The characteristics of F-waves in patients with Kennedy's disease / 中华神经科杂志

ABSTRACT

Objective To investigate the characteristics of F-waves in patients with Kennedy's disease.Methods Thirty two patients with Kennedy's disease and 30 male healthy volunteers,who visited the Department of Neurology,Peking Union Medical College Hospital between August 2013 and July 2014,were recruited consecutively for this study.Motor nerve conduction study and F-wave examination were performed on the median,ulnar,tibial and peroneal nerves of all participants.A series of 100 electrical stimuli were employed to obtain F-waves.The F-wave parameters in all tested nerves were compared between patients with Kennedy's disease and normal controls including F-wave minimum latency,F-wave persistence,mean and maximum F-wave amplitude,the frequency of giant F-waves.Results The mean Fwave amplitude (median nervepatients with Kennedy's disease 375.0 (298.3) μV,healthy volunteers 297.0(145.0) μV,Z =-3.378,P ＜0.01;ulnar nervepatients with Kennedy's disease 397.5(295.0) μV,healthy volunteers 293.0 (101.8) μV,Z =-3.968,P ＜ 0.01;tibial nervepatients with Kennedy's disease 374.5 (227.3) μV,healthy volunteers 294.0 (160.5) μV,Z =-3.144,P =0.002;peroneal nervepatients with Kennedy's disease 346.5 (292.8) μV,healthy volunteers 146.5 (69.3) μV,Z =-6.864,P ＜ 0.01),maximum F-wave amplitudes (median nervepatients with Kennedy's disease 1 291.0 (952.0) μV,healthy volunteers 846.5 (523.0) μV,Z =-4.823,P ＜ 0.01;ulnar nervepatients with Kennedy's disease 1 663.5 (1 374.0) μV,healthy volunteers 760.5 (341.8) μV,Z =-6.813,P ＜ 0.01;tibial nervepatients with Kennedy's disease (1 054.1 ± 451.6) μV,healthy volunteers (652.5-± 172.5) μV,t =5.380,P ＜ 0.01;peroneal nervepatients with Kennedy's disease (840.4 ± 494.1) μV,healthy volunteers (370.2 ± 202.0) μV,t =6.475,P ＜ 0.01),frequency of giant F-waves (median nervepatients with Kennedy's disease 0.0％ (7.2％),healthy volunteers 0.0％ (0.0％),Z =-5.149,P ＜ 0.01;ulnar nervepatients with Kennedy's disease 3.1％ (10.5％),healthy volunteers 0.0％ (0.0％),Z =-7.026,P ＜0.01;tibial nervepatients with Kennedy's disease 0.0％ (3.3％),healthy volunteers 0.0％ (0.0％),Z =-4.651,P ＜0.01;peroneal nervepatients with Kennedy's disease 3.3％ (28.2％),healthy volunteers 0.0％ (0.0％),Z =-5.532,P ＜0.01),and frequencies of patients with giant F-waves (median nervepatients with Kennedy's disease 78.1％ (25/32),healthy volunteers 10.0％ (3/30),x2 =29.016,P ＜ 0.01;ulnar nervepatients with Kennedy's disease 87.5％ (28/32),healthy volunteers 10.0％ (3/30),x2 =37.200,P ＜ 0.01;tibial nervepatients with Kennedy's disease 62.5％ (20/32),healthy volunteers 6.7％ (2/30),x2 =21.085,P ＜ 0.01;peroneal nervepatients with Kennedy's disease 68.8 ％ (22/32),healthy volunteers 10.0％ (3/30),x2 =22.209,P ＜ 0.01) in all nerves examined were significantly higher in patients with Kennedy's disease than in the normal controls.The F-wave persistence in all nerves examined was significantly lower than in the normal controls (median nervepatients with Kennedy's disease 52.5％ (36.3％),healthy volunteers 98.0％ (7.0％),Z =9.010,P ＜ 0.01;ulnar nervepatients with Kennedy's disease 71.0％ (28.3％),healthy volunteers 100.0％ (1.0％),Z =9.455,P ＜ 0.01;tibial nervepatients with Kennedy's disease 100.0％ (2.0％),healthy volunteers 100.0％ (0.0％),Z =4.255,P ＜ 0.01;peroneal nervepatients with Kennedy's disease 33.1％ ± 23.9％,healthy volunteers 46.9％ ± 27.2％,t =-2.848,P =0.007).Giant F-waves were detected in multiple nerves and often appeared symmetrically on the same nerves between the left and right sides in patients with Kennedy's disease.No significant correlations were found between the pooled frequency of giant F-waves and disease duration in patients with Kennedy's disease(r =0.162,P =0.418).Conclusions The results showed increased F-wave amplitudes,increased number of giant F-waves,especially giant F-waves detected in multiple nerves or appearing symmetrically combined with low persistence,consistent with the pathologic features of chronic and unselected loss of anterior horn cells in patients with Kennedy's disease.