Effect of systemic tetracycline and amoxicillin on inflammatory root resorption of replanted dogs'' teeth

Upper motor neuron lesion in adults is usually associated with spasticity and "extensor toe sign" on plantar stimulation (extensor plantar response). There are various methods of eliciting this sign including the classic method by Babinski. Other methods produce this response when the area of reflexogenic zone is increased due to upper motor neuron lesion. There are varying reports of Babinski positivity in spastic cerebral palsy. This study was undertaken to assess the sensitivity of different methods of eliciting "extensor toe sign." An attempt has also been made to correlate the severity of spasticity with the combined "extensor toe sign" positivity by various methods and with the increase in reflexogenic zone. Eighty-one children with spastic cerebral palsy were examined. Twelve had hemiplegia; therefore, a total of 150 limbs were tested. "Extensor toe sign" was elicited by 12 different methods in each patient. The sensitivity of each method was calculated and compared with each other one. The assessment of spasticity was done using the Ashworth Tone Scale. The severity of spasticity was correlated with "extensor toe sign" positivity using various methods. Classic Babinski reflex was positive in 75% of cases, whereas Gonda-Allen sign was positive in 90% of cases followed by Allen-Cleckley (82%), Chaddock (74%), and Cornell (54%). All other signs had sensitivity of less than 30%. There was no increase in sensitivity after combining them. There was significant negative correlation between the spasticity and the combined "extensor toe sign" positivity (by all the methods). This study, therefore, suggests that the majority of patients with spastic cerebral palsy have positive "extensor toe sign." The Gonda-Allen method is more sensitive than the classic Babinski method. A positive "extensor toe sign" is negatively correlated to the degree of spasticity.     

H-reflex and F-wave potentials in leg and arm muscles

The systematic analyses of secondary muscle potentials of H-reflex and F-wave type were done in multicentric study. The examinations were carried out in healthy volunteers with 9 muscles analysed on the legs and 9 on the lower arms and hands. The H-reflex potential was found regularly in thigh muscles (vastus medialis 100%, biceps femoris 97%, semitendinosus 93%). Less frequently but still with high incidence it appeared in posterior lower leg muscles (soleus 93%, caput mediale gastrocnemii 73%). In anterior tibial muscle and extensor digitorum brevis it did not appear at all. Only exceptionally it was found in short peroneal muscle (3%) and occasionally, only on proximal nerve stimulation, in flexor hallucis brevis. The similar distribution pattern was found in lower arm and hand muscles with analysis on both sides. In flexor digitorum superficialis (73-70%) and flexor carpi radialis (73-57%) the percentage of H-potential muscles was the highest, in flexor carpi ulnaris (47-40%) lesser but still remarkable. Brachioradialis (37-30%) and extensor digitorum communis (27-27%) percentage decreased further. The even more distal, pronator quadratus (21-20%) and abuctor digiti minimi (17-17%) presented as muscles with low incidence of H-reflex positivity. In extensor indicis proprius (3%) the lowest H-potential incidence was found and in opponens pollicis no H-potential at all. F-waves if evaluated as "F-frequency" follow the similar distribution pattern. The lowest "F-frequency" was found on the legs in anterior tibial, short peroneal and extensor digitorum brevis muscles. In the last one more than one half of stimuli failed to evoke the F-potential. Those are the muscles in which H-potentials almost never appeared. The highest "F-frequency" was recorded in thigh, posterior lower leg muscle and flexor hallucis brevis. Some of the examinees displayed in almost all examined muscles H-potential (6 of 30), the others (9 of 30) had it in neither one or in a single muscle. It looks like as if a kind of H-reflex or F-wave individuals exist. If the H- or F-potentials distribution pattern got projected on the homunculus in quadrupedal position the following idea appears. The thigh muscles, the plantar flexors of the feet and hand and finger flexors are first of all tonic muscles mostly involved in standing or holding. The extensors of the foot/toes, respectively of hand/fingers interrupt phasically the sustained action of standing by lifting the foot/hand from the ground. The muscles with mostly tonic function produce much H-reflexes, transitional forms or at least F-wave with high "F-frequency". Is that a kind of phylogenetical remnants, better developed in the motorically less differentiated legs? Have the H-reflex muscles if compared with F-wave muscles different motor units structure? Have they different motoneurons, with different liability to produce recurrent discharges?     

