Cross Sectional Survey Of Patients With ALS/MND In Clinic And Clinical, Electrophysiological Features

Background:Amyotrophic lateral sclerosis (ALS)/motor neuron disease (MND) is a neurodegenerative disease characterized by progressive muscular paralysis reflecting degeneration of motor neurons in the primary motor cortex, corticospinal tracts, brainstem and spinal cord. Annual incidence rate is 0.4-1.76/100,000. Overall, there is a slight higher male prevalence (M:F ratio～1.5:1). Electrophysiological examination is an important method to diagnose ALS/MND. At present, our country is still lack of epidemiological data of such disease.Purpose:We sought to analyze the percentage, clinical type composition and the electrophysiological characteristics of ALS/MND patients in neurological clinic of Qilu hospital.Methods:We collected patients diagnosed ALS/MND between February 1,2009 and July 31, 2009 in neurological clinic of Qilu hospital, and then analyzed clinical type composition and the electrophysiological characteristics. Patients consistent with revised El Escorial criteria were included in this study, and patients with following features were also included,①onset age> 30 years old;②history>3 months,<36 months;③physical examination showed upper motor neuron (UMN) involvement only or little upper motor neuron involvement;④electromyography (EMG) showed widespread neurogenic damage, namely, two or more segments appeared dominated by denervated muscle potential, increased motor unit potential (MUP)/abnormal recruitment.Results:41 patients were diagnosed as ALS/MND during February 1,2009 to July 31, 2009 in neurological clinic at our hospital (36,000 outpatients over the same period), and male to female ratio is 2.15:1 (28 male patients,13 female patients). There were 28 cases with UMN involvement including 20 cases of limb onset ALS and 8 cases of bulbar onset ALS, and the interval from symptom onset to diagnosis were respectively 18.2 months (3.5-48 months,13 patients in 12-24 months) and 7.6 months (3.5-12 months), with the significant difference (P<0.05). In these 28 patients,2 patients were diagnosed as definite ALS and 12 patents were diagnosed as probable ALS according to revised El Escorial criteria. Of 41 patients,8 cases were progressive spinal muscular atrophy (PMA); 3 cases were flail arm syndrome; 1 case was flail leg syndrome; 1 case was primary lateral sclerosis (PLS). All patients'EMG showed widespread neurogenic damage, namely, two or more segments appear dominated by denervated muscle potential, increased motor unit potential/abnormal recruitment. However, of 176 muscles examined in 41 patients, there were only 7 muscles showing giant MUPs, comparing with 83 muscles showing normal MUPs and 86 muscles with slightly increased MUPs. Nerve conduction studies showed that 66.7% of patients had decreased compound muscle action potential (CMAP) and 66.7% of patients had declined occurrence rate of F wave.Conclusions:1. Of all outpatients in neurological clinic of Qilu hospital, the ratio of ALS/MND patients is about 0.11%, and the number of male patients is about 2 times comparing with the number of female patients.2. About half of the ALS/MND patients showed limb onset ALS, while bulbar onset ALS and PMA had the same proportion, however, the remaining variants were relatively rare.3. Bulbar onset ALS patients had a shorter interval while diagnosis compared with limb onset ALS, reflecting the rapid progression of this type.4. Only one-third of ALS/MND patients can be diagnosed according to clinical manifestation alone, revealing the necessity of the electrophysiological examination, which can detect the subclinical lesions, diagnose the ALS/MND variants and exclude of other types of lower motor neuron syndrome. 5. Analysis of MUP from these patients showed that the giant potential was uncommon in patients with ALS/MND.