RESUMEN
Background: HTLV-I associated myelopathy/tropical spastic paraparesis (HAM/TSP) is a defined entity. However, there are many patients not well characterized with a similar clinical picture who are HTLV-I seronegative. Objective: Clinical and neurophysiological description of patients with HTLV-I seronegative idiopathic paraparesia. Patients and Methods: Seventeen patients (4 women and 13 men aged 24-67 years, average 52.3) were evaluated including clinical assessment, vibratory sensory analysis, quantitative somatosensory thermotest (QST), somatosensory evoked potentials (SSEPs), electromyography (EMG) and motor and sensory nerve conductions. Results: In addition to the spastic paraparesis, 3 (17.6 percent) patients had pseudobulbar symptoms. Ten (58.8 percent) patients had a spastic gait but could walk unaided, 6 (35.2 percent) needed support and 1 patient could not walk. Bladder dysfunction was found in 10 (58.8) patients and sensory symptoms in 7 (41.1 percent). There was mild distal impairment of vibration and position sense, distal tactile and pinprick hypoesthesia in 4 (23.4 percent) patients. Tibial SSEPs were abnormal in 11 (64.7 percent). Nerve conduction studies and EMG were normal. QST showed cold hypoesthesia in 14 (82.4 percent) patients. Warm sensation and heat pain appeared unimpaired. Conclusions: All sensory abnormalities found were restricted to sensations carried by myelinated (A beta and A delta) channels. Sensory and motor abnormalities are similar to HAM/TSP patients suggesting a common pathogenesis