Eur. Neurol. 13: 395-404 (1975)
The Palmo-Mental Reflex An Electrophysiological Study
H. D e h en , N. B athien and J. C ambier Clinique Neurologique, Hôpital Beaujon, Clichy, and Laboratoire de Neurophysiologie, Hôpital Saint Antoine, Paris
Key Words. Palmo-mental reflex • Cutaneous reflexes • Polysynaptic reflexes Abstract. Repeated electric stimulation of the ulnar nerve fibers was applied at the wrist in 7 normal and 32 pathological subjects; the response reflexes were simul taneously recorded in the chin muscles and at the upper limb, on the flexor carpi ulnaris. Although it is possible to obtain two distinct polysynaptic reflexes by cuta neous stimulation of the limb, the palmo-mental reflex causes a unique response, the latency of which may diminish to 35 msec. This response occurs most often at the threshold which elicits a nociceptive reflex of the upper limb. The palmo-mental reflex is almost always bilateral for a unilateral stimulation and in numerous inst ances is characterized by a wide receptive field. These findings suggest that the palmo-mental reflex is an early event in a general nociceptive response. In the normal subject this fragment of a general response to a painful stimulus is highly sup pressed as are the local reflexes by suprasegmental control. The palmo-mental reflex is liberated and augmented in the event of habitually bilateral lesions of the pyra midal tract or the extra-pyramidal formations.
Received: January 10, 1975; accepted: January 28, 1975.
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The use of the reflex described by M arinesco and R adovici [22] in 1920 as a diagnostic sign of brain dysfunction has been limited by its oc currence in normal subjects. The frequence of confirmation in the normal subject varied from 0 to 50% [3, 19, 20, 22, 24] (table I). In addition, most of these authors recognize that the reflex is effectively constant dur ing the first months of life [13, 21]. Thus we are dealing with an archaic reflex which occasionally persists in the adult. The pathological processes responsible for the reappearance or the exaggeration of this archaic reflex are usually bilateral: lacunar infarct, lateral amyotrophic sclerosis,
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Table I. Frequence of the palmo-mental reflex in the normal subject Authors and year
Frequence, % adults
M arinesco and Radovici [22], 1920 H erscovici [13], 1920 Sarno [24], 1926 M agnusson and W ernstedt [21], 1935 T hompson [27], 1945 Blake and K unkle [3], 1951 M cL aughlin and H aines [20], 1953 M c Donald et al. [19], 1963
50 8 0 2-3 49 3 30
infants < 1 year 74 75-90 73
atrophic dementiae, frontal tumors, multiple sclerosis, Parkinson’s disease ... They can be sometimes unilateral. In 1956, Bracha [4, 5] described a new research technique using the stimulation of the internal face of the thumb and proposed the term ‘pollicomental reflex’. This method would never produce a response in the normal subject. In the majority of cases, the pollicomental reflex would indicate, although not exclusively, a lesion of the contralateral premotor cortex. Very few electrophysiological studies have been consecrated to the palmo-mental reflex and very little is known about the organization and the significance of this reflex. However, in 1961 R eis [23] consistently evoked a response reflex in the normal subject when the stimulation was sufficiently intense. We have recorded the palmo-mental reflex in normal subjects and then in various pathological circumstances. We shall interpret our findings in the light of recent information concerning the cutaneous polysynaptic reflexes in the limbs [7, 8,14, 25].
Repeated electric stimulation (20-msec duration train of 1-msec square wave pulses at 500 cps) of the ulnar nerve fibers was applied at the wrist with hypodermic electrodes. In some cases, other areas of the skin were stimulated, the intensity of the stimulus varying from 2 to 8 mA. The reflex responses were simultaneously re corded bilaterally (oscilloscope Tektronix 502A), using Bronk needles in the muscles of the chin (PM) and in a bipolar fashion with surface electrodes on flexor carpi ulnaris (FCU).
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Materials and Methods
The Palmo-Mental Reflex
397
Table II. Materials Palmo-mental reflex clinically absent
Palmo-mental reflex clinically present number of cases
Normal subjects 7 Pathological subjects 13 Middle cerebral artery occlusion 3 Parkinson’s disease 1 Lateral amyotrophic sclerosis 2
number of cases Pathological subjects
lacunar infarct lateral amyotrophic sclerosis frontal lesions bilateral unilateral middle cerebral artery occlusion Parkinson’s disease
2 Syringomyelia Wallenberg’s disease 2 Peduncular lesions 1 Protuberantial lesions 1 Cervical spinal cord lesions 1
19
7 4 3 1 2 2
39 recordings were made using this technique with both normal and pathological subjects (table II). However, since we did not have the opportunity to examine one normal subject with a palmo-mental reflex, our positive results concern only pathol ogical subjects.