Neurologic signs in lumbar disc herniation. Preoperative affliction and postoperative recovery in 150 cases

We studied prospectively 165 consecutive patients operated on for lumbar disc herniations. Neurologic examination was performed preoperatively and at 4, 12, and 24 months postoperatively according to a protocol. Preoperatively 69% of the patients showed a neurological disturbance corresponding to the level of disc herniation and 62% a corresponding sensory deficit. Recovery of the neurological deficit was seen in half of the cases at 2 years postoperatively, the main part of this improvement occurred within 4 months after the operation. Neurologic recovery correlated to a good surgical outcome, and a short history of disc herniation prior to the operation correlated to postoperative neurologic improvement. The straight leg raising test correlated to preoperative neurologic deficit, but not to postoperative recovery. Motor power disturbance of the extensor hallucis longus muscle recovered in more patients than reflex disturbances. Sensory disturbances had the lowest recovery rate. Our study demonstrates a correlation between routine postoperative neurologic findings and the patient's self-assessed outcome of surgery.     

Characteristics of locomotor control in children with cerebral palsy

The typical features of electromyographical (EMG) recordings from children with cerebral palsy (CP) consist of a coactivation of antagonistic leg muscles during the stance phase, a low and tonic activation of extensor EMG, and enhanced stretch reflex excitability with short latency. This characteristic reflex pattern is suggested to reflect an arrested normal maturation. The strong similarity between the walking pattern of CP children (8-16 years of age) and the reflex pattern during the process of learning to walk (7-10 months of age) lets us draw the following conclusion. During normal maturation a close parallelism exists between the control of group I afferent inhibition with the suppression of mono/oligosynaptic stretch reflexes and group II afferent facilitation with the increase of polysynaptic (mainly extensor) EMG responses. This maturation depends on supraspinal control, and does not occur in CP children. In adult patients with a supraspinal lesion, a regression to this early reflex pattern takes place.     

Motor-unit recruitment in self-reinnervated muscle

1. Recruitment order of motor units in self-reinnervated medial gastrocnemius (MG) muscles was studied in decerebrate cats 16 mo after surgical reunion of the cut MG nerve. Pairs of MG motor units were isolated by dual microelectrode penetration of ventral roots to measure their recruitment sequence during cutaneous reflexes in relation to their physiological properties. 2. Physiological properties of reconstituted motor units appeared normal, as expected. Also normal were the relationships among these properties: twitch and tetanic tension tended to increase with axonal conduction velocity and decrease with twitch contraction time. A small fraction of motor units (10/116) in reinnervated muscles produced either no measurable tension or unusually large amounts of tension compared with controls. This was the only distinct feature of the sample of reconstituted units. 3. In muscles reinnervated after nerve section, stretch was notably ineffective in eliciting reflex contraction of MG muscles or their constituent motor units (only 5/116 units). Incomplete recovery from nerve section was probably the cause of this impairment, because stretch reflexes were readily evoked in adjacent untreated muscles and in one reinnervated MG muscle that was studied 16 mo after nerve crush. In contrast with the ineffectiveness of muscle stretch, sural nerve stimulation succeeded in recruiting 49/116 units, a proportion fairly typical of normal MG muscles. 4. The contractions of the first unit recruited in cutaneous reflexes tended to be slower and less forceful than those of the other unit in a pair. By these measures, recruitment obeyed the size principle. This recruitment order with respect to unit contractile properties was not significantly different (P > 0.05) between untreated and reinnervated muscles but was significantly (P < 0.005) different from random order in both groups. The same recruitment pattern was observed for pairs of motor units sampled from the muscle reinnervated after nerve crush, whether units were recruited by muscle stretch or sural nerve stimulation. 5. The usual tendency for motor units with slower conduction velocity (CV) to be recruited in sural nerve reflexes before those with faster CV was not strong in reinnervated muscles. After nerve section the proportion of units exhibiting the usual recruitment pattern was not significantly different (P > 0.05) from a random pattern for CV. 6. The central finding is that the normal recruitment patterns recover from nerve injury in a muscle that is reinnervated by its original nerve. By contrast, stretch reflexes do not recover well from nerve section, and this deficiency may contribute to motor disability.     

Behavioral development and strain differences in perinatal mice (Mus musculus).

