Increased glucose metabolism in the medulla of patients with palatal myoclonus

Hypertrophic degeneration of the inferior olivary nuclei is the pathologic substrate for palatal myoclonus, but the physiologic correlate of this finding is uncertain. Using the 2-[18F]fluoro-2-deoxy-D-glucose and PET method, we determined the local cerebral metabolic rate of glucose utilization in seven patients with palatal myoclonus (following stroke or infection, or idiopathic), one patient with oculopalatal myoclonus (following a stroke affecting the brainstem), and nine normal subjects. The metabolism of glucose in the medulla of the patients with palatal myoclonus was significantly greater than that of the normal subjects. This may well have been due to increased metabolism of the inferior olivary nuclei. Glucose metabolism in the medulla of the patient with oculopalatal myoclonus was normal. These findings suggest that the inferior olivary nuclei, or a region of the brainstem encompassing the inferior olivary nuclei, are hypermetabolic in palatal myoclonus and may be the generators of the involuntary movements in palatal myoclonus.     

Palatal "myoclonus" and inferior olive hypertrophy with one-sided cerebellar lesion. Clinico-pathological report of one patient

A case of palatal myoclonus and inferior olive hypertrophy is reported. Lesions located other than in the medulla were cerebellar infarction, lymphomatous infiltrates and, supratentorially, progressive multifocal leukoencephalopathy. It is suggested that double innervation of the olives from either side dentate nucleus may be why in the case reported here and in several cases in the literature, one-sided supra-olivary lesions can produce bilateral hypertrophy. As with palatal "myoclonus" and olivary hypertrophy, it is proposed that if the characteristic rhythmical movements occur, lesions besides those along the dentate-olivary pathway and the olivary hypertrophy itself have to be present.     

Palatal tremor as a manifestation of epilepsia partialis continua caused by acute precentral gyral infarction

We describe a patient with palatal tremor (PT) as a manifestation of focal seizure caused by acute cortical infarction. Brain MRI showed acute infarction in the left precentral gyrus without evidence of brainstem lesions or hypertrophy of the inferior olivary nucleus. We discuss the differences between our patient and previous reports of symptomatic PT and the mechanisms involved in the development of PT associated with cortical lesions.     

Natural course of combined limb and palatal tremor caused by cerebellar-brain stem infarction.

After infarction of the left superior cerebellar peduncle and dentate nucleus, a patient developed tremor of the left upper limb beginning on the twelfth day followed by palatal tremor appearing 10 months after infarction. Surface electromyogram revealed a difference in the frequency of the tremor in the upper limb and soft palate. When the palatal tremor appeared, brain magnetic resonance T2-weighted images revealed high signal intensity of the contralateral, right inferior olivary nucleus. Subsequently, when the amplitude of palatal tremor became less severe, the high olivary signal intensity subsided whereas the hypertrophy of the nucleus remained. This patient provides useful information on the pathogenesis of skeletal and palatal tremor with brain stem or cerebellar lesions based on the differences in the onset and frequency of tremors and morphologic changes in the inferior olive.     

脑桥出血后继发肥大性下橄榄核变性的临床及影像学特点

目的探讨脑桥出血后继发肥大性下橄榄核变性症(hypertrophic inferior olivary degenerationsyndrome,HOD)的临床及影像学特点。方法对2009年1月至2011年6月在我院确诊的脑桥出血的65例,其中63例患者进行为期1年的随访,并对随访过程中发现有继发性下橄榄核变性症的9例患者的临床资料进行分析。结果HOD发生影像学改变时仅有3例患者有临床症状,主要表现为眼震、软腭阵挛、躯干粗大震颤。脑桥出血均发生在被盖区。头颅MRI下橄榄核信号改变距离出血时间平均为4.05个月。出血病灶9例中有8例存在含铁血红素沉着。肥大的橄榄核直径多数在0.7～0.8 cm左右,下橄榄核信号改变6例为等T1WI,长T2WI改变,3例为长T1WI长T2WI改变,其中2例长T1WI患者出现典型临床症状。7例Flair显像为高信号,1例低信号,1例为等信号。治疗上,1例患者先后予森福罗、氯硝西泮、心得安、氟哌啶醇、美多巴等治疗,其中氯硝西泮及心得安有效。结论HOD多发生在脑桥被盖部出血1个月后,头颅MRI特征为下橄榄核区的圆形的T2WI长信号改变;予心得安及氯硝西泮可能有效。     

