Effect of Refractive Error on the P100 Latency of Visual Evoked Response

OBJECTIVE: Absolute or relative increase in the latency of the major surface positive component is almost invariably found in patients with demyelination optic neuropathy. Using the pattern- reversal method, our study illustrates the significant changes in the latency of the P100 component when refractive errors are introduced to defocus in normal person. METHOD: Four women and ten men aged 20 to 27 years were selected after a thorough ophthalmological assessment. Visual acuity (VA) was 6/6 or better in all subject and none had dyschromatopsia or significant astigmatism. Refractive errors were created by the combined standard lenses. RESULTS: The mean value of P100 latency were as follows: 93.74 +/- 3.30 msec, naked eyes; 98.14 +/- 7.37 msec, the +2/+x 90 lens; 96.50 +/- 3.76 msec, the +1/ +1 x90 lens; 94.55 +/- 4.20 msec, the -1/ -1x90; 96.29 +/- 2.88 msec, the -2/ -2 x90 lens. The P100 latencies showed singnificant standard lens except with -1/ -1 x90 lens. The P100 latency was prolonged according to the progression of refractive error. CONCLUSION: Because a relative or absolute prolongation of P100 latency is often found in cases of suspected multiple sclerosis, and because of their similarity to the findings of our study, we would emphasize that refractive errors should be reduced or eliminated to minimize the false-positive results.

Follow-up Magnetic Resonance Imaging Study of Patients with Herniated Lumbar Intervertebral Disc Who Were Treated Conservatively

OBJECTIVE: To clarify the relationship between the morphologic changes of disc herniation and the clinical course of conservatively treated herniated lumbar disc patients. METHOD: Follow-up MRIs and clinical assessments by the Visual Analogue Scale and Japanese Orthopaedic Association(JOA) Score were performed in 20 patients at a mean interval of 11.3 month. RESULTS: An average reduction ratio of herniation on the sagittal and axial images, were 21.4% and 20.8% respectively. The clinical features improved significantly and the degree of clinical improvement correlated with the reduction ratio of herniation, althougy 4 patients improved symptomatically despite increased or unchanged degree of herniation. Ten patients with extruded discs showed a higher reduction ratio of heniation with better clinical outcome than those with protruded discs. CONCLUSION: The morphologic change verified on MRI of conservatively treated patients with a lumbar disc herniation is responsible for the clinical outcome although the anatomical factor alone is not enough to explain the outcome. The patients with extruded disc herniation shows more morphologic changes on MRI and better clinical outcomes than the patients with protruded discs.

Fitting of a Myoelectric Hand for Wrist Disarticulation

Upper limb amputations usually leave a significant functional limitation in activities of daily living for the amputees despite the use of a conventional prosthesis. New developments in prosthetic design have greatly increased the rehabilitation potential for active individuals with the upper limb amputation. The application of external power to artificial hands and elbow, and elimination of the control cables, the most unpopular feature of body-powered arms, has had a great impact on upper-limb prosthetics in the last two decades. We applied a myoelectric hand to a traumatic amputee with wrist disarticulation. As a result, it was possible to provide a considerable improvement in function and cosmesis with this new device. Further research will undoubtly improve the appearance, function and durability of the present electrically powered myoelectrical hand, making them even more acceptable and useful to the upper limb amputees.

The Value of Radiolographic Assessment in Patellofemoral Pain Syndrome

Patellofemoral pain syndrome (PFS) is one of the most common types of anterior knee pain and many studies reported the patellofemoral malalignments (such as high patella, increased sulcus angle and increased congruence angle) as possible causes of the syndrone. In order to confirm this hypothesis, the difference of congruence, sulcus angles and patella height ratio in normal subjects and PFS patients was evaluated. The PFS subjects were selected according to the criterias of anterior knee pain, pain aggravation after the repeated knee flexion and extension motion. A combined knee injury was screened by MRI. We have compared our data to the previous studies of Merchant et al.(1974), Aglietti et al.(1983), and Dowd and Bently(1986). The radiographic studies were done on lateral view, Merchant view, and patella height was measured by Insall-Salvati method and Blackburn-Peel method. The sulcus angle and the congruence angle were measured on a Merchant view. The results showed that the average patella height of normal group was 1.00+/-0.17 by the Insall test and the patella index was 1.02?0.23. There was no statistical difference between normal and patient group of which the patella height was 0.96+/-0.16 by Insall test with patella index of 1.04?0.17. On Merchant view, the congruence angle was +/-7 +/-11 degrees, and the sulcus angle was 135.5+/-6 degrees in PFS patient group, and in normal group the congruence angle was +/-2 +/-14 degrees, and the sulcus angle was 136+/-5. A little statistical variation was noted in both group. Our results were not much different from previous studies except for the Aglietti's study in congruence angle. We concluded that the Insall test, patella index, congruence angle and sulcus angle could not help to idetify patellofemoral malalignment of knee joint in PFS patients.