Examined the perinatal development of spontaneous body movements and reflexes in Slc:ICR, C3H/He, and BALB/c mice. Mice were observed from Day 18 (a day before normal parturition) to Day 21.5 of gestation. The developmental changes of spontaneous body movements and reflexes occurred quickly. Strain differences in behavioral development were detected in the duration of spontaneous body movements but not in the occurrence of reflexes. Hybrid mice were more active than their parental strains with regard to duration of spontaneous body movements. The rooting reflex and crossed extensor reflex in hybrid mice occurred more frequently on Day 18 than in their parental strains. These results indicate that the perinatal period is characterized by quick qualitative and quantitative changes in behavioral development and by the appearance of these genetic differences. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Evolutionary origins of two tightly linked mutations in arylsulfatase-A pseudodeficiency

Recordings of withdrawal reflexes have been used extensively to study sensory-motor integration and processing of nociceptive information in the spinal cord. We describe here a new technique for the manufacture of improved EMG electrodes that permit the characterisation of the physiological properties of single motor units as well as the easy location of the muscles studied. Individual motor units from three rat hind-limb muscles: peroneus longus, tibialis cranialis and extensor digitorum longus, were activated by thermal and mechanical stimulation applied to their cutaneous receptive fields, which were located mainly on the 4th and 5th toes. Thresholds for thermal and mechanical (Von Frey hairs) stimulation were similar in the three muscles studied, with a value of 44 +/- 1 degrees C and 100 mN (median), respectively. However, when a mechanical pincher with a stimulus area of 14 mm2 was used, the values seen were similar for peroneus longus and tibialis cranialis (342 +/- 23 and 330 +/- 71 mN, respectively, mean +/- S.E.M.) but lower for extensor digitorum longus (220 +/- 37 mN, mean +/- S.E.M.). The firing rate of the single motor units was similar for all types of stimulation at threshold intensity, and showed a linear relationship with stimulus intensity, except for units of the tibialis cranialis, which showed a greater degree of adaptation.     

Effects of postural changes of the upper limb on reflex transmission in the lower limb. Cervicolumbar reflex interactions in man

The influence of passive changes in upper limb position on the excitability of three myotatic arc reflexes (soleus, quadriceps, and biceps femoris) of the lower limb has been explored on 42 volunteers. The results indicate that the excitability of the three myotatic arcs can be influenced at a distance by postural modifications of the upper limb. When the ipsilateral upper limb is forwards or the contralateral backwards, a facilitation of both soleus and quadriceps tendon reflexes is observed while the biceps femoris reflexes are reduced. This pattern of facilitation and inhibition is reversed when the ipsilateral upper limb is backwards or the contralateral forwards. The facilitations as well as inhibitions of proximal myotatic arc reflexes are quantitatively more marked than that of the soleus reflex. Facilitation and inhibition are not linearly related to the angle of the arm with the trunk. Effects begin at a considerable angle, become maximal at 45 degrees, and progressively disappear for greater values. It is suggested that the distinct pattern of facilitation and inhibition which is exerted in reciprocal fashion on extensor and flexor motor nuclei might depend on the long propriospinal neurones connecting cervical and lumbar enlargements.     

Assessment of spasticity in hemiplegic cerebral palsy. II: Distal lower-limb reflex excitability and function

A clinical method for measuring the stretch reflex threshold and gain of muscles acting across the ankle joint in children with congenital hemiplegia is described. The stretch reflexes of all limbs were velocity-dependent. Hemiparetic limbs were not necessarily spastic compared with non-paretic limbs, suggesting that the term 'spastic hemiplegia' should be used more selectively and emphasis be placed on the heterogeneity of the hemisyndromes of childhood. Abnormal motor control, planning and dexterity, the hemipostures and plastic (non-electrical) muscle changes may be more important measures of impairment than reflex excitability. A general scheme for assessing reflex excitability and available treatments applicable to all types of cerebral palsy is proposed.     

Electrical study of jaw and orbicularis oculi reflexes after trigeminal nerve surgery

Trigeminal nerve ophthalmic and motor division function was assessed clinically and electrically in 32 patients who had undergone various surgical procedures for trigeminal neuralgia. Using known electrophysiological techniques, the orbicularis oculi and jaw reflexes were tested in all subjects. Abnormalities of the orbicularis oculi reflex were anticipated on the basis of ophthalmic division anaesthesia. However, jaw reflex abnormalities appeared in operated cases with no clinical or electromyographic evidence of masseter denervation. These results were unexpected, and imply that the proprioceptive fibres of the jaw reflex are mediated by a sensory and not a motor root as previously believed.     

