Isolated tongue tremor after removal of cerebellar pilocytic astrocytoma: Functional analysis with SPECT study

Hypertrophic Olivary Degeneration: Neurosurgical Perspective and Literature Review

BACKGROUND

Hypertrophic olivary degeneration (HOD) occurs because of posterior fossa or brainstem lesions that disrupt the dentato-rubro-olivary tract, well known as the Guillain-Mollaret triangle. Clinical and radiologic hallmarks of this condition are palatal myoclonus and T2 hyperintensity of the inferior olivary complex on magnetic resonance imaging (MRI), respectively. Because symptomatic HOD can complicate the recovery of patients with posterior fossa or brainstem lesions, the purpose of this study is to evaluate clinical and imaging findings of patients with HOD.

METHODS

Sixteen patients (8 female and 8 male) with a mean age of 40.7 years, (range, 5-83 years) years were included in this study based on clinical symptoms and MRI findings.

RESULTS

We reviewed the clinical and imaging findings in 16 cases of HOD at our institution. Seven patients (43.7%) had posterior fossa tumors, 6 patients (37.5%) had cavernoma, 2 patients (12.5%) sustained traumatic brain injury, and only 1 patient (6.2%) had cerebellar infarction. Posterior fossa surgery was performed in 13 (81.2%) of these patients. HOD was detected a mean of 7.2 months (range, 0.5-18 months) after surgery or primary neurologic insult. Unilateral HOD was observed in 10 patients (62.5%), while bilateral HOD was observed in only 6 patients (37.5%). Seven patients (43.7%) were asymptomatic for HOD, whereas 5 patients (31.2%) had symptoms attributable to HOD. Two patients died because of primary tumors, although mean follow-up after detection of HOD on MRI was 52.2 months (range, 1-120 months) in the remaining 14 patients. In these cases, no change in clinical symptoms or imaging findings was detected during follow-up.

CONCLUSIONS

In this series, posterior fossa tumors and cavernomas were the most common causes of HOD. Although most of the patients with HOD remained asymptomatic, HOD complicated the course of recovery in almost one quarter of the patients included in this study. Neurosurgeons should be aware of HOD, which has characteristic clinical and imaging findings. In addition, HOD can complicate the recovery of patients with disruption to the dentato-rubro-olivary tract.

[Case of an elderly woman with dementia showing episodic involuntary movement of the tongue]

We report a 93-year-old woman with dementia who developed generalized convulsion and involuntary movement of her tongue. She could independently walk and eat meals until 8 months ago, however she turned into bedridden. When she was admitted to our emergency room due to status epilepticus, her tongue intermittently moved from the midline to the left. She could not eat or speak during this episodic tongue movement. MR imaging study revealed brain atrophy in the bilateral mesial temporal lobe, consistent with senile dementia of Alzheimer type. Despite her tongue movements seemingly developing to the generalized convulsion, EEG study did not indicate epileptiform discharges corresponding to this movement. Although antiepileptic drug therapy was effective, we needed polytherapy to control this movement. Paroxysmal tongue movements were previously reported in cases of epilepsy, brain tumor, and stroke, observed bilaterally in most cases. This episodic tongue movement would be rare in terms of the clear laterality. The etiology of this movement was presumed as focal seizure, palatal tremor, dyskinesia or others, but was undetermined. Episodic movements involving tongue decrease the quality of daily life especially in the elderly. Therefore, we should pay more attention to it and try to treat it earlier.

Left leg apraxia after anterior cerebral artery territory infarction: functional analysis using single-photon emission computed tomography

Left hand apraxia is known as a unique symptom of callosal apraxia, but lower limb symptoms are rarely mentioned. We report a patient who experienced left ideomotor apraxia affecting both the upper and lower limbs after a stroke in the territory of the right anterior cerebral artery. His spontaneous gait was normal, but he was unable to move his left leg intentionally either by verbal command or by imitation. His leg symptoms gradually improved over time. We evaluated the change in cerebral blood flow in this patient using single-photon emission computed tomography. The results showed an increase in blood flow in the posterior corpus callosum; therefore, we suggested that the callosal pathway might contribute to left leg as well as left hand volitional movement.

Hypertrophic olivary degeneration in children: four new cases and a review of the literature with an emphasis on the MRI findings

Injury to the dentato-rubro-olivary pathway causes hypertrophy and enlargement of the inferior olivary nuclei, which is called hypertrophic olivary degeneration (HOD). To date, adult cases of HOD have usually been reported, and there are only a few individual paediatric cases with limited radiological emphasis in the literature. We present the clinical and MRI findings of four new paediatric cases with HOD. Three of the patients had a posterior fossa surgery, and one did not have an identifiable cause.

Tongue tremor: a rare initial presentation of essential tremor

Tongue tremor is commonly associated with essential tremor, but rarely presents as an initial finding. Essential tremor is the most common movement disorder and is characterised by 4-12 Hz postural and kinetic tremor, but there is no universally accepted diagnostic criterion. It commonly affects the arms, and to a lesser extent, other regions of the body, and signs and symptoms tend to worsen during emotional or physiological stress. We describe a rare isolated presentation of tongue tremor as a part of essential tremor, its management, and the diagnostic dilemma. To our knowledge isolated tongue tremor as a presentation of essential tremor has not previously been described in maxillofacial publications.