Results
Nature of the Stimulation The quality of the stimulation inducing the palmo-mental reflex (PM) is defined in relation to the simultaneously recorded polysynaptic reflexes of cutaneous origin in the FCU. Figure 2 shows that for a threshold of
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Characteristics of the Response Figure 1 shows the responses evoked in the homolateral chin muscles by stimulation at increasing levels. The reflex activity is polyphasic. Its amplitude, latency and duration are the direct function of the intensity of the stimulation. For an intensity of 4 mA, the mean latency is 50 msec, the duration of the response then being approximately 90 msec. This re flex activity is commonly bilateral for a unilateral stimulation, the evoked activity having a higher amplitude on the side to which the stimulation was applied.
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20 msec
Fig. 1. Variations in the latency and duration of the palmo-mental reflex during repeated electrical stimulation of the homolateral ulnar nerve at the wrist (20-msec duration trains of 1-msec square ware pulses at 500 cps) of increasing intensity (from I, to I3). At I, (4 mA) the latency of the réponse is 50 msec; at I3 (8 mA) the latency is 35 msec.
Receptive Field When a palmo-mental reflex was recorded it was generally possible to obtain an analogous response from the stimulation of different areas. Fig ure 3 shows that repeated electrical stimulation, applied to the wrist, the throat, the supraorbital region or the abdominal wall, elicits a response reflex of the chin muscles. Stimulation of the fibers of the ulnar (or medi an) nerve, however, has the lowest threshold and yields the most ample results.
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stimulation eliciting the polysynaptic reflex of short latency in the FCU (called R2 in comparison to the R, monosynaptic reflex), the palmo-men tal reflex is absent. This reflex is elicited only when the stimulus is suffi ciently intense to cause a polysynaptic response of long latency (R3). This late response corresponds to a nociceptive reflex, the recording of this ac tivity coincided with the appearance of pain. The palmo-mental reflex corresponds, therefore, to an exteroceptive nociceptive reflex. The thresh old stimulus required to elicit the reflex response is influenced by pathol ogical circumstances; lesions of the corticospinal tract significantly lower the threshold as they induce the nociceptive reflexes of the limbs.
The Palmo-Mental Reflex
399
20 msec
Fig. 2. Elicitation of the palmo-mental reflex by homolateral ulnar nerve stimu lation after increasing the stimulus intensity successively to 2 mA (A), 4 mA (B) and 6 mA (C). Upper tracings: cutaneous polysynaptic reflexes at short latency (R2) and long latency (Rs) of the flexor carpi ulnaris (FCU). Lower tracings: palmo-mental reflex (PM). The PM is elicited when the stimulation is sufficiently intense (4 mA) to evoke a long latency polysynaptic response of FCU.
Inconsistency of the Response Reflex Reis [23], using a similar technique, studied 28 normal subjects and constantly obtained the response reflex; our results are different. We did not obtain a response by electrical stimulation in subjects who did not
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Habituation Repeated stimulation of constant frequence and intensity causes a cu mulative depression, sometimes a total extinction of the response reflex. This general characteristic of polysynaptic reflexes of cutaneous origin [14, 18] is particularly observable for the palmo-mental reflex (fig. 4). This habituation is more rapid than that of the local polysynaptic respon ses. This adaptation of the reflexogenic threshold is diminished under some pathological circumstances, for instance, with bilateral lesions of the pyramidal tract.
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Fig. 3. Receptive areas. Registration of the palmo-mental reflex evoked by re peated electrical stimulation practiced successively in the supraorbital region, at the throat, the wrist, on the abdominal wall. The response to the ulnar (or median) sti mulus shows the highest amplitude.
have the clinical manifestations of the palmo-mental reflex. In that case, for a threshold of stimulation sufficient to evoke a nociceptive reflex in the upper limb, no activity was recorded in the chin muscles. The palmo mental reflex is thus inconsistent. It should be noted, however, that we never utilized a stimulus of intensity greater than 8 mA, since in our esti mation this seems to be the limit tolerable by the superior extremity. The registrations of Reis corresponded to stimuli attaining sometimes 20 mA.
