**2. Characteristics of H-reflex and F-wave patterns resulting from increased stimulus intensity during muscle relaxation**

The H-reflex and F-wave of the affected arm were examined under conditions of increased stimulus intensity during muscle relaxation in 31 patients (17 male and 14 female) with hemiplegia caused by CVD. The mean patient age was 56 years (range: 30–82 years). Eighteen patients had cerebral infarction (7 with right and 11 with left hemiplegia) and 13 had cerebral hemorrhage (7 with right and 6 with left). The control group included 30 healthy subjects with a mean age of 56.2 years (range: 28–80 years). Written informed consent was obtained from all subjects. The experiments were conducted in accordance with the Declaration of Helsinki, and no conflicts of interest were declared by the authors.

Figure 1. Measurement<\$%&?>of<\$%&?>the<\$%&?>H-reflex<\$%&?>and<\$%&?>F-wave

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27

In<\$%&?>type<\$%&?>1,<\$%&?>the<\$%&?>F-

R+: Recording Electrode (+), R−: Recording Electrode (−) S+: Stimulating Electrode (+), S−: Stimulating Electrode (−)

**Figure 1.** Measurement of the H-reflex and F-wave

F-wave<\$%&?>(Fig<\$%&?>5).

increased stimulus intensity; there was no F-wave (Fig 5).

>no<\$%&?>H-reflex<\$%&?>(Fig<\$%&?>2).<\$%&?>The<\$%&?>F-

In type 1, the F-wave appeared with increased stimulus intensity, but there was no H-reflex (Fig 2). The F-wave pattern for the upper arm, especially the distal portion in healthy subjects, roughly indicated a type 1 pattern. In type 2, the H-reflex and F-wave both appeared with increased stimulus intensity, but the F-wave followed the disappearance of the H-reflex (Fig 3). In type 3, the H-reflex and F-wave both appeared with increased stimulus intensity, but the F-wave appeared during the H-reflex (Fig 4). In type 4, only the H-reflex appeared with

F-wave<\$%&?>appeared<\$%&?>during<\$%&?>the<\$%&?>H-

\$%&?>type<\$%&?>2,<\$%&?>the<\$%&?>H-reflex<\$%&?>and<\$%&?>F-

F-wave<\$%&?>followed<\$%&?>the<\$%&?>disappearance<\$%&?>of<\$%&?>the<\$%&?>H-

reflex<\$%&?>(Fig<\$%&?>4).<\$%&?>In<\$%&?>type<\$%&?>4,<\$%&?>only<\$%&?>the<\$%&?>H-

R+:<\$%&?>Recording<\$%&?>Electrode<\$%&?>(+),<\$%&?>R−:<\$%&?>Recording<\$%&?>Electrode<\$%&?>(−)

S+:<\$%&?>Stimulating<\$%&?>Electrode<\$%&?>(+),<\$%&?>S−:<\$%&?>Stimulating<\$%&?>Electrode<\$%&?>(−)

reflex<\$%&?>(Fig<\$%&?>3).<\$%&?>In<\$%&?>type<\$%&?>3,<\$%&?>the<\$%&?>H-reflex<\$%&?>and<\$%&?>F-

wave<\$%&?>appeared<\$%&?>with<\$%&?>increased<\$%&?>stimulus<\$%&?>intensity,<\$%&?>but<\$%&?>there<\$%&?>was<\$%&?

wave<\$%&?>pattern<\$%&?>for<\$%&?>the<\$%&?>upper<\$%&?>arm,<\$%&?>especially<\$%&?>the<\$%&?>distal<\$%&?>portion<\$ %&?>in<\$%&?>healthy<\$%&?>subjects,<\$%&?>roughly<\$%&?>indicated<\$%&?>a<\$%&?>type<\$%&?>1<\$%&?>pattern.<\$%&?>In<

wave<\$%&?>both<\$%&?>appeared<\$%&?>with<\$%&?>increased<\$%&?>stimulus<\$%&?>intensity,<\$%&?>but<\$%&?>the<\$%&?>

wave<\$%&?>both<\$%&?>appeared<\$%&?>with<\$%&?>increased<\$%&?>stimulus<\$%&?>intensity,<\$%&?>but<\$%&?>the<\$%&?>

reflex<\$%&?>appeared<\$%&?>with<\$%&?>increased<\$%&?>stimulus<\$%&?>intensity;<\$%&?>there<\$%&?>was<\$%&?>no<\$%&?>

Examination was performed in a supine, relaxed position. H-reflex and F-wave data under conditions of increased stimulus intensity following median nerve stimulation at the wrist were recorded at the opponens pollicis muscle, which was in a relaxed state, of the affected arm of the CVD patients or the right arm of the healthy subjects (Fig 1). The stimulus frequency was 0.5 Hz and the stimulus duration was 0.2 ms. H-reflex and F-wave patterns that resulted from increased stimulus intensity were divided into 4 types (types 1–4).

