treatment for childhood PFT, unselected for the presence of post-operative mutism (mean time post-surgery = 6y10 m, range 1;4-12;6 years, two had post-operative mutism), and examine factors affecting outcome. Twenty-six age- and sex- matched healthy controls were recruited for comparison. Participants in both groups had speech assessments using detailed perceptual and acoustic methods. Over two-thirds of the group (69%) with removal of PFT had a profile of typically mild dysarthria. Prominent speech deficits included consonant imprecision, reduced rate, monopitch and monoloudness. We conclude that speech deficits may persist even up to 10 years post-surgery in participants who have not shown mutism in the acute phase. Of cases with unilateral lesions, poorer outcomes were associated with right cerebellar tumours compared to left, consistent with the notion based on adult data that speech is controlled by reciprocal right cerebellar/left frontal interactions. These results confirm the important role of the cerebellum in the control of fine speech movements in children.     

The neural circuitry of conversion disorder and its recovery

Little is understood about neural networks associated with conversion disorders. This case study reports the first investigation of the neural circuitry associated with the recovery of chronic conversion disorder. A patient with a four year history of hysterical mutism was assessed with functional MRI (fMRI) during a vocalization task, and then provided psychotherapy that attempted to reduce motivational factors that maintained mutism. The patient resumed full speech, and was readministered the fMRI vocalization task. Vocalization during mutism and following recovery of speech resulted in increases in speech-related networks, including the inferior frontal gyrus (IFG), middle frontal, and supplementary motor area of the frontal cortex, temporal and parietal cortices, and also in the primary and sensory motor regions. Following speech recovery but not during mutism, the IFG was correlated positively with the anterior cingulate cortex and negatively with the amygdala. This pattern suggests that during the conversion disorder there was impaired connectivity between speech networks and networks that regulate anxiety.     

Mutism associated with buccofacial apraxia and bihemispheric lesions

Mutism following brain trauma is quite common, is usually transient, and recovery of speech is essentially the rule. Lasting total absence of speech without aphasia is highly unusual. Three such patients, two of traumatic and one due to vascular origin showing buccofacial apraxia (BFA) and computerized tomography (CT) evidence of bilateral frontal lesions are reported. It is suggested that complete lasting mutism associated with BFA is a result of bihemispheric lesions affecting mainly the opercular part of the inferior frontal gyrus and immediate adjacent regions.     

Elective mutism in children: A family systems approach

Abstract

Elective mutism in children is a relatively rare symptom which is more prevalent in the kindergarten population and has a higher incidence among immigrant families. Treatment strategies for this silent symptom include speech therapy, behavior modification, psychoanalytic, psychotherapeutic, family systems and a combination of these approaches. This paper reviews the types of elective mutism and proposes common characteristics of elective mutists' families. The potential for a redefinition of the term “elective mutism” is examined. It is concluded that family dynamics are an integral part of the elective mutism problem and need to be considered in a comprehensive treatment plan.     

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.     

Two sets of twins with selective mutism: neuropsychological findings.

Neuropsychological data are reviewed from two sets of dizygotic twins presenting with selective mutism characterized by situation specific anxiety, extreme passive behavior, lack of responsivity, lack of peer interaction, and a chronic course of selective mutism. Both sets of twins had a history of prematurity and delayed speech development. One set of twins presented with normal intelligence and normal receptive language skills but with expressive language and oral motor sequencing difficulties. The second set of twins presented with Verbal IQ deficits and significant receptive and expressive language deficits. A summary of current conceptualizations regarding etiology and treatment of selective mutism is provided.     

A Controlled Single-Case Treatment of Severe Long-Term Selective Mutism in a Child With Mental Retardation

The aim of the present study was to demonstrate the efficacy of combining two operant learning procedures—shaping and fading—for treating selective mutism. The participant was a 12-year-old boy with mental retardation presenting a severe long-term selective mutism. The treatment was aimed at increasing the loudness of his vocalizations in an increasingly social milieu. The treatment was conducted over the course of about 20 weeks, with four 15-minute sessions per week. A gradual increase in speech loudness was observed. Data indicated a close correspondence between the changes in speech loudness and the criteria for reinforcement successively applied by the therapist, thereby confirming the causal link between the child's progress and the changes in reinforcement contingencies. In addition, good generalization was noted during the stimulus fading phase. Six-month follow up showed that loudness of verbalizations was still satisfactory in the classroom despite a change of school and peer group. The impressive improvement of the child's verbal behavior shows that the implementation of a treatment package including both shaping and stimulus fading is a worthwhile therapeutic option, even in the case of severe long-term selective mutism associated with mental retardation.     

