Chul-Hyoung Lyoo

“Off” gait freezing and temporal discrimination threshold in patients with Parkinson disease

Objective: To investigate the relationship between temporal discrimination threshold (TDT) and “off” period gait freezing (OGF) in patients with fluctuating Parkinson disease (PD). Methods: TDT values were measured at the dorsum of the toes in 11 control subjects and 22 patients with PD with a wearing-off phenomenon (16 patients with OGF and 6 patients without OGF). Results: During the l-dopa “off” period, TDT values increased abnormally in both patient groups but were significantly higher in patients with OGF than in those without OGF. A positive correlation was found between the severity of OGF and TDT values measured by different point stimulation. In patients with OGF, a single dose of l-dopa treatment normalized TDT values and ameliorated OGF. Conclusions: Dopa-responsive abnormal discriminative sensory processing may be a possible cause of “off” period gait freezing observed in patients with fluctuating Parkinson disease.

Effects of disease duration on the clinical features and brain glucose metabolism in patients with mixed type multiple system atrophy

To study the effect of disease duration on the clinical, neuropsychological and [(18)F]-deoxyglucose (FDG) PET findings in patients with mixed type multiple system atrophy (MSA), this study included 16 controls and 37 mixed-type MSA patients with a shorter than a 3-year history of cerebellar or parkinsonian symptoms. We classified the patients into three groups according to the duration of parkinsonian or cerebellar symptoms (Group I = <or=1 year; II = 13-24 months; III = 25-36 months). We performed UPDRS, international cooperative ataxia rating scale (ICARS), and a neuropsychological test battery. We compared the FDG PET findings of each group of patients with controls. Group I patients frequently had memory and frontal executive dysfunction. They showed hypometabolism in the frontal cortex, anterior cerebellar hemisphere and vermis. They had parkinsonian motor deficits, but no basal ganglia hypometabolism. Group II and III patients frequently had multiple domain cognitive impairments, and showed hypometabolism in the frontal and parieto-temporal cortices. Hypometabolism of the bilateral caudate and the left posterolateral putamen was observed in Group II, and whole striatum in Group III. In summary, the cortical hypometabolism begins in the frontal cortex and spreads to the parieto-temporal cortex in MSA. This spreading pattern coincides with the progressive cognitive decline. Early caudate hypometabolism may also contribute to the cognitive impairment. Parkinsonian motor deficits precede putaminal hypometabolism that begins in its posterolateral part. Cerebellar hypometabolism occurs early in the clinical courses and seems to be a relevant metabolic descriptor of cerebellar deficits.

Oculogyric crisis as an initial manifestation of Wilson’s disease

Wilson’s disease is an autosomal-recessive inherited disease caused by a defect on chromosome 13 encoding copper transporting P-type adenosine triphosphatase. Although patients with Wilson’s disease have a fundamental defect in the hepatobiliary system, they have various combinations of neurologic, psychiatric, and musculoskeletal manifestations. In the early 20th century, the most common cause of oculogyric crisis (OGC) was postencephalitic parkinsonism.1 Now it is most frequently reported as a complication of short- or long-term treatment with neuroleptics or other drugs.2 Tonic upward deviation of the eyes has been observed in patients with Chediak-Higashi’s, Rett’s, and Tourette’s syndromes. Several patients with OGC associated with focal lesions in the basal ganglia or thalamus have also been reported.3,4 We report a young girl who developed paroxysmal forceful upward deviation of eyes as an initial manifestation of Wilson’s disease. An 11-year-old girl, otherwise healthy, experienced paroxysmal attacks of retrocollis and …

Corticospinal disinhibition in paroxysmal kinesigenic dyskinesia

OBJECTIVE To investigate the underlying mechanism responsible for paroxysmal kinesigenic dyskinesia (PKD). METHODS We performed a transcranial magnetic stimulation (TMS) study in 12 drug-naïve patients with PKD and 10 healthy volunteers. TMS parameters included resting motor threshold, recruitment curve of motor evoked potential amplitudes, short intracortical inhibition and facilitation, long intracortical inhibition (LICI), and silent period. We also measured compound muscle action potential. RESULTS LICI, representing GABA-mediated inhibition, was significantly reduced in the patients (P = 0.033), while results for all other TMS parameters tested were comparable between the two groups. CONCLUSIONS AND SIGNIFICANCE These results suggest that a specific type of corticospinal inhibitory mechanism is impaired in patients with PKD.