Figure 1. Measurement<\$%&?>of<\$%&?>the<\$%&?>H-reflex<\$%&?>and<\$%&?>F-wave R+: Recording Electrode (+), R−: Recording Electrode (−) S+: Stimulating Electrode (+), S−: Stimulating Electrode (−)

F-wave<\$%&?>(Fig<\$%&?>5).

#### **Figure 1.** Measurement of the H-reflex and F-wave

measuring the F-wave in CVD patients with hypertonus and hyperreflexia. As a result, the H-reflex can be mistaken for an F-wave during F-wave measurement using supramaxi‐

We hypothesized that evaluation of F-wave and H-reflex patterns resulting from in‐ creased stimulus intensity in CVD patients could be a potential new method for the neurological evaluation of the affected arm or leg. In this report, we investigated the excitability of spinal neural function by evaluating H-reflex and F-wave patterns result‐ ing from increased stimulus intensity during muscle relaxation in healthy subjects and CVD patients. The results were analyzed in terms of the characteristic appearance of the Hreflex and F-wave in the healthy subjects and the relationship between the neurological findings of CVD and the characteristic appearance of the H-reflex and F-wave in the CVD

In the field of rehabilitation medicine, muscle stretching is generally used to increase range of motion and improve muscle tonus. The effects of leg muscle stretching have been previously evaluated using H-reflex data (Angel et al., 1963 and Nielsen et al., 1993), and the results showed that the H-reflex following passive stretching was decreased to a lesser extent in spastic patients than in healthy subjects. However, in that study, the calf muscles and not the arm muscles were stretched; moreover, the periods of continuous stretching were differ‐ ent.Therefore, we also investigated the effects of continuous stretching of the affected arm for 1 min by evaluating H-reflex and F-wave characteristics in different stretched arm positions

**2. Characteristics of H-reflex and F-wave patterns resulting from increased**

The H-reflex and F-wave of the affected arm were examined under conditions of increased stimulus intensity during muscle relaxation in 31 patients (17 male and 14 female) with hemiplegia caused by CVD. The mean patient age was 56 years (range: 30–82 years). Eighteen patients had cerebral infarction (7 with right and 11 with left hemiplegia) and 13 had cerebral hemorrhage (7 with right and 6 with left). The control group included 30 healthy subjects with a mean age of 56.2 years (range: 28–80 years). Written informed consent was obtained from all subjects. The experiments were conducted in accordance with the Declaration of Helsinki, and

Examination was performed in a supine, relaxed position. H-reflex and F-wave data under conditions of increased stimulus intensity following median nerve stimulation at the wrist were recorded at the opponens pollicis muscle, which was in a relaxed state, of the affected arm of the CVD patients or the right arm of the healthy subjects (Fig 1). The stimulus frequency was 0.5 Hz and the stimulus duration was 0.2 ms. H-reflex and F-wave patterns that resulted

from increased stimulus intensity were divided into 4 types (types 1–4).

**stimulus intensity during muscle relaxation**

no conflicts of interest were declared by the authors.

mal stimulation.

26 Electrodiagnosis in New Frontiers of Clinical Research

patients.

in the CVD patients.

S+:<\$%&?>Stimulating<\$%&?>Electrode<\$%&?>(+),<\$%&?>S−:<\$%&?>Stimulating<\$%&?>Electrode<\$%&?>(−) In<\$%&?>type<\$%&?>1,<\$%&?>the<\$%&?>Fwave<\$%&?>appeared<\$%&?>with<\$%&?>increased<\$%&?>stimulus<\$%&?>intensity,<\$%&?>but<\$%&?>there<\$%&?>was<\$%&? >no<\$%&?>H-reflex<\$%&?>(Fig<\$%&?>2).<\$%&?>The<\$%&?>Fwave<\$%&?>pattern<\$%&?>for<\$%&?>the<\$%&?>upper<\$%&?>arm,<\$%&?>especially<\$%&?>the<\$%&?>distal<\$%&?>portion<\$ %&?>in<\$%&?>healthy<\$%&?>subjects,<\$%&?>roughly<\$%&?>indicated<\$%&?>a<\$%&?>type<\$%&?>1<\$%&?>pattern.<\$%&?>In< In type 1, the F-wave appeared with increased stimulus intensity, but there was no H-reflex (Fig 2). The F-wave pattern for the upper arm, especially the distal portion in healthy subjects, roughly indicated a type 1 pattern. In type 2, the H-reflex and F-wave both appeared with increased stimulus intensity, but the F-wave followed the disappearance of the H-reflex (Fig 3). In type 3, the H-reflex and F-wave both appeared with increased stimulus intensity, but the F-wave appeared during the H-reflex (Fig 4). In type 4, only the H-reflex appeared with increased stimulus intensity; there was no F-wave (Fig 5).