Pure mutism due to simultaneous bilateral lenticulostriate artery territory infarction

A case of pure mutism without pseudobulbar palsy and other neurological findings resulting from simultaneous bilateral lenticulostriate artery territory infarction is presented. A 45-year-old woman suffered a transient ischemic attack with nonfluent aphasia and right hemiparesis. Six months later, she developed pure mutism without oral apraxia, pseudobulbar signs, and motor deficits. Magnetic resonance imaging revealed bilateral infarction in the lentiform nucleus regions. In the available data, there is only one report of simultaneous bilateral lenticulostriate infarction. To date, in all reported cases of mutism of subcortical vascular origin there are also various degrees of pseudobulbar signs and motor deficits and the responsible lesions are mostly consecutive. The case presented here is the first to show pure vascular mutism without other neurological findings.     

Left thalamic hemorrhage with dysphasia: a report of five cases.

A specific type of “thalamic speech” is being recognized with increasing frequency. Paucity of spontaneous speech, fading vocal volume, anomia, perseveration, and neologisms, with intact comprehension and word repetition, characterize the speech disorder associated with thalamic lesions. Nine cases of left thalamic hemorrhage and speech disturbance have been reported previously. This report details the speech, neurological, and neuroradiological findings in five additional cases of thalamic hemorrhage with dysphasia.     

Task-related factors in oral motor control: speech and oral diadochokinesis in dysarthria and apraxia of speech

This study was focused on the potential influence of task-related factors on oral motor performance in patients with speech disorders. Sentence production was compared with a nonspeech oral motor task, i.e., oral diadochokinesis. Perceptual and acoustic measures of speech impairment were used as dependent variables. Between-task comparisons were made for subsamples of a population of 140 patients with different motor speech syndromes, including apraxia of speech and cerebellar dysarthria. In a further analysis subgroups were matched for speaking rate. Overall, dysdiadochokinesis was correlated with the degree of speech impairment, but there was a strong interaction between task type and motor speech syndrome. In particular, cerebellar pathology affected DDK to a relatively greater extent than sentence production, while apraxic pathology spared the ability of repeating syllables at maximum speed.     

Assessment and Treatment of Selective Mutism

Abstract

We present the results of a stimulus fading procedure used to treat a six-year-old girl who met DSM-DJ-R criteria for elective mutism (now Selective Mutism in DSM-IV). An assessment protocol is presented that features procedures that can be used to render a diagnosis and assist in treatment planning. A treatment program was implemented through a consultation process that required close monitoring and revision over several months. Results of the case study suggested that the stimulus fading of new persons into the school setting was effective in producing speech. Future re-search directions in assessment and treatment of selective mutism are discussed.     

Progressive catatonia

We present the case of a young man with a diagnosis of a childhood-onset pervasive developmental disorder who developed a progressive neurologic deterioration with persistent catatonia and right hemiparesis. On his initial evaluation approximately three years after the onset of mutism, he manifested right hemiparesis and catalepsy. Two years later, although catalepsy had subsided, motor function had deteriorated so that he could not use his hands to feed or dress himself. Oral-facialbuccal dyskinesia manifested by blepharospasm and grimacing were present constantly during waking hours. Quantitative electroencephalography demonstrated markedly decreased amplitude, a finding associated with catatonia. Left sural nerve biopsy indicated large axon cylinder degeneration. Left deltoid biopsy demonstrated perimysial fibrosis and type II fiber predominance. Although magnetic resonance imaging of the head without contrast was normal, positron emission tomography indicated hypometabolism of the right cerebral and the right cerebellar hemispheres. The patient continues to deteriorate despite a course of 25 electroconvulsive treatments. He continues to manifest criteria for catatonia including motoric immobility, mutism, and peculiarities of voluntary movement such as prominent grimacing. We suspect an inherited neurodegenerative disorder. Since catatonia is a treatable condition frequently associated with medical and neurological diseases, examination for the features of catatonia must be included in the assessment of patients with progressive brain degeneration. This report is an attempt to clarify the traits of a serious variant of progressive brain degeneration.     

On the role of the anterior cingulate cortex in phonation: A case report

A 41-year-old male patient is presented with a lesion in the anterior cingulate cortex, medial orbital cortex, and rostral striatum bilaterally and supplementary motor area on the left side. The patient first exhibited a state of akinetic mutism which lasted about 6 weeks. During this state, no volitional vocal utterances were made; there were, however, occasional groans of pain. During recovery, the mute phase was replaced by a state in which the patient could whisper but not phonate verbal utterances. About 10 weeks after the accident, phonation was restored. The speech was characterized, however, by monotonous intonation and a very low frequency of spontaneous utterances. While the frequency of spontaneous speech improved noticeably during the following months, emotional intonation remained permanently defective. A comparison of the present case with other cases from the literature as well as experimental monkey data suggest that the anterior cingulate cortex is involved in the volitional control of emotional vocal utterances.     

Speech motor deficits in cerebellar infarctions

Functional imaging studies demonstrated cerebellar activation during speech movements in the rostral cerebellar region. Ischemic lesions of this area, which is supplied by the superior cerebellar artery, induce dysarthria.     

