The H-reflex to magnetic stimulation of lower-limb nerves

We elicited H-reflexes by magnetic and electrical stimulation of several different nerves in 10 healthy subjects and two patients with S-1 radiculopathy. The posterior tibial nerve at the popliteal fossa and the femoral nerve at the inguinal ligament were tested with both electrical and magnetic stimulation; the proximal sciatic nerve was tested only with magnetic stimulation. Muscle activity was recorded from the soleus muscle for posterior tibial and sciatic nerve stimulation and from the vastus medialis muscle for femoral nerve stimulation. No significant difference was found between the latency of H-reflexes evoked by magnetic or electrical stimulation. With magnetic stimulation, the mean (+/- SD) Ia sensory fiber conduction velocity in the proximal segment of the sciatic nerve was 72.4 +/- 3.3 m/s, while the motor nerve fiber conduction velocity in the same portion of the nerve was significantly slower, at 60.6 +/- 2.0 m/s. In two patients with unilateral S-1 radiculopathy, the latency of the H-reflex from the soleus muscle to both magnetic and electrical stimulation of the posterior tibial nerve was absent or prolonged on the affected side. Magnetic stimulation can be used to study the H-reflex and Ia fiber conduction velocity and is particularly advantageous when testing deeply located nerve trunks.

The proximal tap or "central Tinel" sign in central dysesthetic syndrome after spinal cord injury

Diffuse, chronic, and dysesthetic pain following spinal cord injury (SCI) has been described by several authors under different terms. As illustrated by the two patients described here, central dysesthetic syndrome (CDS) can be mistaken for musculoskeletal, peripheral neuropathic or visceral disease in SCI patients. In these patients, an added clue to the central neuropathic nature of their symptoms was allesthesia and allodynia to light touch or tapping over areas rostral to the level of injury; this may be called the proximal tap or "central Tinel" sign.

Basal ganglia involvement in subacute sclerosing panencephalitis: CT and MR demonstration

We describe a case of subacute sclerosing panencephalitis (SSPE) with clinical parkinsonian features and neuroradiologic abnormalities of the basal ganglia. Prominent basal ganglia involvement may occur in SSPE.