F-wave<\$%&?>appeared<\$%&?>during<\$%&?>the<\$%&?>H-

\$%&?>type<\$%&?>2,<\$%&?>the<\$%&?>H-reflex<\$%&?>and<\$%&?>F-

F-wave<\$%&?>followed<\$%&?>the<\$%&?>disappearance<\$%&?>of<\$%&?>the<\$%&?>H-

reflex<\$%&?>(Fig<\$%&?>4).<\$%&?>In<\$%&?>type<\$%&?>4,<\$%&?>only<\$%&?>the<\$%&?>H-

R+:<\$%&?>Recording<\$%&?>Electrode<\$%&?>(+),<\$%&?>R−:<\$%&?>Recording<\$%&?>Electrode<\$%&?>(−)

reflex<\$%&?>(Fig<\$%&?>3).<\$%&?>In<\$%&?>type<\$%&?>3,<\$%&?>the<\$%&?>H-reflex<\$%&?>and<\$%&?>F-

wave<\$%&?>both<\$%&?>appeared<\$%&?>with<\$%&?>increased<\$%&?>stimulus<\$%&?>intensity,<\$%&?>but<\$%&?>the<\$%&?>

wave<\$%&?>both<\$%&?>appeared<\$%&?>with<\$%&?>increased<\$%&?>stimulus<\$%&?>intensity,<\$%&?>but<\$%&?>the<\$%&?>

reflex<\$%&?>appeared<\$%&?>with<\$%&?>increased<\$%&?>stimulus<\$%&?>intensity;<\$%&?>there<\$%&?>was<\$%&?>no<\$%&?>

**Figure 2.** H-reflex and F-wave patterns resulting from increased stimulus intensity (Type 1) The F-wave appeared with increased stimulus intensity, but there was no H-reflex.

**Figure 4.** H-reflex and F-wave patterns resulting from increased stimulus intensity (Type 3) The H-reflex and F-wave

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29

**Figure 5.** H-reflex and F-wave patterns resulting from increased stimulus intensity (Type 4) Only the H-reflex appeared

with increased stimulus intensity, but there was no F-wave.

both appeared with increased stimulus intensity, but the F-wave appeared during the H-reflex.

**Figure 3.** H-reflex and F-wave patterns resulting from increased stimulus intensity (Type 2) The H-reflex and F-wave both appeared with increased stimulus intensity, but the F-wave followed the disappearance of the H-reflex.

Characteristics of the F-Wave and H-Reflex in Patients with Cerebrovascular Diseases... http://dx.doi.org/10.5772/55887 29

**Figure 4.** H-reflex and F-wave patterns resulting from increased stimulus intensity (Type 3) The H-reflex and F-wave both appeared with increased stimulus intensity, but the F-wave appeared during the H-reflex.

**Figure 2.** H-reflex and F-wave patterns resulting from increased stimulus intensity (Type 1) The F-wave appeared with

**Figure 3.** H-reflex and F-wave patterns resulting from increased stimulus intensity (Type 2) The H-reflex and F-wave both appeared with increased stimulus intensity, but the F-wave followed the disappearance of the H-reflex.

increased stimulus intensity, but there was no H-reflex.

28 Electrodiagnosis in New Frontiers of Clinical Research

**Figure 5.** H-reflex and F-wave patterns resulting from increased stimulus intensity (Type 4) Only the H-reflex appeared with increased stimulus intensity, but there was no F-wave.

Neurological findings, including muscle tonus and tendon reflex, were also evaluated. Findings of muscle tonus and tendon reflex were classified into increased (markedly, moder‐ ately, and slightly), normal, and decreased.

These results indicated that the H-reflex, and not the F-wave, appeared with supramaximal stimulation in patients with a relative increase in excitability of spinal neural function. Furthermore, the neurological signs of muscle tonus and tendon reflex affected H-reflex and F-wave patterns in the CVD patients. These H-reflex and F-wave patterns were therefore used

Characteristics of the F-Wave and H-Reflex in Patients with Cerebrovascular Diseases...

