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Importance of sample size for the estimation of repeater F waves in amyotrophic lateral sclerosis.

Fang J, Liu MS, Guan YZ, Cui B, Cui LY - Chin. Med. J. (2015)

Bottom Line: For each group, the Index RN and Index Freps obtained from 20 and 100 stimuli were compared.In the P group, the Index RN (P = 0.004) and Index Freps (P = 0.001) obtained from 100 stimuli were significantly higher than from 20 stimuli.For F waves obtained from 20 stimuli, no significant differences were identified between the P and NP groups for Index RN (P = 0.052) and Index Freps (P = 0.079); The Index RN (P < 0.001) and Index Freps (P < 0.001) of the P group were significantly higher than the control group; The Index RN (P = 0.002) of the NP group was significantly higher than the control group.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China.

ABSTRACT

Background: In amyotrophic lateral sclerosis (ALS), repeater F waves are increased. Accurate assessment of repeater F waves requires an adequate sample size.

Methods: We studied the F waves of left ulnar nerves in ALS patients. Based on the presence or absence of pyramidal signs in the left upper limb, the ALS patients were divided into two groups: One group with pyramidal signs designated as P group and the other without pyramidal signs designated as NP group. The Index repeating neurons (RN) and Index repeater F waves (Freps) were compared among the P, NP and control groups following 20 and 100 stimuli respectively. For each group, the Index RN and Index Freps obtained from 20 and 100 stimuli were compared.

Results: In the P group, the Index RN (P = 0.004) and Index Freps (P = 0.001) obtained from 100 stimuli were significantly higher than from 20 stimuli. For F waves obtained from 20 stimuli, no significant differences were identified between the P and NP groups for Index RN (P = 0.052) and Index Freps (P = 0.079); The Index RN (P < 0.001) and Index Freps (P < 0.001) of the P group were significantly higher than the control group; The Index RN (P = 0.002) of the NP group was significantly higher than the control group. For F waves obtained from 100 stimuli, the Index RN (P < 0.001) and Index Freps (P < 0.001) of the P group were significantly higher than the NP group; The Index RN (P < 0.001) and Index Freps (P < 0.001) of the P and NP groups were significantly higher than the control group.

Conclusions: Increased repeater F waves reflect increased excitability of motor neuron pool and indicate upper motor neuron dysfunction in ALS. For an accurate evaluation of repeater F waves in ALS patients especially those with moderate to severe muscle atrophy, 100 stimuli would be required.

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The comparison of repeater F waves among the P, NP and control groups and the comparison of repeater F waves obtained from 20 with those from 100 stimuli for each group. The edges indicate the 25th and 75th percentile. The open circle (o) designates values below or above 1.5 box-lengths from the box-edges, and the asterisk (*) designate values below or above 3.0 box-lengths from the box-edges. (a) Index RN; (b) Index Freps (*P < 0.05, **P < 0.01). P: Limbs with pyramidal signs; NP: Limbs without pyramidal signs; C: Control group; RN: Repeating neuron.
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Figure 1: The comparison of repeater F waves among the P, NP and control groups and the comparison of repeater F waves obtained from 20 with those from 100 stimuli for each group. The edges indicate the 25th and 75th percentile. The open circle (o) designates values below or above 1.5 box-lengths from the box-edges, and the asterisk (*) designate values below or above 3.0 box-lengths from the box-edges. (a) Index RN; (b) Index Freps (*P < 0.05, **P < 0.01). P: Limbs with pyramidal signs; NP: Limbs without pyramidal signs; C: Control group; RN: Repeating neuron.

Mentions: In the P group, the Index RN (P = 0.004) and Index Freps (P = 0.001) obtained from 100 stimuli were significantly higher than from 20 stimuli. In the NP group, there were no significant differences between the Index RN (P = 0.244) or Index Freps (P = 0.183) obtained from 20 and 100 stimuli. In the control group, the Index RN (P = 0.02) and Index Freps (P = 0.018) obtained from 100 stimuli were significantly higher than from 20 stimuli. For F waves obtained from 20 stimuli, no significant differences were identified between the P and NP groups for Index RN (P = 0.052) and Index Freps (P = 0.079); The Index RN (P < 0.001) and Index Freps (P < 0.001) of the P group were significantly higher than the control group; The Index RN (P = 0.002) of the NP group was significantly higher than the control group; There was no significant difference between the NP and control groups for the Index Freps (P = 0.023). For F waves obtained from 100 stimuli, the Index RN (P < 0.001) and Index Freps (P < 0.001) of the P group were significantly higher than the NP group; The Index RN (P < 0.001) and Index Freps (P < 0.001) of the P group were significantly higher than the control group; The Index RN (P < 0.001) and Index Freps (P < 0.001) of the NP group were significantly higher than the control group [Figure 1]. The maximum number of individual repeater F waves have required at least 80 stimuli in 90% ALS patients of the P group, 67% ALS patients of the NP group and 82% subjects of the control group.