Progressive supranuclear palsy with palatal myoclonus

We present a case of progressive supranuclear palsy (PSP) with palatal myoclonus occurred in a 64-year-old man. The nucleus olivaris of the medulla oblongata showed high signal intensity on T2-weighted MR images, indicating brainstem tegmental atrophy, which were confirmed as hypertrophy of the nucleus inferior olivaris at autopsy. The characteristic neuropathological findings were marked grumose degeneration of the dentate nucleus, degeneration and gliosis of the superior cerebellar peduncle, and hypertrophy of the bilateral olivary nuclei. As far as we know, although a few cases of PSP with olivary hypertrophy have been described, only one case has presented with palatal myoclonus. Received: 11 September 1996 / Revised: 17 December 1996, 31 January 1997 / Accepted: 3 February 1997     

Transneuronal degeneration of the inferior olivary nuclei in system atrophy

Summary Hypertrophy of the inferior olivary nuclei was observed in a patient who had progressive ataxia during life but no palatal myoclonus. A definite family history could not be established. Central nervous system lesions included sweeping loss of Purkinje cells, fiber depletion of the cerebellar white matter, neuronal loss and gliosis of the dentate nuclei, necrobiosis of neurons of the substantia nigra, and dorsal column degeneration. Olivary changes included nerve cell loss, enlargement of the remaining neuronal cell bodies in the anterior folds of the inferior olivary nuclei with formation of elaborate dendritic expansion (glomeruloid structures) and neuronal vacuolation, and proliferation of astrocytes. In contrast, the dorsal folds of the inferior olivary nuclei and medial and dorsal accessory olives revealed retrograde atrophy of neurons.Neither palatal myoclonus nor olivary hypertrophy are common accompaniments of hereditary and nonhereditary system atrophies of cerebellum and brainstem.     

Palatal myoclonus secondary to vertebral artery compression of the inferior olive.

A 47-year-old male with a 5-year history of palatal myoclonus was found on magnetic resonance imaging (MRI) examination to have an ectatic dominant left vertebral artery that compressed the left inferior olive. Microvascular decompression effectively eliminated his symptoms. This case and a similar case presented here with an ectatic vertebral-basilar system illustrate the value of standard MRI in conjunction with magnetic resonance angiography (MRA) in evaluating palatal myoclonus, and they suggest a potential role for decompressive surgery when persistent, highly symptomatic inferior olivary ischemia or compression occurs.     

Palatal myoclonus associated with extremity tremor

Summary Palatal myoclonus associated with extremity movements such as myoclonus or tremor is uncommon and reports are rare. Five patients with palatal myoclonus and a rest tremor are presented. In four patients, a slow rest tremor (3 Hz or less) was present. The tremor persisted on sustained posture and finger-to-nose maneuvers and was usually not synchronous with the palatal movements. It was not associated with clinical manifestations of Parkinson's disease and occurred in conjunction with brain-stem infarction in three patients.     

An autopsy case of progressive supranuclear palsy with olivary hypertrophy]

Clinical and pathologic findings of an autopsy case of progressive supranuclear palsy (PSP) with a 7 year clinical course are described. The patient exhibited clinical findings of typical PSP, cerebellar signs and rhythmical myoclonus that was about 2 Hz and synchronous in the eyes, palate, and pharynx, which is so called palatal myoclonus. Pathological findings compatible with those in PSP i.e. loss of nerve cells, neurofibrillary tangles (NFT), and gliosis were found in the globus pallidum, thalamus, subthalamic nucleus, substantia nigra, locus coeruleus, nucleus of Raphe, reticular formation, dentate nucleus, and inferior olives. Nerve cells in the nucleus basalis were preserved. Distinctive findings included marked degeneration of the dentate nucleus, prominent hypertrophy of the inferior olives, and atrophy and subcortical gliosis of the frontal lobe. Hypertrophy of the inferior olives and palatal myoclonus represent an unusual PSP. It is presumed hypoxic injury unmasked the palatal myoclonus in this setting of dentate nucleus and inferior olivary complex degeneration.     

