The Effects of Stimulation Frequency Changes on Central Conduction Time in Short Latency SEPs in Multiple Sclerosis Patients.
Background: Somatosensory evoked potentials (SEPs) are widely used in the electrophysiological diagnosis of multiple sclerosis since 1970s The importance of central conduction time among SEP parameters is also well known and it is often regarded as being pathological more often than the absolute...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Galenos Yayinevi
2005-02-01
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| Series: | Türk Nöroloji Dergisi |
| Subjects: | |
| Online Access: | https://www.journalagent.com/tjn/pdfs/TJN_11_1_45_53.pdf |
| Summary: | Background: Somatosensory evoked potentials (SEPs) are widely used
in the electrophysiological diagnosis of multiple sclerosis since 1970s The importance of central conduction time among SEP parameters is
also well known and it is often regarded as being pathological more
often than the absolute latencies.
Objective: In this study our aim was to find out the effects of the
change of stimulus frequencies on absolute latencies and central
conduction time in median SEPs of multiple sclerosis patients.
Material and method: Twenty five multiple sclerosis patients and 15
healthy subjects were taken into the study and median SEPs of 80
extremities were studied. During median SEP recordings the stimulus
frequencies were changed by 2/sec, 4/sec, 6/sec and 9/sec both in
the patient and control groups. N9 peak, N11 peak, N13 peak, N20
peak and N11-13 complex onset latency, N20 onset latency, peak
central conduction time and onset central conduction time have been
determined both in the patient and the control groups. All the
parameters of different stimulation frequencies were compared
statistically with each other both in the patient and the control groups.
The parameters of the patient and the control groups were also
compared statistically with one and other.
Results: The results showed that N20 peak latency, peak central
conduction time, N20 onset latency and onset central conduction time
values were statistically significantly higher in the patient group when
compared with the control group. In the patient group, the values of
peak central conduction time in 4/sec stimulation frequency were
statistically significantly higher than the values in 2/sec stimulation
frequency (p<0.01). The same was true for the values in 6/sec stimulation
frequency when compared with the values in 2/sec stimulation frequency
(p<0.05). There were no such statistically significant results for peak
central conduction time values of the control group when different
stimulation frequencies were applied (p>0.05). In the patient group,
the values of onset central conduction time in 4/sec stimulation
frequency were statistically significantly higher than the values in 2/sec
stimulation frequency (p<0.05). The values in the control group did
not show any statistical differences again (p>0.05).
Conclusions: The results obtained in this study showed us that the
change of the stimulation frequencies in the patient group enhanced
the pathology seen in both peak and central conduction times whereas
the normal controls were immune to this effect. Changing the stimulation
frequency during short latency SEP recordings has not been studied
in multiple sclerosis patients before. We believe that studies on stimulus
frequency changes in SEPs in multiple sclerosis, will be very useful both
for the electrophysiological diagnosis of MS and the physiological
dynamics of SEPs. |
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| ISSN: | 1301-062X 1309-2545 |