The influence of recombinant human tumor necrosis factor alpha and its muteins used alone or in combination with 2-chlorodeoxyadenosine on normal and leukemic hematopoiesis in vitro

We report an 80-year-old woman with progressive muscular atrophy predominantly involving her right lower extremity. She was well until 1992 (75 years of age) when she noted an onset of weakness in her right leg which had got progressively worse. She was admitted to our service in July 1994. On admission, general physical examination was unremarkable. She was alert and well oriented without dementia. Higher cerebral functions were normal. Cranial nerves also appeared intact. She dragged her right leg in walking. Mild to moderate weakness (2/5 to 4/5) was noted in muscles in her right lower extremity more in the distal part. Deep tendon reflexes were within normal limits, and the plantar response was flexor bilaterally. Sensation was intact. Laboratory examinations were also unremarkable except for slight increase in CK which was 470 IU/l. CSF was also normal. EMG revealed neurogenic changes in the lower extremities. She was admitted to Aoki Hospital on October 21, 1994, by that time, her weakness in the right lower extremity had gotten worse in that the muscle strength of the right extensor hallucis longus was 0 and tibialis anterior 2; muscle atrophy was also prominent in her right leg; the right ankle jerk could not be elicited. In the subsequent course, weakness and atrophy appeared in her left lower extremity, however, upper extremities and cranial nerves had never been affected. Babinski sign was always negative. In February 1996, she developed delusional ideation of self persecution, and showed difficulty in communication with medical staffs. She developed fever of 38.7 degrees C on June 13, 1996 expired on the next day. The patient was discussed in a neurological CPC, and the chief discussant arrived at the conclusion that the patient had a form of spinal muscular atrophy. Opinions were divided between ALS and spinal muscular atrophy. Post-mortem examination revealed marked loss of anterior horn neurons in the lumbar area with astrogliosis. Bunina bodies were seen in some of the remaining neurons. No myelin pallor was noted in the pyramidal tracts, however, atrophy and loss of Betz cells were noted in the motor cortex. Other cortical areas were unremarkable. The neuropathologist arrived at the conclusion that the patient had ALS. This patient was unique in that she had asymmetric atrophy and weakness limited to the lower extremities. This is quite unusual as ALS of four years duration. In addition, the patient developed some mental change which was thought to represent dementia by some participants. But no clear morphologic changes were seen to account for her mental change.     

Dynamic control of location-specific information in tactile cutaneous reflexes from the foot during human walking

The purpose of the present study was to determine whether tactile cutaneous reflexes from the skin of the foot contain location-specific information during human walking. Muscular responses to non-nociceptive electrical stimulation of the sural, posterior tibial, and superficial peroneal nerves, each supplying a different skin area of the foot, were studied in both legs during walking on a treadmill. For all three nerves the major responses in all muscles were observed at a similar latency of approximately 80-85 msec. In the ipsilateral leg these reflex responses and their phase-dependent modulation were highly nerve-specific. During most of the stance phase, for example, the peroneal and tibial nerves generally evoked small responses in the biceps femoris muscle. In contrast, during late swing large facilitations generally occurred for the peroneal nerve, whereas suppressions were observed for the tibial nerve. In the contralateral leg the reflex responses for the three nerves were less distinct, although some nerve specificity was observed for individual subjects. It is concluded that non-nociceptive stimulation of the sural, posterior tibial, and superficial peroneal nerves each evokes distinct reflex responses, indicating the presence of location-specific information from the skin of the foot in cutaneous reflexes during human walking. It will be argued that differentially controlled reflex pathways can account for the differences in the phase-dependent reflex modulation patterns of the three nerves, which points to the dynamic control of this information during the course of a step cycle.     

Central and peripheral actions of the NSAID ketoprofen on spinal cord nociceptive reflexes

Ketoprofen is a non-steroidal antiinflammatory drug (NSAID) which provides effective analgesia in situations of pain provoked by tissue inflammation. However, the location of its analgesic effects, (peripheral tissues versus central nervous system), have not been clearly identified and separated. In the present study the effectiveness of ketoprofen was examined in two different types of experiments: (i) Open field behavioural tests in conscious rats, and (ii) spinal cord nociceptive reflexes (single motor units) activated by electrical and thermal stimulation in chloralose anaesthetised rats. The experiments were performed in rats with carrageenan-induced inflammation of one hindpaw, or of one knee joint. The administration of ketoprofen significantly inhibited the reduction of exploratory movements caused by inflammation in open field experiments. Ketoprofen was also effective in depressing reflex activity evoked by electrical and noxious thermal stimulation of the skin, either in inflamed tissue or in normal tissue of monoarthritic animals. It was also effective in the reduction of reflex wind-up; a phenomenon in which the activity of spinal cord neurones increases progressively with high frequency electrical stimulation. We therefore conclude that ketoprofen has central as well as peripheral analgesic activity.     