(a) It is established that the palmo-mental reflex is of cutaneous origin. It has been demonstrated that this activity disappears with anesthesia of the receptive field [3]. The qualification of the exteroceptive reflex is in-
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Discussion
The Palmo-Mental Reflex
401
FCU A
PM
FCU B PM
FCU
c PM
20 msec
sufficient. Recent electrophysiological work has shown that it is possible to sustain two distinct reflex activities with a stimulation of cutaneous ori gin in lower limb [14, 25) as in upper limb [6, 8). These two reflex activi ties correspond to different types of stimulation. The initial response (or at short latency, R2) is evoked by a non-painful tactile stimulus, the late response (or at long latency, R:i) appeared to be a nociceptive reflex; the recording of this activity coincided with the appearance of a pain sensa tion. The threshold and the reciprocal organization of these two type of responses are modified in pathological circumstances. Thus, in spasticity [2,9,17] there were found a facilitation of polysynaptic reflex responses of nociceptive origin, a poor adaptation of the reflex threshold, and a degra dation of the specific properties of the stimulation. Non-nociceptive res ponses, on the other hand, are difficult to elicit [7, 26). The palmo-mental reflex gives rise to a unique response. This response appears most often for the threshold evoking a long latency response of the FCU. The palmo mental reflex is, therefore, an exteroceptive nociceptive response.
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Fig. 4. Habituation of the palmo-mental reflex during stimulation at constant frequence and intensity (4 mA). Upper tracings: polysynaptic reflexes at short laten cy (R2) and long latency (R3) of the FCU. Lower tracings: cumulative depression of the palmo-mental reflex (PM).
D ehen /B athien /C ambier
(b) It has been shown [10-12, 16] that the cutaneous nociceptive re flex does not consist of a rough flexion unalterable by the place of stimu lation. The reflex response is organized in such a way that a protective withdrawal occurs according to the localization of the stimulus. The palmo-mental reflex, a nociceptive reflex, is not bound by this notion of ‘lo cal sign' (S herrington ). It is thus possible to obtain this reflex, notably under pathological circumstances, by the stimulation of multiple areas; the thenar eminence, however, has the lowest reflexogenic threshold. (c) The organization of the reflex circuit is hypothetical. Certain ob servers [5, 15] contend that the reflex arc involves the cerebral cortex. According to this theory, the stimulus is transmitted by rapid conduction fibers to the sensitive cortex and then to the motor cortex at the level of the representation of the face. The response reflex would be noted only in the event of a lesion of the premotor cortex which normally inhibits the activity of the motor cortex. Others [3, 23] maintain that the reflex is purely intersegmentary. For R eis [23], the fact that the response of the chin muscles may be elicited by stimuli carried from areas at a distance from the habitual reflexogenic zone, weakens the case for the theory of a long circuit involving the cortex, the bases of this theory being the conti guity of the face-chin-thumb representations at the level of the motor cortex. Whatever the organization of the reflex circuit, it should be noted that the pathological palmo-mental reflex is observed in the event of lesions involving the pyramidal tract (lateral amyotrophic sclerosis) as well as the extra-pyramidal formations (Parkinson’s disease). Thus it is possible to conclude that the supra-segmentary formations exercise a per manent inhibiting control, involving certainly the geniculate tract and, perhaps, the reticular formation of the brain stem. (d) The significance of the palmo-mental reflex is still obscure. The method of triggering and the organization of the response suggest that it forms a part of a global nociceptive response. The face muscles play an important role in the expression of discomfort [3, 27]. It has been shown experimentally that the mobilization of the face muscles signals a state of alert (reaction to fear, shame or rage). The nociceptive stimulation of a limb may thus give rise to two distinct responses [23]: a local protective response whose functional organization is oriented to appropriately with draw the body surface adjacent to the stimulus; a global response mobiliz ing the entire organism (to flight or fight in C annon ’s terms). The palmo-mental reflex is an early event in a generalized nociceptive reflex. In the normal subject, this fragment of the general response to a
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402
The Palmo-Mental Reflex
403
painful stimulus is more highly suppressed than are the local reflexes by the supra-segmentary structures. The palmo-mental response is liberated and augmented with bilateral lesions of the corticospinal tract (which has a well-known effect on local responses [2, 7, 17]) or disorders effecting the extra-pyramidal system.
