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Biomedical subjects

H Dehen

Publications and source records attributed to H Dehen.

At least 55 records · Page 3Linked to original sources
PubMed1977

Respective importance of different electrophysiological parameters in alcoholic neuropathy.

An electrophysiological study of alcoholic and normal subjects is presented. The aim was to evaluate the respective importance of the various parameters. The subjects were divided into 4 groups: (I) normal subjects; (II) chronic alcoholics without clinical evidence of neuropathy; (III) chronic alcoholics with sensory symptoms; (IV) chronic alcoholics with both motor and sensory symptoms. The electrophysiological parameters tested were: conduction velocity (CV) in Ia sensory fibres, motor fibres, and cutaneous sensory fibres of the popliteal nerve, CV in the sural nerve, amplitude of the cutaneous sensory action potentials (SAP) in the sural and popliteal nerves, H reflex and M response of the soleus muscle, and electromyograms from the extensor digitorum brevis muscle. In the 3 groups of alcoholics, the electrophysiological findings were more abnormal than the clinical symptoms could have predicted. The more sensitive parameters were: (1) CV in the Ia sensory fibres of the popliteal nerve, which is slowed very early (in Group II) and (2) measurement of the amplitude of sural and popliteal SAP's which are also reduced early (in Group II). The nature of the mechanisms involved are discussed.

Action Potentials↗
PubMed1977

Imitation synkinesia and sensory control of movement.

Immitation synkinesia is usually associated with thalamic or parietal lesions. Analysis of three cases shows that the lesions may affect the posterior columns of the spinal cord or even the peripheral nervous system. In our cases, two facts stand out, a large measure of integrity of motor activity and predominant disturbances of lemniscal sensation. Imitation synkinesia should therefore not be seen as due to a lesion of a particular structure but to the disorganization of the lemniscal system at any level. Functional interconnection between the lemniscal and motor systems occurs only in the cerebral cortex. In the light of this fact, imitation synkinesia can be interpreted as the loss of particular functions in the principal cortical motor neurons.

Female↗
PubMed1976

Blink reflex in hemiplegia.

An electrophysiological study of the blink reflex was undertaken in 20 normal subjects and in 28 patients complaining of central facial palsy caused by unilateral hemispheral damage. In normal subjects, the latency, amplitude and organization of R1 and R2 responses are well known. Habituation of R2 responses occurred between 1 and 2 c/sec stimulation rate. R1 responses habituated at a higher stimulation rate (5 c/sec). In patients with unilateral hemispheral lesion, our results showed that changes in the blink reflex responses were bilateral. On the hemiplegic side the responses showed a decreased amplitude, while they were facilitated on the "normal" side. However, there was no change in latency of the two components of the reflex, on both sides. On the other hand, habituation of the late component occurred on the hemiplegic side for low stimulation rates: (0.5--1 c/sec), while on the "normal" side there was less habituation (3--4 c/sec), as compared with normal subjects. These results agree with those of experimental studies on cortical modulatory influences on brain-stem nuclei. They suggest a tactile origin of the two components of the blink reflex.

Adult↗
PubMed1976

[H-reflex in the extensor digitorum brevis muscle: study in the normal subject and in latent alcoholic neuropathies].

A comparative electromyographic study was carried out in normal subjects (group I) and in alcoholics without clinical evidence of polyneuropathy (group II). -The H reflex of the extensor digitorum brevis muscle (E.D.B.), the electromyogram of EDB, the conduction velocity of the fasted motor fibers of the peroneal nerve (PN), the sensory conduction velocity and amplitude of the evoked potential of the cutaneous fibers of PN, the H reflex of the soleus muscle. -Two kinds of changes were observed in group II: --a significant increase in the latent period of H respones in EDB, in particular the latent period of responses provoked by distal stimulation of PN (+25 PER CENT); --A SIGNIFICANT DECREASE IN THE AMPLITUDe of the sensory potential of the PN(--46 per cent). The other parameters studied in group II did not show any significant difference in comparison with the control group. These results indicate that PN is involved early in a complex fashion in latent alcoholic neuropathies. They confirm that the distinction between axonal neuropathy and segmental demyelination is rarely absolute.

Adult↗
PubMed1975

The palmo-mental reflex. An electrophysiological study.

Repeated electric stimulation of the ulnar nerve fibers was applied at the wrist in 7 normal and 32 pathological subjects; the response reflexes were simultaneously 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 cutaneous 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 instances 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 suppressed 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 pyramidal tract or the extra-pyramidal formations.

Chin↗
PubMed1975

[Electrophysiological analysis of the blink reflex during hemiplegia due to hemispheric lesions].

Electrical stimulation of the supra-orbital nerve induces at the same threshold an early reflex reaction in the ipsilateral orbicular muscle and a delayed bilateral reflex response. These reflex activities are modified bilaterally by unilateral hemispheric lesions. Reactions on the hemiplegic side are reduced in amplitude, unlike the responses on the "healthy side" which are facilitated. Adaptation of the reflexogenous threshold of the delayed responses to repeated stimulation is also irregular; cumulative depression occurs earlier on the hemiplegic side, the responses on the "healthy side", on the other hand, show less habituation or a total absence of it. These electrophysiological findings agree with experimental results concerning the influence of cortical structures on the activity of the nuclei of the brain stem. They also, by analogy with the results of research carried out on the limbs, support the tactile origin of the two constituents of the blink reflex.

Brain Diseases↗