Predictive Value of Multi-Sensory Evoked Potentials on Motor Development of Neonates

OBJECTIVE: This study was performed to investigate the prognostic value of multi-sensory evoked potentials (MSEPs) in neonatal period for the early diagnosis of delayed motor development, especially cerebral palsy. METHOD: The MSEPs studies composed of auditory brainstem evoked potentials (AEPs), visual evoked potentials (VEPs) and somatosensory evoked potentials were taken on 237 neonates, 136 boys and 101 girls, using Viking IV machine. Follow up MSEPs were repeated in every 4 or more weeks for those who showed abnormal responses in any of the MSEPs. Each neonate was also evaluated for motor development as an outpatient or by telephone interview. RESULTS: Among 237 neonates, 6.4% showed delayed development, and 4.6% were cerebral palsy: 3.8%, spastic type; 0.8%, athetoid type, and the others revealed normal motor development. AEP was useful method to predict motor development when this was done at 39.7 0.4 weeks of postmenstrual age (PMA). VEPs failed to show the validity, but there was the typical waveform change in accordance with increase of the postmenstrual age. Median nerve SEPs were valuable for prediction of motor development which were taken at PMA 40.7 0.6 weeks. After 45.3 1.5 weeks of PMA, median nerve SEPs did not reflect motor development outcome significantly. However, posterior tibial SEPs significantly reflect motor outcome regardless of the time of examination. CONCLUSION: Median and posterior tibial SEPs done before 40weeks of PMA are useful tool to predict motor development outcome. When any of these tests showed abnormal findings, follow up study is recommended and posterior tibial SEP study is thought to be the most useful for its predictability. It is necessary to correlate the AEPs and VEPs with hearing and vision whenever abnormal findings are found.

Visual Evoked Potentials in Premature Infants

Visual evoked potentials(VEPs) are the cerebral electrical activities recorded from the occipital scalp following a flash or pattern stimulation and can detect the lesions of sensory visual pathways. Although the VEPs change with the maturation of CNS in children, a few studies have documented the maturational changes in premature infants. Using the light- emitting diode goggles, VEPs were studied in 131 neurologically intact infants of 28~41 weeks gestational age or 34~59 weeks postmenstrual age. The VEPs were analysed by three waveforms; normal, abnormal, and flat, and four patterns; N300, P200-N300, P100-N155-P200-N300, and P100 pattern. Normal waveforms were 63 of 131 VEPs(48.1%). Of the normal waveforms, N300 patterns were 38.1%, P200-N300 36.5%, P100-N155-P200-N300 19.0%, and P100 6.4%. Each pattern correlated with the postmenstrual age. These findings support the hypothesis of VEP pattern changes according to the maturation of the visual system with age.

Somatosensory Evoked Potentials in Neonates

The purpose of this study was to investigate the maturation characteristics of neonates. Ninety three neonates underwent a somatosensory evoked potentials(SEPs) testing. Twenty four point seven percent of them were neonates at risks including the neonatal asphyxia, low birth weight under 1500 g, or a suspicious CNS abnormality. Seventy five point three percent of neonates showed normal median SEPs, and 24.7% of them showed abnormal or a flat response. The mean latency of the first cortical component(N1) was 25.3+/-5.4 msec, duration 16.3+/-5.5 msec and amplitude 1.00+/-1.27 V. Thirty one point two percent of neonates showed normal posterior tibial SEPs, and 68.8% showed abnormal or a flat response. The mean latency of the first cortical component(P1) was 44.9+/-5.6 msec, duration 17.5+/-3.9 msec and amplitude 0.47+/-0.38 V. This result suggests that the maturation of rostal nervous system develops earlier than the caudal system. Linear decrease of the cortical latency with post-menstrual age reflects maturation of the central pathway and not merely maturation of the peripheral nerves. But our study showed much less frequency of recordings of the tibial nerve SEPs than the median nerve responses, which suggested that the maturation of spinal cord and lower-limb nerves would be slow, in addition to that the length of pathway was increasing. This result suggests that the maturation of the proximal shorter nervous pathway develops earlier than the distal longer pathway.

Clinical Features of Sequelae in Poliomyelitis Patients

The Postpoliomyelitis syndrome (PPS) is characterized by new neuromuscular symptoms such as muscle weakness, joint pain, fatigue, and occasional new neuromuscular impairments. Although the development of PPS shows individual differences, it usually occurs many years after the recovery from an acute paralytic poliomyelitis. The purpose of this study was to investigate the incidence and the clinical features of PPS. The subjects were 33 patients(26 males and 7 females) who had partial recoveries of motor function, ten or more years of functional stabilities, and residual muscle atrophies. The mean age was 36.8?7.7 years with the range of 23 - 59 years. The average onset age of acute poliomyelitis was 2.3 - 1.5 years. The questionnaires asking their current physical conditions and three major categories of PPS symptoms, weakness, fatigue, and pain were used. As the sequelae of poliomyelitis, 66.7% of the subjects showed scoliosis and 39.4% had claw toes. Thirty six percents of the subjects were using orthoses including wheelchair, KAFO, and crutches. According to the questionnaire study, 72.5% of subjects had at least one of the three major symptoms. And 36.4% of them reported all of three categories of PPS symptoms. The onset age of the new neuromuscular symptoms was 34.2?8.3 years which was about 32 years after the original acute poliomyelitis. Further researches to investigate the importance and the impacts of proper managements and to develop educational plans for the PPS including exercise programs, cardiopulmonary and energy-conservation trainings are recommended.