Rejerences 1 A brahams, V. C.; H ilton , S. M., and M alcom, J. L.: Sensory input to hypothal amus and mesencephalitic region subserving the defense reaction. J. Physiol., Lond. 149: 45-59 (1959). 2 Bathien , N. and Bourdarias, H.: Lower limb cutaneous reflexes in hemiplegia. Brain 95: 447-456 (1972). 3 Blake, J. R. and Kunkle, E. G.: The palmo-mental reflex: a physiological and clinical analysis. Archs Neurol. Psychiat., Lond. 65: 337-345 (1951). 4 Bracha, S.: Le réflexe pollico-mentonnier (une modification du réflexe palmomentonnier). Revue neurol. 95: 429-430 (1956). 5 Bracha, S.: The clinical value of the pollico-mental reflex in neuropathology. J. nerv. ment. Dis. 127: 91-94 (1958). 6 C ambier, J.; D ehen , H. et Bathien , N.: La préhension pathologique: son étude par l'enregistrement des réflexes polysynaptiques du membre supérieur. Revue neurol. 126: 17-29 (1972). 7 C ambier,, J.; Dehen, H., and Bathien , N.: Upper limb cutaneous polysynaptic reflexes. J. neurol. Sci. 22: 39-49 (1974). 8 D ehen , H. et Bathien , N.: Les réflexes polysynaptiques du membre supérieur chez l'homme normal. Presse méd. 79: 1898-1900 (1971). 9 G rimby, L.: Pathological plantar response: disturbance of the normal integration of flexor and extensor reflex components. J. Neurol. Neurosurg. Psychiat. 26: 314-322 (1963). 10 H agbarth, K. E.: Excitatory and inhibitory skin areas flexor and extensor reflex components. Acta physiol, scand. 26: suppl. 94, pp. 1-58 (1952). 11 H agbarth, K. E. and K ugelberg , E.: Plasticity of the human abdominal skin re flex. Brain 81: 290-304 (1958). 12 K agbarth, K. E.: Spinal withdrawal reflexes in the human lower limbs. J. Neu rol. Neurosurg. Psychiat. 23: 222-227 (1960). 13 H erscovici, H.: Le réflexe palmo-mentonnier chez le nouveau né. Spitalul (1920). (Cited by A. R adovici.)
15 Kanigowski, Z.: Localisation of the palm-chin reflex and its behavior in some disturbances of consciousness. Proc. 1st Int. Congr. Neurol. Sci., Brussels 1957. 16 K ugelberg , E. and H agbarth, K. E.: Spinal mechanism of the abdominal and erector spinae reflexes. Brain 81: 290-304 (1958). 17 K ugelberg , E.; E klund , K., and G rimby, L.: An electromyographic study of
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14 H ugon, M.: Réflexes polysynaptique cutanés et commandes volontaires; 232 pp.; thèse Sciences, Paris (1967).
404
19
20 21 22 23 24 25 26 27
the nociceptive reflexes of the lower limb: mechanisms of the plantar response. Brain 83: 394-410 (1960). K ugelberg , E.: Polysynaptic reflexes of clinical importance. Electroenceph. clin. Neurophysiol., suppl. 22, pp. 103-111 (1962). Mc D onai.d , J. K.; K eli.ey, J. J.; Brock, L. D., and Bartunek, E. J.: The varia bility of the palmo-mental reflex. J. nerv. ment. Dis. 136: 207-215 (1963). M c L aughlin , J. J. and H aines, W. M.: A clinical report on the palm-chin re flex. Dis. nerv. Syst. 14: 378-380 (1953). M agnusson, J. M. and W ernstedt , W.: The infantile palmo-mentalis reflex. Acta paediat., Stockh. 17: suppl. 1, pp. 241-245 (1935). M arinesco, G. et R adovici, A.: Sur un réflexe cutané nouveau: le réflexe palmo-mentonnier. Revue neurol. 27: 237-240 (1920). R eis , D. L: The palmo-mental reflex: a physiological study in normal man. Arch, neurol., Chicago 4: 486-498 (1961). Sarno, D.: Sul riflesso palmo-mentonniero. Neurologica 3: 326-332 (1926). Shahani, B. and Young , R. R.: Normal human flexor reflexes. Electroenceph. clin. Neurophysiol. 27: 725-732 (1969). Shahani, B. and Young , R. R.: Human flexor reflexes. J. Neurol. Neurosurg. Psychiat. 34: 616-627 (1971). T hompson , G. W.: The palmo-mental sign. Bull. Los Ang. neurol. Soc. 10: 174-175 (1945).
