Pulsed Electromagnetic Fields Alter Calcium & Functional Recovery in Spinal Cord Injury

Modulated electromagnetic fields have long been known to alter CNS calcium. Depending on the frequency and intensity of the fields applied, both the release and uptake of neuronal Ca have been reported. Ca ions are intracellular messengers of many neuronal functions. Here we report evidence for a significant reduction of Ca accumulation in injured cat spinal cords by pulsed electromagnetic fields (PEMF) and a possible therapeutic effect on neurological recovery by this treatment.

We examined the distribution of spinal cord CA by atomic absorption spectroscopy. 3 hours after injury in 21 cats, divided into 3 equal groups: (1) uninjured controls, (2) injured, (3) injured and PEMF treated. The injury was by a 13-gram weight dropped 20 cm onto T9 cord exposed by laminectomy and supported by a rigidly clamped spinal column. This model produces severe spinal injury, causing consistent paraplegia for more than 6 months after injury. We applied PEMF with an instrument (Diapulse, N.Y.) which radiates 400/sec 50usec pulses of radio frequency (27.8 MHz) field (98 mW/ per sq.cm. average power) centered on the injury site at 45-165 minutes after injury. Mean concentrations are listed with standard deviations (n=7).

PEMF significantly reduced peaks of Ca in the cord adjacent to the lesion site.

In a separate series, we evaluated for 5 months the neurophysiological and motor recovery of 27 cats, in three groups: (1) injured controls, (2) injured and PEMF treated, (3) injured and treated with a 30 mg/kg methylprednisolone (MP) IV 45 minutes after injury. 50% of the PEMF treated cats walked independently by 4 months after injury, compared with one of the untreated cats and one of the MP cats. PEMF cats had significantly larger mean somatosensory evoked potential and vestibulospinal response amplitudes than MP-treated or control cats. Quantitative studies are under way.