Importance of sample size for the estimation of repeater F waves in amyotrophic lateral sclerosis.

Fang J, Liu MS, Guan YZ, Cui B, Cui LY - Chin. Med. J. (2015)

The comparison of repeater F waves among the P, NP and control groups and the comparison of repeater F waves obtained from 20 with those from 100 stimuli for each group. The edges indicate the 25th and 75th percentile. The open circle (o) designates values below or above 1.5 box-lengths from the box-edges, and the asterisk (*) designate values below or above 3.0 box-lengths from the box-edges. (a) Index RN; (b) Index Freps (*P < 0.05, **P < 0.01). P: Limbs with pyramidal signs; NP: Limbs without pyramidal signs; C: Control group; RN: Repeating neuron.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4836257&req=5

Figure 1: The comparison of repeater F waves among the P, NP and control groups and the comparison of repeater F waves obtained from 20 with those from 100 stimuli for each group. The edges indicate the 25th and 75th percentile. The open circle (o) designates values below or above 1.5 box-lengths from the box-edges, and the asterisk (*) designate values below or above 3.0 box-lengths from the box-edges. (a) Index RN; (b) Index Freps (*P < 0.05, **P < 0.01). P: Limbs with pyramidal signs; NP: Limbs without pyramidal signs; C: Control group; RN: Repeating neuron.
Mentions: In the P group, the Index RN (P = 0.004) and Index Freps (P = 0.001) obtained from 100 stimuli were significantly higher than from 20 stimuli. In the NP group, there were no significant differences between the Index RN (P = 0.244) or Index Freps (P = 0.183) obtained from 20 and 100 stimuli. In the control group, the Index RN (P = 0.02) and Index Freps (P = 0.018) obtained from 100 stimuli were significantly higher than from 20 stimuli. For F waves obtained from 20 stimuli, no significant differences were identified between the P and NP groups for Index RN (P = 0.052) and Index Freps (P = 0.079); The Index RN (P < 0.001) and Index Freps (P < 0.001) of the P group were significantly higher than the control group; The Index RN (P = 0.002) of the NP group was significantly higher than the control group; There was no significant difference between the NP and control groups for the Index Freps (P = 0.023). For F waves obtained from 100 stimuli, the Index RN (P < 0.001) and Index Freps (P < 0.001) of the P group were significantly higher than the NP group; The Index RN (P < 0.001) and Index Freps (P < 0.001) of the P group were significantly higher than the control group; The Index RN (P < 0.001) and Index Freps (P < 0.001) of the NP group were significantly higher than the control group [Figure 1]. The maximum number of individual repeater F waves have required at least 80 stimuli in 90% ALS patients of the P group, 67% ALS patients of the NP group and 82% subjects of the control group.

Bottom Line: For each group, the Index RN and Index Freps obtained from 20 and 100 stimuli were compared.In the P group, the Index RN (P = 0.004) and Index Freps (P = 0.001) obtained from 100 stimuli were significantly higher than from 20 stimuli.For F waves obtained from 20 stimuli, no significant differences were identified between the P and NP groups for Index RN (P = 0.052) and Index Freps (P = 0.079); The Index RN (P < 0.001) and Index Freps (P < 0.001) of the P group were significantly higher than the control group; The Index RN (P = 0.002) of the NP group was significantly higher than the control group.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China.

ABSTRACT

Background: In amyotrophic lateral sclerosis (ALS), repeater F waves are increased. Accurate assessment of repeater F waves requires an adequate sample size.

Methods: We studied the F waves of left ulnar nerves in ALS patients. Based on the presence or absence of pyramidal signs in the left upper limb, the ALS patients were divided into two groups: One group with pyramidal signs designated as P group and the other without pyramidal signs designated as NP group. The Index repeating neurons (RN) and Index repeater F waves (Freps) were compared among the P, NP and control groups following 20 and 100 stimuli respectively. For each group, the Index RN and Index Freps obtained from 20 and 100 stimuli were compared.

Results: In the P group, the Index RN (P = 0.004) and Index Freps (P = 0.001) obtained from 100 stimuli were significantly higher than from 20 stimuli. For F waves obtained from 20 stimuli, no significant differences were identified between the P and NP groups for Index RN (P = 0.052) and Index Freps (P = 0.079); The Index RN (P < 0.001) and Index Freps (P < 0.001) of the P group were significantly higher than the control group; The Index RN (P = 0.002) of the NP group was significantly higher than the control group. For F waves obtained from 100 stimuli, the Index RN (P < 0.001) and Index Freps (P < 0.001) of the P group were significantly higher than the NP group; The Index RN (P < 0.001) and Index Freps (P < 0.001) of the P and NP groups were significantly higher than the control group.

Conclusions: Increased repeater F waves reflect increased excitability of motor neuron pool and indicate upper motor neuron dysfunction in ALS. For an accurate evaluation of repeater F waves in ALS patients especially those with moderate to severe muscle atrophy, 100 stimuli would be required.

Show MeSH
Related in: MedlinePlus