Hemifacial spasm: an electrophysiological evidence of facial motorneurons hyperexcitability.

Twenty patients with primary hemifacial spasm and ten patients with Parkinson's disease were studied by means of paired stimuli blink reflex. The second stimuli were delivered at a varying time interval between 50-900 ms. The R2 response's absolute refractory periods were compared between patients and twenty one age-matched normal controls as well as between hemifacial spasm and Parkinson's disease. In normal subjects, the mean absolute refractory period was found to be 271.42 +/- 64.36 ms, in hemifacial spasm 160.00 +/- 50.62 ms and in Parkinson's disease 157.14 +/- 53.45 ms. The absolute refractory periods obtained from patients were significantly shorter than in normal controls (p < 0.05). However the values between patients with hemifacial spasm and Parkinson's disease were not (p > 0.05). This result strongly supports bilateral facial motoneurons hyperexcitability as the underlying mechanism of hemifacial spasm.

Carotid duplex scan; the first experience in Thailand.

To assess the clinical significance of carotid duplex scan in Thai patients, 53 healthy volunteers and 107 patients with either atherosclerotic heart/brain diseases, or associated with risk factors for atherosclerosis were examined by carotid duplex scan. The degrees of carotid stenosis were enumerated and classified as normal (0*), mild (< 40%), moderate (41 – 70%) and severe (> 70%) according to percentages of the thickest atheromatous plaque relative to the carotid diameter. There was 30 males and 23 females age ranged 33-63 years old in normal control group. The acute strike patients comprised of 37 males and 24 females with age range of 53-93 years. There were 23 patients of coronary thrombosis, 13 males and 10 females (age range 48-83 years). The asymptomatic patients with risk factors for atherosclerosis were 17 males and 10 females (between 43-63 years). There were 4 cases that had both coronary and cerebral thrombosis. The degree of carotid stenosis in the normal group was compared with the patients group. A P-value <0.05 was considered to be a significant difference. In normal volunteers, no atheromatous plaques were detected. There were significantly higher degrees of carotid stenosis in patients (p < 0.05) compared to normal subjects. Patients with cerebral thrombosis revealed the degree of 56% while in patients with the risk factors of ischemic heart-brain diseases the degree was 36% and the degree was 26% in angiographic proven coronary thrombosis. Carotid duplex scan is a new non-invasive ultrasonographic technique that can detect and monitor the progression of atherosclerosis.

Cortical blindness.

A 66-year-old Thai-Islam married male was admitted to the hospital for blindness of both eyes following vertigo and left sided dense hemiplegia. The hemiplegia was resolved within two hours, but he remained blind. Physical examination revealed a bilateral visual field defect with macular sparing. Brain CT scan and MRI disclosed bilateral occipital-infarction. EEg, visual evoked responses, and spectral analysis with topographic of recovery. After supportive treatment for seven days, his condition improved to the point that he could identify fingers at the central visual field.

The correlation of the short latency somatosensory evoked potentials and the strokes disability.

Median and tibial short latency somatosensory evoked potentials (SSEPs) were studied in 54 stroke patients, 27 males and 27 females. Thirty-two patients had cerebral infarction and 22 had cerebral hemorrhage. Median SSEPs abnormalities correlated with the Barthel score (p = 0.005) as well as tibial SSEPs (p = 0.01). Both median and tibial SSEPs were very sensitive (sensitivity = 79.41% and 85.71%) and high positive predictive value (77.14% and 75%) in the assessment of neurological disability. However, normal median and tibial SSEPs did not exclude severe neurological deficits (positive predictive value = 63.16%, 64.29% and sensitivity = 60%, 47.37%).

Muscular dystrophy with particular oculopharyngeal involvement.

The authors report the case of 33-year-old woman who presented with a 20 year history of external ophthalmoplegia with later involvement of pharyngeal and proximal muscles. Tensilon test excluded myasthenia gravis. Electromyography showed myopathy and muscle biopsy showed evidence of mitochondrial myopathy. Recent investigations revealed that the pathogenesis was probably due to abnormal genetic transmission in mitochondrial inner membrane respiratory chains. To the authors' knowledge, this is the first case reported in Thailand.