Olivary hypertrophy in a case with palatal myoclonus: light- and electron-microscopic study

This is a report on the ultrastructural finding of the olivary hypertrophy in a case with palatal myoclonus. By light microscopy two types of neuronal changes were observed in the inferior olivary nucleus, i.e. the central chromatolysis and cytoplasmic vacuolation. Both types were also recognized by electron microscopy and the cytoplasmic vascuolation was identified as the vesiculated endoplasmic reticulum. In the reactive astrocytes, mitochondria were strikingly proliferated.     

Olivary Hypertrophy in a Case with Palatal Myoclonus:Light- and Electron-microscopic Study

Abstract: This is a report on the ultrastructural finding of the olivary hypertrophy in a case with palatal myoclonus. By light microscopy two types of neuronal changes were observed in the inferior olivary nucleus, i.e. the central chromatolysis and cytoplasmic vacuolation. Both types were also recognized by electron microscopy and the cytoplasmic vascuolation was identified as the vesiculated endoplasmic reticulum. In the reactive astrocytes, mitochondria were strikingly proliferated.     

Olivary hypertrophy without palatal myoclonus associated with a metastatic lesion to the pontine tegmentum.

A 46-year-old man had metastasis to the central tegmental tract of the pons with ipsilateral olivary hypertrophy. Although the phenomenon of palatal myochlonus has been repeatedly correlated with the finding of olivary hypertrophy, no palatal myoclonus was noted on repeated examinations. The clinical pathologic correlates and literature of similar cases are reviewed.     

Olivary hypertrophy: histochemical demonstration of hydrolytic enzymes

Of four patients with palatal myoclonus, three had infarcts resulting from atherosclerosis, and one had cerebral emboli from a left atrial myxoma. Three specimens showed lesions in the brainstem and bilateral hypertrophy of the inferior olivary nuclei; the fourth revealed unilateral olivary changes caused by an infarct in the contralateral dentate nucleus. After incubation for acetylcholinesterase, neuropilar and capillary wall staining were absent or much reduced, but there was increased denisty of reaction product in the neuronal cell bodies and in numerous tortuous dendrites. Methods for acid phosphatase showed strong activity in the dendrites and glomeruloid structures of the diseased olives. Reactions for nonspecific esterase indicated dendritic expansion and reduced staining density in nerve cell bodies, but augmented glial reactivity.     

Tremor of the mouth floor and anti-glutamic acid decarboxylase autoantibodies

Involuntary movements of the mouth can present as palatal tremor, which is frequently associated with hypertrophy of the inferior olivary nucleus and can be accompanied by contraction of other muscles of the head. We report the case of a 39-year-old man with autoimmune thyroiditis and diabetes who complained of involuntary rhythmic tremor involving the muscles of the floor of the mouth, which interfered with breathing and swallowing. Cerebrospinal fluid (CSF) examination showed the presence of oligoclonal bands and screening for anti-neuronal antibodies revealed high titres of anti-glutamic acid decarboxylase autoantibodies (GAD-Ab). Tremor responded to treatment with benzodiazepines. The correlation between the tremor and antibody positivity is unclear although an alteration of the gabaergic system mediated by the antibodies may be hypothesised on the basis of an inflammatory CSF profile.     

