Myokymia is a clinical phenomenon characterized by undulating, vermicular, rippling and wavelike movements spreading across the muscle surface. Facial myokymia is an unusual complication of brainstem hemorrhage. It tends to occur in brainstem tumor or multiple sclerosis. We report a 51-year-old man with continuous facial and neck myokymia after brainstem hemorrhage, who revealed focal myokymic discharges in face, neck and pharyngolaryngeal muscles innervated by cranial nerve V, VII, X, and XI. After injection of 20∼80 units of Botulinum toxin type A (Dysport^Ⱂ) to the left orbicularis oris, mentalis, mylohyoid and posterior belly of digastric muscles, amplitude of continuous myokymic discharges was markedly reduced. We recommend Botulinum toxin injection as a very effective therapeutic method in managing focal movement disorders. (J Korean Acad Rehab Med 2002; 26: 358-362)

Objective: To determine optimal follow-up time of BAEP for the infants with abnormal BAEP at the initial screening test.

Method: Control group consisted of 85 infants with normal BAEP and experimental group consisted of 41 infants with abnormal BAEP at the first examination but normalized on regular follow-up examinations. Gestational age (correctional age), intrauterine period, birth weight, delivery method, presence of perinatal asphyxia, Apgar score after 1 minute, the highest serum bilirubin level, and the results of cranial ultrasonography were recorded. The above parameters, peak and interpeak latencies of BAEP were compared between both groups.

Results: Lower correctional age at the first BAEP, shorter intrauterine period, and lower birth weight were noted in experimental group (p＜0.001). The average correctional age when BAEP had normalized in experimental group was 45.0⁑5.8 weeks, which was much later than 40.2 ± 2.8 weeks in control group (p＜0.001). 90.2% of infants among experimental group revealed normalized BAEP within 48 weeks, and 95.1% within 51 weeks according to correctional age, or within 12 weeks after initial examination.

Conclusion: We recommend that BAEP should be rechecked after 48 weeks by correctional age for the high risk infants who were abnormal with initial screening BAEP.

Objective: To investigate the change of peak latency, interpeak latency and amplitude of auditory brainstem evoked potentials (AEPs) in normal preterm infants in accordance with the age, and to find out the correlation between reproducibility of AEPs and high risk of premature infants.

Method: AEP studies were performed on 266 premature infants (male 143, female 123) within a month of the birth. Acquired potentials were grouped by the reproducibility of waveforms, and latency, interpeak latency and amplitude were measured in each group of potentials to interpret age appropriate changes of AEPs.

Results: 1) Peak latency of peak I, III and V were shortened in accordance with the age, especially latency of peak V was significantly decreased from 7.42 msec to 6.84 msec. 2) There was no significant change in interpeak latency or amplitude of AEPs according to the postmenstrual age. 3) Reproducibility of AEPs was worse in premature infants with history of asphyxia.

Conclusion: Considering the results, the latency of peak V can be used as one of the useful parameter to investigate and follow up the premature infants. Significant negative correlation between low grade reproducibility and history of neonatal asphyxia was found.

Objective: To observe the prognostic value of brainstem auditory evoked potentials (BAEP) for prediction of cerebral palsy (CP) in the high-risk neonates.

Method: Eighty-one high-risk neonates were subjected to take the history of illness, neurological examination, developmental assessment, BAEP study within one month after birth. They had been checked for detection and management of the CP in period of 12 to 56 months after birth. Associating factors were observed about their gestational age at birth, 1-minute Apgar score, history of asphyxia and/or intubation, and hyperbilirubinemia and/or exchange transfusion.

Results: Abnormal BAEP findings were seen in 38 of 81 (46.9%) high-risk neonates and 6 of 81 (7.4%) were diagnosed as a CP. Five of 6 CPs and 42 of 75 non-CPs had been abnormal in BAEP study. Neonatal BAEP study showed 83.3% sensitivity, 44% specificity, 98.4% false positive and 2.9% false negative in predicting CP. Asphyxia showed high correlation with abnormality of BAEP and CP (p＜0.01). Gestational age, low birth weight, toxemia, germinal matrix hemorrhage (GMH) grade II and intubation were correlated with CP (p＜0.05) but not with the abnormality of BAEP.

Conclusion: It is suggested that BAEP study of high-risk neonate is useful in prediction of CP because of low false negative and high sensitivity.

