Electrophysiological indices of central and peripheral nervous system function during theophylline therapy

Electrophysiological parameters including the EEG, somatosensory evoked potentials (SEP), F waves, long loop reflexes and peripheral nerve conduction velocities were assessed during the 15th week of theophylline therapy, with serum levels maintained in the low therapeutic range, in young, healthy male volunteers (n = 7). Recordings were repeated 1 week after vitamin B6 supplementation and finally 6-7 weeks after the cessation of medication. Alpha amplitudes were significantly lower during theophylline therapy compared to the posttreatment baseline recording. The SEP findings failed to reveal any significant differences between the three recordings, as was the case with peripheral nerve conduction velocities and long loop reflexes. The average F wave latencies during theophylline therapy were significantly shorter, and the percentage F waves recorded was higher, compared to the baseline recordings. These findings suggest that relatively long-term theophylline therapy has stimulatory effects on aspects of electrical activity in the brain and spinal cord. These effects appeared to be unchanged after vitamin B6 supplementation for 1 week.