Dr. H. D ehen , Chef de Clinique Neurologique, Hôpital Beaujon, 100, Boulevard du Général-Leclerc, F-92 110 Clichy (France)
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18
D ehen /B athien/C ambifr
The Palmo-Mental Reflex An Electrophysiological Study
H. D e h en , N. B athien and J. C ambier Clinique Neurologique, Hôpital Beaujon, Clichy, and Laboratoire de Neurophysiologie, Hôpital Saint Antoine, Paris
Key Words. Palmo-mental reflex • Cutaneous reflexes • Polysynaptic reflexes Abstract. Repeated electric stimulation of the ulnar nerve fibers was applied at the wrist in 7 normal and 32 pathological subjects; the response reflexes were simul taneously recorded in the chin muscles and at the upper limb, on the flexor carpi ulnaris. Although it is possible to obtain two distinct polysynaptic reflexes by cuta neous stimulation of the limb, the palmo-mental reflex causes a unique response, the latency of which may diminish to 35 msec. This response occurs most often at the threshold which elicits a nociceptive reflex of the upper limb. The palmo-mental reflex is almost always bilateral for a unilateral stimulation and in numerous inst ances is characterized by a wide receptive field. These findings suggest that the palmo-mental reflex is an early event in a general nociceptive response. In the normal subject this fragment of a general response to a painful stimulus is highly sup pressed as are the local reflexes by suprasegmental control. The palmo-mental reflex is liberated and augmented in the event of habitually bilateral lesions of the pyra midal tract or the extra-pyramidal formations.
Received: January 10, 1975; accepted: January 28, 1975.
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The use of the reflex described by M arinesco and R adovici [22] in 1920 as a diagnostic sign of brain dysfunction has been limited by its oc currence in normal subjects. The frequence of confirmation in the normal subject varied from 0 to 50% [3, 19, 20, 22, 24] (table I). In addition, most of these authors recognize that the reflex is effectively constant dur ing the first months of life [13, 21]. Thus we are dealing with an archaic reflex which occasionally persists in the adult. The pathological processes responsible for the reappearance or the exaggeration of this archaic reflex are usually bilateral: lacunar infarct, lateral amyotrophic sclerosis,
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D ehen /B athien /C ambier
Table I. Frequence of the palmo-mental reflex in the normal subject Authors and year
Frequence, % adults
M arinesco and Radovici [22], 1920 H erscovici [13], 1920 Sarno [24], 1926 M agnusson and W ernstedt [21], 1935 T hompson [27], 1945 Blake and K unkle [3], 1951 M cL aughlin and H aines [20], 1953 M c Donald et al. [19], 1963
50 8 0 2-3 49 3 30
infants < 1 year 74 75-90 73
atrophic dementiae, frontal tumors, multiple sclerosis, Parkinson’s disease ... They can be sometimes unilateral. In 1956, Bracha [4, 5] described a new research technique using the stimulation of the internal face of the thumb and proposed the term ‘pollicomental reflex’. This method would never produce a response in the normal subject. In the majority of cases, the pollicomental reflex would indicate, although not exclusively, a lesion of the contralateral premotor cortex. Very few electrophysiological studies have been consecrated to the palmo-mental reflex and very little is known about the organization and the significance of this reflex. However, in 1961 R eis [23] consistently evoked a response reflex in the normal subject when the stimulation was sufficiently intense. We have recorded the palmo-mental reflex in normal subjects and then in various pathological circumstances. We shall interpret our findings in the light of recent information concerning the cutaneous polysynaptic reflexes in the limbs [7, 8,14, 25].
Repeated electric stimulation (20-msec duration train of 1-msec square wave pulses at 500 cps) of the ulnar nerve fibers was applied at the wrist with hypodermic electrodes. In some cases, other areas of the skin were stimulated, the intensity of the stimulus varying from 2 to 8 mA. The reflex responses were simultaneously re corded bilaterally (oscilloscope Tektronix 502A), using Bronk needles in the muscles of the chin (PM) and in a bipolar fashion with surface electrodes on flexor carpi ulnaris (FCU).
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Materials and Methods
The Palmo-Mental Reflex
397
Table II. Materials Palmo-mental reflex clinically absent
Palmo-mental reflex clinically present number of cases
Normal subjects 7 Pathological subjects 13 Middle cerebral artery occlusion 3 Parkinson’s disease 1 Lateral amyotrophic sclerosis 2
number of cases Pathological subjects
lacunar infarct lateral amyotrophic sclerosis frontal lesions bilateral unilateral middle cerebral artery occlusion Parkinson’s disease
2 Syringomyelia Wallenberg’s disease 2 Peduncular lesions 1 Protuberantial lesions 1 Cervical spinal cord lesions 1
19
7 4 3 1 2 2
39 recordings were made using this technique with both normal and pathological subjects (table II). However, since we did not have the opportunity to examine one normal subject with a palmo-mental reflex, our positive results concern only pathol ogical subjects.
