Auditory evoked potential in handled and non-handled iron-deficient rats

Iron deficiency alters metabolism, neurotransmission, glial integrity and the cortical myelin layer, besides increasing myelinization time. Environmental stimulation (handling) improves morphological, biochemical, electrophysiological and behavioral aspects of both well-nourished and malnourished animals. The objective of the present study was to determine the effects of an irondeficient diet and of handling on the brainstem auditory evoked potential (BAEP) of rats during development. Ninety-six male rats were divided since birth into Well-nourished (W, 35 mg iron/kg) and Anemic (A, 4 mg iron/kg) groups, and subdivided into Handling (H) and No Handling (NH). Body weight, hemoglobin (Hb), hematocrit (Ht), latencies of waves I, II, III IV, I-IV interpeak interval, and response threshold to auditory stimuli were evaluated at 18, 22, and 32 days. W animals presented higher Hb and Ht levels than A animals at 18, 22 and 32 days. The animals presented longer latencies of waves I, II, III and IV and I-IV interpeak interval of BAEP at 18 than at 22 and 32 days, and AH18 rats presented longer latencies of waves I and II than AH22 and AH32 rats, and longer wave I latency than WH18 animals. Iron deficiency increased the latencies of BAEP waves, suggesting damage to the myelin layer, especially during the early development, and the effects of handling were more evident along time in anemic animals.

The Diasgnostic Usefulness of Mean F-wave Latency in Diabetic Polyneuropathy

OBJECTIVE: To investigate whether mean F-wave latency is a useful electrodiagnostic test in diabetic patients. METHOD: We examined the diagnostic usefulness of mean F-wave latency, motor nerve conduction velocity (MCV), and amplitude of compound motor nerve action potential (CMAP) of the tibial and peroneal nerves, and of sensory nerve action potential (SNAP) amplitude of the sural nerve in 51 diabetic patients. RESULTS: For the tibial and peroneal nerves, the Z-scores of the mean F-wave latency were significantly larger than those of the MCV and of the amplitude of the CMAP. CONCLUSION: Mean F-wave latency is a sensitive measure for the detection of diabetic polyneuropathy and should be included in electrophysiological studies of diabetic patients.

The usefulness of minimal F-wave latency and sural/radial amplitude ratio in diabetic polyneuropathy

The possibility of whether minimal F-wave latency and a simple ratio between the sural and superficial radial sensory response amplitudes may provide a useful electrodiagnostic test in diabetic patients was investigated in this report. To evaluate the diagnostic sensitivity of minimal F-wave latency, the Z-scores of the minimal F-wave latency, motor nerve conduction velocity (MCV), amplitude of compound muscle action potentials (CMAP), and distal latency (DL) of the median, ulnar, tibial, and peroneal nerve were compared in 37 diabetic patients. For the median, ulnar, and tibial nerves, the Z scores of the minimal F-wave latency were significantly larger than those of the MCV. In addition for all four motor nerves, the Z scores of the minimal F-wave latency were significantly larger than those for the CMAP amplitude. Furthermore, 19 subjects showing abnormal results in the standard sensory nerve conduction study had a significantly lower sural/radial amplitude ratio (SRAR), and 84% of them had an SRAR of less than 0.5. In conclusion, minimal F-wave latency and the ratio between the amplitudes of the sural and superficial radial sensory nerve action potential are sensitive measures for the detection of nerve pathology and should be considered in electrophysiologic studies of diabetic polyneuropathy.