Myorhythmia emerging on day 15 in a case of an infarction in the midbrain-pontine tegmentum]

A 72-year-old woman was admitted to our hospital because of dysarthria, dysstasia, and diplopia. Examination demonstrated wall-eyed bilateral internuclear ophthalmoplegia (WEBINO) syndrome, dysarthria, truncal ataxia, and dysmetria of the four limbs. Cranial MR images demonstrated an acute infarct in the paramedian, lower midbrain-pontine tegmentum. Peduncular hallucinosis was observed during the first several days of hospitalization. Myorhythmia (skeletal myoclonus) appeared as early as day 15 and has persisted to date, with a frequency of approximately 1.5 Hz on the head and chin, and 3.5 Hz on the left upper extremity. Cranial MR images 5 months after onset demonstrated bilateral inferior olivary hypertrophy, while palatal tremor appeared later. Only a limited number of case reports are available in which myorhythmia emerged as early as in our case after the onset of a brain infarct.     

Bulbar myoclonus without palatal myoclonus. A hypothesis on pathophysiology

A 40-year-old woman with myoclonic contractions bilaterally in the infrahyoid neck muscles, especially in the left cricothyroid muscle, was presented and successfully treated with botulinum toxin injections. The patient had a wide, aberrant vessel curving into the left dorsolateral reticular formation of the medulla oblongata. Based on our observations, we propose that symptomatic bulbar and palatal myoclonus is caused by pathology in the dorsolateral reticular formation, and not by inferior olivary dysfunction as is currently thought.     

Inferior olivary hypertrophy is uncommon in progressive supranuclear palsy

Inferior olivary hypertrophy (IOH) is an uncommon disorder attributed to transsynaptic degeneration and characterized clinically by palatal myoclonus and histopathologically by swollen, fenestrated neurons and bizarre astrocytic gliosis. IOH is usually associated with the interruption of the dentato-olivary tract, most often from cerebrovascular lesions in the dentate nucleus or red nucleus. In progressive supranuclear palsy (PSP), the dentato-olivary tract is consistently affected, and there are reports suggesting that IOH may be relatively common in PSP. To address this issue, the frequency of IOH was investigated in 264 PSP brains. To determine if there was a relationship between IOH and neurofibrillary degeneration in the dentato-olivary pathway, the severity of neurofibrillary degeneration was assessed in the inferior olivary nucleus, cerebellar dentate nucleus and red nucleus in PSP cases with and without IOH. IOH was uncommon in PSP, being found in only 4 of 264 (1.5%) brains, which was not significantly different from the frequency in non-PSP controls (8 of 862; 0.9%). In all non-PSP cases IOH was associated with cerebrovascular lesions, but not in any of the PSP cases with IOH. The severity of neurofibrillary degeneration in the inferior olivary nucleus was significantly greater in PSP cases with IOH than in PSP cases without IOH, whereas there were no significant differences in the cerebellar dentate nucleus and red nucleus. These findings suggest that direct neurofibrillary degeneration in the inferior olivary nucleus may be related to IOH in PSP rather than transsynaptic degeneration.     

Palatal Myoclonus (syn. Palatal Tremor)

Symptomatic palatal tremor is caused by a lesion in the triangle of Guillain and Mollaret and is associated with hypertrophic olivary degeneration that has multiple causes. Essential palatal tremor has no currently demonstrable cause and no accompanying physical or radiological signs. But it is probable that an organic genesis will become apparent. I suggest that some examples of palatal tremor may depend on an 'upper motor neurone type', i.e. supranuclear, lesion in the striatum or rostral brainstem releasing medullary activation with denervation hypersensitivity of olivary neurones.     

Early detection of post-traumatic olivary hypertrophy by MRI

Two patients are described, in whom MRI detected unilateral signal abnormalities in the region of the inferior olivary nuclei, suggesting an early stage of olivary hypertrophy. MRI was performed 4 and 7 weeks respectively after traumatic brain-stem injury. Palatal myoclonus was concomitantly observed in one patient, while the other showed no evidence of segmental myoclonus at the time of examination. The authors conclude that MRI is highly sensitive in the detection of olivary hypertrophy and of traumatic lesions of the dentatorubro-olivary pathway.