Late resp F H

1. Late responses & Reflexes
•F-wave
•Repeaters
•A-wave
•CMAP followers
•H-reflex
•T-wave
•Blink-reflex
•Flexion-reflex
•Interlimb reflex
•C-wave
Stålberg

2. Generator site for late responses;
F-response
Motor neurone
Single motor axon
Stimulation
Recurrent response
starting at first internode
F-response; infrequent in various normal
axons

3. F-waves - normal

4. F-response generation
antidromic
conduction
SD
invasion
recurrent
impulse

5. F-waves - normal
chronodispersion

6. number of F waves/20 stimuli
2019181716151413121110987654321
NERVE: n.ulnaris
120
100
80
60
40
20
0
Std.
Mean
N = 1
number of F waves/20 stimuli
2019181716151413121110987654321
NERVE: n.ulnaris
120
100
80
60
40
20
0
Std.
Mean
N = 1
number of F waves/20 stimuli
2019181716151413121110987654321
NERVE: n.medianus
40
30
20
10
0
Std. Dev = 4,18
Mean = 15
N = 152,00
number of F waves/20 stimuli
2019181716151413121110987654321
NERVE: n.medianus
40
30
20
10
0
Std. Dev = 4,18
Mean = 15
N = 152,00
Std.Dev = 4.18
Mean = 14.7
N = 152
Std.Dev = 3.31
Mean = 17.5
N = 196
Number of F-waves/20 stimuli in healthy subjectsNumber of F-waves/20 stimuli in healthy subjects
Puuksa, Falck, Stålberg unpubl
Mean = 15,7, range 3-20, -2,5SD= 6
SD = 3,74
N= 482
Mean = 18,1; range 1-20, -2,5 SD 10,4
SD 3,08
N= 485

7. number of F waves/20 stimuli
2019181716151413121110987654321
NERVE: n.peroneus
14
12
10
8
6
4
2
0
Std. Dev = 5,07
Mean = 10
N = 121,00
number of F waves/20 stimuli
2019181716151413121110987654321
NERVE: n.peroneus
14
12
10
8
6
4
2
0
Std. Dev = 5,07
Mean = 10
N = 121,00
number of F waves/20 stimuli
2019181716151413121110987654321
NERVE: n.tibialis
100
80
60
40
20
0
Std.
Mean
N = 1
number of F waves/20 stimuli
2019181716151413121110987654321
NERVE: n.tibialis
100
80
60
40
20
0
Std.
Mean
N = 1
Std.Dev = 2.89
Mean =18.4
N = 125
Std.Dev = 5.07
Mean = 10.1
N = 121
Number of F-waves/20 stimuli in healthy subjectsNumber of F-waves/20 stimuli in healthy subjects
Puuksa, Falck, Stålberg unpubl
Mean 9,27, range 1-20, -2,5SD = 0
N= 221
Mean 18,04; range 1-20, -2,5SD= 8,84
N = 228

8. F-wave persistence in relation to CMAP
ampl (control, ulnar nerve)
mV
# F/20 stim

9. F-waves – diabetic neuropathy

10. N Peroneus
F-waves - conduction blockF-waves - conduction block

11. F-waves - rhizopathyF-waves - rhizopathy

12. Late responsesLate responses (F-waves- H reflexes?)(F-waves- H reflexes?)
–– in spasticityin spasticity

13. 10 ms
1 mV
C6 radiculopathy, right side

14. C6 radiculopathy, right side

15. Left med
Right uln
Right med
Left uln
There are
more F-waves
on right side,
central lesion

16. PLS - ALS
64185

17. PLS - ALS
64185

18. PLS - ALS
64185

19. PLS - ALS
64185

20. F-responses - normal
CMAP n
F ampl n
F # n

21. F-responses - demyelination
CMAP n
F ampl n
F # n

22. F-responses – conduction block
CMAP n
F ampl n
F # few

23. F-responses - normal
CMAP n
F ampl n
F # n

24. F-responses – axonal loss
CMAP 50%
F ampl n
F # 50%

25. F-responses – chronic neurogenic
CMAP n
F ampl 200%
F # 50%

26. F-responses – myopathic condition
CMAP 50%
F ampl 50%
F # n

27. F-responses - spasticity
CMAP n
F ampl 200%
F # 200%
F dispersion

28. Generator site for late responses;
A waves
Motor neurone
Single motor axon
Stimulation
Excitation of a
hyperexcitable site
A-wave; appears after each stimulus
in an affected axon
anywhere along the axon

29. A-waves (and repeater)
N Medianus

30. Intermediate responses
axon reflex extra discharge
(IDD)
ephaps M satellite

32. A-waves in a patient with Guillain Barré syndromeA-waves in a patient with Guillain Barré syndrome
15 year old girl

33. Other mecahnism for late responses;
CMAP satellites
Motor neurone
Single motor axon
Stimulation
Slow conduction in distal axons

34. Moving stimulating electrode
Double stimulation
IDD and M-satellites - different pathophysiology
• IDD channel (K+
defect)
• CMAP-satellites, myelin and axon
IDD and M-satellites can be differentiated

35. CMAP-satellites, terminal slowing
PNP; Tib n. ankle and knee stim

36. 5 ms
5 mV
A
1 mV
10 ms
BUlnar nerve Peroneal nerve
Cholinergic extradischarges (MUSK +) pronounced
(A), slight (B)

37. 2 mV
5 ms
1
10
5 mV
5 ms
pause
Ulnar nerve (MuSK)
Cholinergic extra discharges disappear at 3Hz stim
3 Hz
3 Hz

38. Congenital myasthenia (slow channel)(slow channel)
Stålberg

39. PEMD that remain on 3 Hz RNS
PC, Short exercise
Fournier et al, Ann Neurol. 2004

40. Flexion reflexes
N Peroneus

41. A B
101.2
97.5
97.5
133.8
146.2
216.2
1 mV / div
30 ms / div
0.1 mV / div
30 ms / div
Long latency responses in prior polio
Interlimb reflex (ILR) from VL
at ipsilat plexus stim
Startle response from VL
at contralat plexus stim

42. latency after CMAP
type immediate intermed late
not relaxed,submax stim x
extra discharges x
myotonic discharges(PEMD) x
A-waves x x (x)
CMAP-satellites x x (x)
F-waves x
H-reflex x
flexion reflexes x
ILR x
C-waves x
Late components after the CMAP
Erik Stålberg, Uppsala Sweden