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31

**3. Characteristics of the H-reflex and F-wave in different stretched arm**

Ten hemiplegic patients (4 male and 6 female) with hypertonus caused by CVD were tested. The mean patient age was 53.2 years (range: 34–63 years). There were 5 patients with cerebral hemorrhage (2 with right and 3 with left hemiplegia) and 5 with cerebral infarction (2 with right and 3 with left hemiplegia). The cortical location of the lesion, as verified by brain computed tomography, was temporal in 4 patients, parietal in 2, and temporo-occipital in 2. The lesion was located in the brain stem in the remaining 2 patients. Patients were divided into 3 groups on the basis of the extent of increase in muscle tonus: one group with slightly increased muscle tonus (2 patients), one with moderately increased muscle tonus (6 patients),

The H-reflexes before, during, and 0, 2, 4, 6, 8, and 10 min after continuous stretching of the abductor pollicis brevis (APB) muscle of the affected side were recorded following stimulation of the median nerve at the wrist. The intensity of the constant stimulation current was 1.2 times greater than that of the minimum current required to evoke an M-wave with a stimulus frequency of 0.5 Hz and duration of 0.2 ms. Stimulation was performed 30 times in each trial. The H-reflex was analyzed for persistence, amplitude ratio of H/M, and latency, which was determined as the mean of measurable H-reflexes. Stretching comprised continuous stretching of the affected arm with shoulder joint abduction, elbow joint extension, wrist joint dorsiflex‐ ion, and finger extension for 1 min (Fig 6). Using this data, we analyzed H-reflex characteristics resulting from continuous stretching of the affected arm as well as the relationship between

the effects of continuous stretching and neurological findings in the CVD patients.

Persistence and amplitude ratio of H/M were significantly lower (p < 0.05) after stretching than before stretching; these characteristics gradually recovered after continuous stretching. Figure 7 shows the amplitude ratio of H/M before, during, and after continuous stretching. A typical H-reflex is shown in Figure 8. There was no significant difference in latency. Persistence and amplitude ratio of H/M during continuous stretching were lower than those before and after stretching in the patients with moderately increased muscle tonus. The amplitude ratio of H/ M before, during, and after continuous stretching in patients with moderately increased muscle tonus is shown in Figure 9. On the other hand, H-reflex characteristics were the same before, during, and after continuous stretching in the patients with slightly or markedly increased muscle tonus (Fig 10). Latency was the same before, during, and after continuous stretching in all patients, irrespective of slightly, moderately, or markedly increased muscle

**3.1. The effects of continuous stretching of the affected arm (the H-reflex study)**

for the neurological evaluation of the CVD patients.

and one with markedly increased muscle tonus (2 patients).

**positions in the CVD patients**

tonus.

The results were analyzed in terms of the characteristic appearance of the H-reflex and F-wave in the healthy subjects and the relationship between the neurological findings of CVD and the characteristic appearance of the H-reflex and F-wave in the CVD patients.

H-reflex and F-wave patterns resulting from increased stimulus intensity were type 1 in all healthy subjects. The relationship between H-reflex and F-wave patterns resulting from increased stimulus intensity and the neurological signs of CVD is shown in Tables 1 and 2. Hreflex and F-wave patterns resulting from increased stimulus intensity in patients with markedly increased muscle tonus and tendon reflex were most frequently type 4 patterns, those in patients with moderately increased muscle tonus and tendon reflex were type 2 or 3 patterns, those in patients with slightly increased muscle tonus and tendon reflex were type 1 or 2 patterns, and those in patients with normal or decreased muscle tonus and tendon reflex were type 1 patterns.


The number of subjects was 31 (Type 1: 10, Type 2: 8, Type 3: 7, Type 4: 6)

**Table 1.** The relationship between H-reflex and F-wave patterns resulting from increased stimulus intensity and muscle tonus


The number of subjects was 31(Type 1: 10, Type 2: 8, Type 3: 7, Type 4: 6)

**Table 2.** The relationship between H-reflex and F-wave patterns resulting from increased stimulus intensity and tendon reflex

These results indicated that the H-reflex, and not the F-wave, appeared with supramaximal stimulation in patients with a relative increase in excitability of spinal neural function. Furthermore, the neurological signs of muscle tonus and tendon reflex affected H-reflex and F-wave patterns in the CVD patients. These H-reflex and F-wave patterns were therefore used for the neurological evaluation of the CVD patients.
