**1.9 Problems with volume conduction**

*Proprioception*

**46**

**Figure 7.**

*"H-reflexes" of the A) peroneus longus and B) extensor hallucis longus muscles by stimulation of the common peroneal nerve and recorded with surface electrodes. In reality" H-reflexes" may be H-reflexes of the triceps surae muscle caused by spreading of stimuli to a branch of the posterior tibial nerve. Calibration 10 ms/div, 3 mV/div.*

When the common peroneal nerve is stimulated, the stimulus spreads readily to the motor branches of the posterior tibial nerve. Thus, volume conduction is a source of error especially when the reflexes of the pretibial muscles are recorded with surface electrodes. The stimulation spreading to branches of the posterior tibial nerve may elicit H-reflex of the triceps surae muscle, recorded with electrodes on the surface of the anterior tibial muscle. This reflex response may imitate the myotatic reflex of the anterior tibial muscle (**Figure 6**). A similar problem may be encountered by recording of responses of the peroneus longus and extensor hallucis longus muscles (**Figure 7**), as well as the foot muscles (**Figure 8**). However a

#### **Figure 8.**

*F-responses of the tibial nerve in the abductor hallucis brevis muscle, latency 50 ms. stimulation at the ankle, upper 10 responses with surface electrodes. The lower 10 sweeps are recorded from the extensor digitorum brevis muscle: A) with a concentric needle electrode, no responses, and B) with surface electrodes, active electrode on the muscle and reference placed in the distal end of 5th metatarsal bone. Observe the "medium latency reflexes" of the extensor digitorum brevis muscle, which are volume conducted F-responses of the abductor hallucis brevis muscle. Calibration: 10 ms /div, 2 mV / div.*

#### **Figure 9.**

*Stimulation of the common peroneal nerve at the fibular head. Uppermost: M-response of the anterior tibial muscle recorded with surface electrodes. Lowermost: Possible medium latency reflex responses of the abductor digiti minimi muscle, latency 85 ms (vertical line). But the volume conducted F-responses of the extensor digitorum brevis muscle might be another possibility (see Figure 7B). However, the F-response latency should be essentially shorter than this recorded response, with stimulation at the fibular head. Calibration 20 ms/div, 2 mV/div.*

#### **Figure 10.**

*H-reflex of the soleus muscle, latency 29.8 ms, stimulation of* n. tibialis *at the popliteal space (uppermost sweeps). When the stimulation was changed to the common peroneal nerve (lowermost sweeps), "H-reflex" of the peroneus longus muscle was elicited (arrow). But we may also see a medium latency reflex response of about 64 ms (vertical line), which cannot be elicited from the peroneal muscles. This proves that a branch of the tibial nerve leading possibly to the lateral gastrocnemius muscle, with medium latency reflex response is also activated by the stimulation. Calibration 8 ms/div, 1 mV/div.*

**49**

**Author details**

Juhani Partanen1

\*, Urho Sompa2

in the context of full clinical picture.

Jorvi Hospital, Rörstrandinkatu 4 B 27, 00560, Helsinki, Finland

peroneus longus muscle. L3 and L4 posterior roots might be investigated with the quadriceps femoris and adductor H-reflexes. Considering these many different methods and technical challenges related to them, a practitioner is advised to collect own normative data and always interpret the results rather conservatively

Keskussairaalantie 19, PL 123, 40620, Jyväskylä, Finland

\*Address all correspondence to: junipartanen@gmail.com

provided the original work is properly cited.

and Miguel Muñoz-Ruiz<sup>2</sup>

1 Department of Clinical Neurophysiology, University Central Hospital of Helsinki,

2 Department of Clinical Neurophysiology, Central Finland Health Care District,

© 2021 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

*Recording of Proprioceptive Muscle Reflexes in the Lower Extremity*

H-reflex" of the peroneus longus muscle (**Figure 10**).

medium latency reflex response of the abductor digiti minimi muscle may really occur (**Figure 9**). The medium latency reflex response may reveal the false"

The H-reflex is a useful tool as a probe for clinical neurophysiologist, but the pathways and pitfalls should be considered [12]. The integrity of posterior roots of the S1 level is readily studied with the soleus H-reflex measurement, and we have used this method routinely for a long time. Unfortunately, there are difficulties with recording of H-reflex of the L5 level. Our trials with surface electrodes were often hampered by volume conducted reflex responses of the triceps surae muscle. With a simultaneous needle recording of the peroneus longus muscle we could prove that the H-reflex response of it is real, but it should be distinguished from F-responses. The medium latency reflex of the soleus muscle can be recorded with a powerful twitch contraction of the pretibial muscles elicited by supramaximal stimulation of the common peroneal nerve. We do not have any experience of its use in S1 root syndrome diagnostics. However, it is tempting to assume, that we may study the integrity of two completely different parallel proprioceptive reflex arches of the soleus muscle: the Ia-afferent – α efferent reflex arch (H-reflex), as well as the II-afferent – β efferent reflex arch (medium latency reflex), and compare the results of these measurements in investigation of the posterior root syndrome at S1 level. H-reflex of the peroneus longus muscle might be used in the diagnostics of posterior root lesion of the L5 level. We recommend the recording of this reflex with an EMG needle electrode. This recording can be performed accompanied with the needle EMG study for a possible axonal injury of the L5 motor nerve fibres of the

*DOI: http://dx.doi.org/10.5772/intechopen.95575*

**2. Conclusions**

medium latency reflex response of the abductor digiti minimi muscle may really occur (**Figure 9**). The medium latency reflex response may reveal the false" H-reflex" of the peroneus longus muscle (**Figure 10**).