Results
Nature of the Stimulation The quality of the stimulation inducing the palmo-mental reflex (PM) is defined in relation to the simultaneously recorded polysynaptic reflexes of cutaneous origin in the FCU. Figure 2 shows that for a threshold of
Downloaded by: Univ. of California Santa Barbara 128.111.121.42 - 9/21/2018 12:31:53 PM
Characteristics of the Response Figure 1 shows the responses evoked in the homolateral chin muscles by stimulation at increasing levels. The reflex activity is polyphasic. Its amplitude, latency and duration are the direct function of the intensity of the stimulation. For an intensity of 4 mA, the mean latency is 50 msec, the duration of the response then being approximately 90 msec. This re flex activity is commonly bilateral for a unilateral stimulation, the evoked activity having a higher amplitude on the side to which the stimulation was applied.
398
D ehen /B atheen/C ambier
20 msec
Fig. 1. Variations in the latency and duration of the palmo-mental reflex during repeated electrical stimulation of the homolateral ulnar nerve at the wrist (20-msec duration trains of 1-msec square ware pulses at 500 cps) of increasing intensity (from I, to I3). At I, (4 mA) the latency of the réponse is 50 msec; at I3 (8 mA) the latency is 35 msec.
Receptive Field When a palmo-mental reflex was recorded it was generally possible to obtain an analogous response from the stimulation of different areas. Fig ure 3 shows that repeated electrical stimulation, applied to the wrist, the throat, the supraorbital region or the abdominal wall, elicits a response reflex of the chin muscles. Stimulation of the fibers of the ulnar (or medi an) nerve, however, has the lowest threshold and yields the most ample results.
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stimulation eliciting the polysynaptic reflex of short latency in the FCU (called R2 in comparison to the R, monosynaptic reflex), the palmo-men tal reflex is absent. This reflex is elicited only when the stimulus is suffi ciently intense to cause a polysynaptic response of long latency (R3). This late response corresponds to a nociceptive reflex, the recording of this ac tivity coincided with the appearance of pain. The palmo-mental reflex corresponds, therefore, to an exteroceptive nociceptive reflex. The thresh old stimulus required to elicit the reflex response is influenced by pathol ogical circumstances; lesions of the corticospinal tract significantly lower the threshold as they induce the nociceptive reflexes of the limbs.
The Palmo-Mental Reflex
399
20 msec
Fig. 2. Elicitation of the palmo-mental reflex by homolateral ulnar nerve stimu lation after increasing the stimulus intensity successively to 2 mA (A), 4 mA (B) and 6 mA (C). Upper tracings: cutaneous polysynaptic reflexes at short latency (R2) and long latency (Rs) of the flexor carpi ulnaris (FCU). Lower tracings: palmo-mental reflex (PM). The PM is elicited when the stimulation is sufficiently intense (4 mA) to evoke a long latency polysynaptic response of FCU.
Inconsistency of the Response Reflex Reis [23], using a similar technique, studied 28 normal subjects and constantly obtained the response reflex; our results are different. We did not obtain a response by electrical stimulation in subjects who did not
Downloaded by: Univ. of California Santa Barbara 128.111.121.42 - 9/21/2018 12:31:53 PM
Habituation Repeated stimulation of constant frequence and intensity causes a cu mulative depression, sometimes a total extinction of the response reflex. This general characteristic of polysynaptic reflexes of cutaneous origin [14, 18] is particularly observable for the palmo-mental reflex (fig. 4). This habituation is more rapid than that of the local polysynaptic respon ses. This adaptation of the reflexogenic threshold is diminished under some pathological circumstances, for instance, with bilateral lesions of the pyramidal tract.
400
D ehen /B athien /C ambier
Fig. 3. Receptive areas. Registration of the palmo-mental reflex evoked by re peated electrical stimulation practiced successively in the supraorbital region, at the throat, the wrist, on the abdominal wall. The response to the ulnar (or median) sti mulus shows the highest amplitude.
have the clinical manifestations of the palmo-mental reflex. In that case, for a threshold of stimulation sufficient to evoke a nociceptive reflex in the upper limb, no activity was recorded in the chin muscles. The palmo mental reflex is thus inconsistent. It should be noted, however, that we never utilized a stimulus of intensity greater than 8 mA, since in our esti mation this seems to be the limit tolerable by the superior extremity. The registrations of Reis corresponded to stimuli attaining sometimes 20 mA.
