Demographics, including sex, age of onset, occupation, past neuropsychological and other substance consumption history, history of N2O use, onset-to-admission time, ways of admission to the hospital, length of hospital stay, abnormal events during hospitalization, recovery status at discharge, and records of natural follow-up at our outpatient clinic were collected. The history of N2O use consists of the length of exposure, the recent increase in use, and the concealment of N2O consumption at the first admission.
Neurological symptoms and signs were comprehensively assessed during hospitalization. Based on the clinical evaluations, the functional disability rating score (FDRS) was calculated by two experienced neurologists. The score has been used widely in the clinical severity evaluation of SCDs, including N2O-related neuropathies (11 (link), 13 (link), 14 (link)). The five-part scoring system is described as follows: (1) gait (0 = normal, 1 = positive Romberg's sign, 2 = impaired but able to walk unsupported, 3 = substantial support required for ambulation, 4 = wheelchair-bound or bedridden); (2) sensory disturbances including hypesthesia, dysesthesia, vibration/joint-position impairment (0 = normal, 1 = impairment only in toes and fingers, 2 = impairment in the ankles and wrists, 3 = impairment in the upper arms and legs); (3) mental impairment (0 = normal, 1 = intellectual or behavioral impairment requiring no social support, 2 = partial dependence for all activities of daily living, 3 = complete dependence for all activities of daily living); (4) neuropathy (0 = normal reflex, 1 = loss or reduction of deep tendon reflexes of the ankle, 2 = loss or reduction of deep tendon reflexes of the patella, 3 = loss or reduction of deep tendon reflexes of the biceps); and (5) pyramidal tract signs (0 = normal, 1 = positive Babinski sign, 2 = spastic paraparesis, 3 = spastic tetraparesis). The cumulative score ranges from 0 to 16. A higher score indicated increased severity of neurological impairment and a worse functional status of a patient.
Neurological symptoms and signs were comprehensively assessed during hospitalization. Based on the clinical evaluations, the functional disability rating score (FDRS) was calculated by two experienced neurologists. The score has been used widely in the clinical severity evaluation of SCDs, including N2O-related neuropathies (11 (link), 13 (link), 14 (link)). The five-part scoring system is described as follows: (1) gait (0 = normal, 1 = positive Romberg's sign, 2 = impaired but able to walk unsupported, 3 = substantial support required for ambulation, 4 = wheelchair-bound or bedridden); (2) sensory disturbances including hypesthesia, dysesthesia, vibration/joint-position impairment (0 = normal, 1 = impairment only in toes and fingers, 2 = impairment in the ankles and wrists, 3 = impairment in the upper arms and legs); (3) mental impairment (0 = normal, 1 = intellectual or behavioral impairment requiring no social support, 2 = partial dependence for all activities of daily living, 3 = complete dependence for all activities of daily living); (4) neuropathy (0 = normal reflex, 1 = loss or reduction of deep tendon reflexes of the ankle, 2 = loss or reduction of deep tendon reflexes of the patella, 3 = loss or reduction of deep tendon reflexes of the biceps); and (5) pyramidal tract signs (0 = normal, 1 = positive Babinski sign, 2 = spastic paraparesis, 3 = spastic tetraparesis). The cumulative score ranges from 0 to 16. A higher score indicated increased severity of neurological impairment and a worse functional status of a patient.
Free full text: Click here