Aphasia following a right thalamic hemorrhage

A left-handed patient with a right thalamic hemorrhage and disordered speech is described. Sequential examinations and aphasia testing were done during a 1-year follow-up period and the results are reported. This case supports those authors who have described characteristics they feel are helpful in diagnosing disordered speech associated with thalamic lesions. Paucity of speech, reduced voice volume, anomia, some paraphasia, and severe dysgraphia were present, but comprehension and repetition were relatively preserved. She showed modest improvement with time. This case also confirms that thalamic involvement in speech is a dominant, rather than a specifically left hemispheric function.     

The communication disorder in dialysis dementia: A case report

The communication disorder in dialysis dementia is an integral feature of the syndrome. This report describes the communication disorder in a 67-year-old man over a period of 4 months from his admission to the hospital to his death. In the early stage of the syndrome, the most prominent feature was a speech problem, the characteristics of which may vary among cases. In the middle stage, it was difficult to distinguish among aphemia, aphasia, or a combination of dysarthria and confusional state. The severity of the problems in these stages was temporally related to the dialysis treatments. The final stage was characterized by constant mutism and was unrelated to the dialysis treatments. Death occurred 10 months after the communication problems emerged. Communication studies of dialysis dementia patients may offer a systematic method to monitor the course of the syndrome, its response to therapeutic trials, and a clinical model for the study of communication disorders in general.     

Speech disturbances in presenile dementia related to local cerebral blood flow abnormalities in the dominant hemisphere

Ten female patients, age 50–70 years, suffering from presenile dementia and showing signs of defective speech function were analyzed. All patients underwent measurements of regional cerebral blood flow (rCBF) by the xenon clearance technique using a 32-detector piece of equipment, and all showed a marked reduction of the hemisphere mean blood flow level. In addition, regional decreases of blood flow of the gray matter was demonstrated. Patients with a marked reduction in the temporo-parieto-occipital regions showed signs of receptive aphasia including alexia and agraphia. Patients with a marked frontal reduction showed signs of expressive aphasia of various types including stereotyped language, voluble speech, echolalia, and mutism in later stages. The results give further support to our previous conclusion that subsymptoms of presenile dementia, apparently also speech disturbances, can be related to local degenerative changes in the brain, which in their turn are accompanied by local reductions of the blood flow of the gray matter. There is pathoanatomical evidence to support this conclusion.     

Phonemic vowel length contrasts in cerebellar disorders

Apraxia of speech and Broca's aphasia both affect voice onset time (VOT) whereas phonemic vowel length distinctions seem to be preserved. Assuming a close cooperation of anterior perisylvian language zones and the cerebellum with respect to speech timing, a similar profile of segment durations must be expected in ataxic dysarthria. In order to test this hypothesis, patients with cerebellar atrophy or cerebellar ischemia were asked to produce sentence utterances including either one of the German lexial items "Rate" (/ra:t(h)e/, 'installment'), "Ratte" (/rat(h)e/, 'rat'), "Gram" (/gra:m/, 'grief'), "Gramm" (/gram/, 'gramm'), "Taten" (/t(h)atn/, 'actions'), or "Daten" (/datn/, 'data'). At the acoustic signal, the duration of the target vowels /a/ and /a:/ as well as the VOT of the word-initial alveolar stops /d/ and /t/ were determined. In addition, a master tape comprising the target words from patients and controls in randomized order was played to three listeners for perceptual evaluation. In accordance with a previous study, first, the cerebellar subjects presented with a reduced categorical separation of the VOT of voiced and unvoiced stop consonants. Second, vowel length distinctions were only compromised in case of the minimal pair "Gram"/"Gramm." In contrast to "Rate"/"Ratte", production of the former lexical items requires coordination of several orofacial structures. Disruption of vowel length contrasts would, thus, depend upon the complexity of the underlying articulatory pattern.     

The influence of syllable onset complexity and syllable frequency on speech motor control

Functional imaging studies have delineated a "minimal network for overt speech production", encompassing mesiofrontal structures (supplementary motor area, anterior cingulate gyrus), bilateral pre- and postcentral convolutions, extending rostrally into posterior parts of the inferior frontal gyrus (IFG) of the language-dominant hemisphere, left anterior insula as well as bilateral components of the basal ganglia, the cerebellum, and the thalamus. In order to further elucidate the specific contribution of these cerebral regions to speech motor planning, subjects were asked to read aloud visually presented bisyllabic pseudowords during functional magnetic resonance imaging (fMRI). The test stimuli systematically varied in onset complexity (CCV versus CV) and frequency of occurrence (high-frequency, HF versus low-frequency, LF) of the initial syllable. A cognitive subtraction approach revealed a significant main effect of syllable onset complexity (CCV versus CV) at the level of left posterior IFG, left anterior insula, and both cerebellar hemispheres. Conceivably, these areas closely cooperate in the sequencing of subsyllabic aspects of the sound structure of verbal utterances. A significant main effect of syllable frequency (LF versus HF), by contrast, did not emerge. However, calculation of the time series of hemodynamic activation within the various cerebral structures engaged in speech motor control revealed this factor to enhance functional connectivity between Broca's area and ipsilateral anterior insula.