(a) It is established that the palmo-mental reflex is of cutaneous origin. It has been demonstrated that this activity disappears with anesthesia of the receptive field [3]. The qualification of the exteroceptive reflex is in-
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Discussion
The Palmo-Mental Reflex
401
FCU A
PM
FCU B PM
FCU
c PM
20 msec
sufficient. Recent electrophysiological work has shown that it is possible to sustain two distinct reflex activities with a stimulation of cutaneous ori gin in lower limb [14, 25) as in upper limb [6, 8). These two reflex activi ties correspond to different types of stimulation. The initial response (or at short latency, R2) is evoked by a non-painful tactile stimulus, the late response (or at long latency, R:i) appeared to be a nociceptive reflex; the recording of this activity coincided with the appearance of a pain sensa tion. The threshold and the reciprocal organization of these two type of responses are modified in pathological circumstances. Thus, in spasticity [2,9,17] there were found a facilitation of polysynaptic reflex responses of nociceptive origin, a poor adaptation of the reflex threshold, and a degra dation of the specific properties of the stimulation. Non-nociceptive res ponses, on the other hand, are difficult to elicit [7, 26). The palmo-mental reflex gives rise to a unique response. This response appears most often for the threshold evoking a long latency response of the FCU. The palmo mental reflex is, therefore, an exteroceptive nociceptive response.
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Fig. 4. Habituation of the palmo-mental reflex during stimulation at constant frequence and intensity (4 mA). Upper tracings: polysynaptic reflexes at short laten cy (R2) and long latency (R3) of the FCU. Lower tracings: cumulative depression of the palmo-mental reflex (PM).
D ehen /B athien /C ambier
(b) It has been shown [10-12, 16] that the cutaneous nociceptive re flex does not consist of a rough flexion unalterable by the place of stimu lation. The reflex response is organized in such a way that a protective withdrawal occurs according to the localization of the stimulus. The palmo-mental reflex, a nociceptive reflex, is not bound by this notion of ‘lo cal sign' (S herrington ). It is thus possible to obtain this reflex, notably under pathological circumstances, by the stimulation of multiple areas; the thenar eminence, however, has the lowest reflexogenic threshold. (c) The organization of the reflex circuit is hypothetical. Certain ob servers [5, 15] contend that the reflex arc involves the cerebral cortex. According to this theory, the stimulus is transmitted by rapid conduction fibers to the sensitive cortex and then to the motor cortex at the level of the representation of the face. The response reflex would be noted only in the event of a lesion of the premotor cortex which normally inhibits the activity of the motor cortex. Others [3, 23] maintain that the reflex is purely intersegmentary. For R eis [23], the fact that the response of the chin muscles may be elicited by stimuli carried from areas at a distance from the habitual reflexogenic zone, weakens the case for the theory of a long circuit involving the cortex, the bases of this theory being the conti guity of the face-chin-thumb representations at the level of the motor cortex. Whatever the organization of the reflex circuit, it should be noted that the pathological palmo-mental reflex is observed in the event of lesions involving the pyramidal tract (lateral amyotrophic sclerosis) as well as the extra-pyramidal formations (Parkinson’s disease). Thus it is possible to conclude that the supra-segmentary formations exercise a per manent inhibiting control, involving certainly the geniculate tract and, perhaps, the reticular formation of the brain stem. (d) The significance of the palmo-mental reflex is still obscure. The method of triggering and the organization of the response suggest that it forms a part of a global nociceptive response. The face muscles play an important role in the expression of discomfort [3, 27]. It has been shown experimentally that the mobilization of the face muscles signals a state of alert (reaction to fear, shame or rage). The nociceptive stimulation of a limb may thus give rise to two distinct responses [23]: a local protective response whose functional organization is oriented to appropriately with draw the body surface adjacent to the stimulus; a global response mobiliz ing the entire organism (to flight or fight in C annon ’s terms). The palmo-mental reflex is an early event in a generalized nociceptive reflex. In the normal subject, this fragment of the general response to a
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painful stimulus is more highly suppressed than are the local reflexes by the supra-segmentary structures. The palmo-mental response is liberated and augmented with bilateral lesions of the corticospinal tract (which has a well-known effect on local responses [2, 7, 17]) or disorders effecting the extra-pyramidal system.