Objective: The purpose of this study was to determine the usefulness of brainstem evoked potential (BAEP) in the diagnosis of cerebellopontine angle (CPA) tumors.

Method: Sixteen subjects in which BAEP study was compatible with CPA tumors were retrospectively reviewed and analyzed the results of BAEP, findings of CT and MRI, and clinical signs.

Result: Thirteen subjects were reviewed and three were lost in follow-up. 1) CPA tumors were confirmed with CT/MRI in 10 subjects and the other 3 patients had other lesions which could be differentiated from CPA tumors clinically. The positive hit rate of BAEP was 76.9% in 13 patients whose findings were compatible with CPA lesion. 2) Of 10 patients with CPA tumor, the tumors were bilateral in 4 patients and unilateral in 6 patients, and the diagnosis of the tumors were vestibular schwannoma in 9 patients and meningioma in 1 patient. 3) The major symptoms of the patients with CPA tumors were hearing loss, tinnitus, dizziness, facial nerve palsy, headache, cerebellar dysfunction, nystagmus, and vertigo. 4) The most common abnormal findings of BAEP in the patients with CPA tumors were increase in the interpeak latency I-III and I-V on the affected side and interpeak latency III-V on the unaffected side.

Conclusion: The BAEP considering clinical correlation is a useful study as a screening test in the diagnosis of CPA tumors because of its high positive hit rate and cost-effectiveness compared with CT/MRI.

Objective: The purpose of the study is to draw the three-dimensional reconstructions of nuclei and tracts of the auditory pathway structures of drainstem.

Method: The drawings of 1 mm sections of the brainstem were scanned with a computer scanner into AUTOCAD program. All lines of structures except for the auditory pathway structures and outlines were removed. Each layer was plotted to a x, y, and z coordinated plotting reference to the corresponding points on the mid-sagittal plane and reconstructed to a three-dimensional drawing. Center point of the auditory pathway structures of all cross section layers were connected with a line in succession and that was thought to be a imaginary pathway of auditory pathway through the brainstem.

Results: This auditory pathway has several turning points, at the cochlear nucleus, superior olivary nucleus, and inferior colliculus which correspond with known generation sources of the peak of brainstem evoked potentials.

Conclusion: This study presents a method for the conversion of the two-dimensional transverse sections into a three-dimensional format, to allow the visualization of the auditory pathway structures from multiple directions.

Objective: Maturation of the acoustic and visual pathways in brainstem can be reflected by the brainstem auditory evoked potential(BAEP) and visual evoked potential(VEP) response studies. The purpose of this study was to evaluate the high-risk infants by the BAEP and VEP studies as a screening test for Their brainstem maturities.

Method: The BAEP and VEP studies were used as a screening test in 142 high-risk infants with 31 to 42 weeks of conceptional age. Further follow-up data were obtained within 1 year in the same infants who showed the abnormal findings in BAEP and VEP at an initial screening test.

Results: On an initial BAEP and VEP study, the proportion of the abnormal findings was significantly higher among infants with below 36weeks(53.8%, 28.2%) of conceptional age than above 36 weeks(27.2%, 3.9%). At the follow-up study, 3 of 21 infants with no responses in BAEP and 1 of 6 infants with no responses in VEP on an initial test showed the persistent abnormal findings. However, normal configurations of BAEP and VEP were observed in infants with prolonged latencies or with distorted waveforms of BAEP and VEP at the first examination.

Conclusions: These results suggest that the BAEP and VEP studies on the useful screening tests in infants above 36weeks of conceptional age. Because of the risk of persistent abnormal results, infants with no responses on an initial screening test need a follow-up study.

Familial hypophosphatemic ricket (Vitamin D-resistant ricket), first described by Albright in 1937, has been known to be transmitted as an X-linked dominant trait in most families. Children with this disease would show growth retardation with characteristic clinical features such as congenital alopecia, genu varum or genu valgum, coxa vara and waddling gait. Although the physical features associated with this disease have been documented frequently, the potential involvement of auditory pathway due to abnormal bone formation in skull has not been explored frequently.

We report a twenty six-month-old female child with familial hypophosphatemic ricket who presented abnormal findings of brainstem auditory evoked potential study. The impaired hearing function should be alerted as one of possible accompanying disabilities of the disease.