Rejerences 1 A brahams, V. C.; H ilton , S. M., and M alcom, J. L.: Sensory input to hypothal amus and mesencephalitic region subserving the defense reaction. J. Physiol., Lond. 149: 45-59 (1959). 2 Bathien , N. and Bourdarias, H.: Lower limb cutaneous reflexes in hemiplegia. Brain 95: 447-456 (1972). 3 Blake, J. R. and Kunkle, E. G.: The palmo-mental reflex: a physiological and clinical analysis. Archs Neurol. Psychiat., Lond. 65: 337-345 (1951). 4 Bracha, S.: Le réflexe pollico-mentonnier (une modification du réflexe palmomentonnier). Revue neurol. 95: 429-430 (1956). 5 Bracha, S.: The clinical value of the pollico-mental reflex in neuropathology. J. nerv. ment. Dis. 127: 91-94 (1958). 6 C ambier, J.; D ehen , H. et Bathien , N.: La préhension pathologique: son étude par l'enregistrement des réflexes polysynaptiques du membre supérieur. Revue neurol. 126: 17-29 (1972). 7 C ambier,, J.; Dehen, H., and Bathien , N.: Upper limb cutaneous polysynaptic reflexes. J. neurol. Sci. 22: 39-49 (1974). 8 D ehen , H. et Bathien , N.: Les réflexes polysynaptiques du membre supérieur chez l'homme normal. Presse méd. 79: 1898-1900 (1971). 9 G rimby, L.: Pathological plantar response: disturbance of the normal integration of flexor and extensor reflex components. J. Neurol. Neurosurg. Psychiat. 26: 314-322 (1963). 10 H agbarth, K. E.: Excitatory and inhibitory skin areas flexor and extensor reflex components. Acta physiol, scand. 26: suppl. 94, pp. 1-58 (1952). 11 H agbarth, K. E. and K ugelberg , E.: Plasticity of the human abdominal skin re flex. Brain 81: 290-304 (1958). 12 K agbarth, K. E.: Spinal withdrawal reflexes in the human lower limbs. J. Neu rol. Neurosurg. Psychiat. 23: 222-227 (1960). 13 H erscovici, H.: Le réflexe palmo-mentonnier chez le nouveau né. Spitalul (1920). (Cited by A. R adovici.)
15 Kanigowski, Z.: Localisation of the palm-chin reflex and its behavior in some disturbances of consciousness. Proc. 1st Int. Congr. Neurol. Sci., Brussels 1957. 16 K ugelberg , E. and H agbarth, K. E.: Spinal mechanism of the abdominal and erector spinae reflexes. Brain 81: 290-304 (1958). 17 K ugelberg , E.; E klund , K., and G rimby, L.: An electromyographic study of
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14 H ugon, M.: Réflexes polysynaptique cutanés et commandes volontaires; 232 pp.; thèse Sciences, Paris (1967).
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the nociceptive reflexes of the lower limb: mechanisms of the plantar response. Brain 83: 394-410 (1960). K ugelberg , E.: Polysynaptic reflexes of clinical importance. Electroenceph. clin. Neurophysiol., suppl. 22, pp. 103-111 (1962). Mc D onai.d , J. K.; K eli.ey, J. J.; Brock, L. D., and Bartunek, E. J.: The varia bility of the palmo-mental reflex. J. nerv. ment. Dis. 136: 207-215 (1963). M c L aughlin , J. J. and H aines, W. M.: A clinical report on the palm-chin re flex. Dis. nerv. Syst. 14: 378-380 (1953). M agnusson, J. M. and W ernstedt , W.: The infantile palmo-mentalis reflex. Acta paediat., Stockh. 17: suppl. 1, pp. 241-245 (1935). M arinesco, G. et R adovici, A.: Sur un réflexe cutané nouveau: le réflexe palmo-mentonnier. Revue neurol. 27: 237-240 (1920). R eis , D. L: The palmo-mental reflex: a physiological study in normal man. Arch, neurol., Chicago 4: 486-498 (1961). Sarno, D.: Sul riflesso palmo-mentonniero. Neurologica 3: 326-332 (1926). Shahani, B. and Young , R. R.: Normal human flexor reflexes. Electroenceph. clin. Neurophysiol. 27: 725-732 (1969). Shahani, B. and Young , R. R.: Human flexor reflexes. J. Neurol. Neurosurg. Psychiat. 34: 616-627 (1971). T hompson , G. W.: The palmo-mental sign. Bull. Los Ang. neurol. Soc. 10: 174-175 (1945).
Dr. H. D ehen , Chef de Clinique Neurologique, Hôpital Beaujon, 100, Boulevard du Général-Leclerc, F-92 110 Clichy (France)
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