Pseudoparalytic myasthenia gravis. Diagnostic and therapeutic aspects in 60 separate cases

Based on 60 of our own cases and on the medical literature the authors discuss the diagnostic, pathophysiological and therapeutic aspects of myasthenia gravis. Myasthenia is suspected in cases of motor weakness of changing intensity, diminishing by rest. The weak muscles are innervated by different peripheral nerves. At the beginning a weakness of upperlid-muscles, external eye muscles and bulbar muscles is particularly frequent. There is no sensory loss or other neurological symptoms. A transitory disappearance of motor weakness after an intravenous dose of Edrophonium (Tensilon) is a typical diagnostic sign. The effect is less evident with eye-muscle weakness. A typical appearance of potentials after repetitive stimulation of peripheral nerves as well as other characteristics in electrophysiological testing of muscles are of high diagnostic value. This allows differentiation from other types of muscle weakness. In the pathogenesis of myasthenia an autoimmune process related to a persistent thymus gland plays an important part. This leads to an ultrastructural change in the postsynaptic membrane of the muscle fibre. The postsynaptic membrane no longer reacts in a normal way to acetylcholine as a transmitter substance at the level of the motor endplate. Therefore the first step in the treatment of myasthenia consists of cholinesterase-inhibitors, specially Neostigmin (Prostigmin) and Pyridostigmin (Mestinon). Thymectomy is advised in all cases of myasthenia with the exception of the pure ocular form and of myasthenia in patients older than 60 years. The thymus gland is practically always persistent or hypertrophic in myasthenia. The suprasternal access is recommended. A thymoma should always be operated upon because of the danger of malignancy. In cases where thymectomy is not performed or not successful and if cholinesterase-inhibitors are not sufficiently efficient, treatment with corticosteroids or ACTH is recommended.     

123I-MIBG myocardial scintigraphy in diabetic patients: relationship with 201Tl uptake and cardiac autonomic function

The purpose of this study is to investigate the effects of aging on the human stretch reflexes. The EMG and torque responses of the stretch reflex of the wrist flexors were evoked by ramp-and-hold mechanical perturbations. The stretch reflexes were recorded at seven test conditions with different stretch velocity and muscle preload. The test results from young and older healthy adult subjects were compared. In average, the absolute amplitude of the short-latency (20-40 ms) EMG (recorded from flexor carpi radialis) reflex response was significantly lower in the older group. If the data were normalized and expressed in percentage of the maximal voluntary EMG activity, however, this group difference was not significant. There was no change in the reflex gain of the short-latency reflex with aging. For the long-latency (50-90 ms) EMG reflex response, both the normalized amplitude and the reflex gain were significantly enhanced with aging, probably through supraspinal mechanisms. There was no significant difference in the threshold velocity for the evoked EMG reflexive activities between age groups. There were also no changes in the reflexive wrist flexion torque with aging. These results suggested that the number of motor units recruited during the stretch reflex activity declined with aging although the percentage of motor units recruited was not affected by aging. It is concluded that the central regulating mechanisms of the spinal motoneuron excitability are not compromised by aging. The automatic gain compensation phenomenon is also preserved with aging.     

Stretch reflex and servo action in a variety of human muscles

1. In the long flexor of the thumb the latency of the stretch reflex and of other manifestations of servo action is some 45 msec, roughly double the latency of a finger jerk. 2. Tendon jerks are feeble or absent in the long flexor of the thumb even in subjects with brisk long-latency stretch reflexes in this muscle. This, and other facts, suggests that the nervous mechanism of the tendon jerk is different from that of the stretch reflex. 3. A muscle that has feeble tendon jerks may show a late component in the response to a tendon tap, with a latency similar to that of the long-latency stretch reflex. 4. On the hypothesis that the excess latency of the stretch reflex over that of a tendon jerk is because the stretch reflex employs a cortical rather than a spinal arc, the excess would be expected to be larger in magnitude for the long flexor of the big toe and smaller for the jaw closing muscles. This is confirmed, 5. An alternative hypothesis that the long latency of stretch reflexes in thumb and toe is because they are excited by slow-conducting afferents is made improbable by the finding that stretch reflexes with an equal or greater excess latency are also found in proximal arm muscles. 6. The long-latency stretch reflex in proximal muscles was seen most distinctly in a healthy subject who happened to have feeble or absent tendon jerks. In ordinary subjects there is often a large, short-latency, presumably spinal component of the stretch reflex in proximal muscles; and short-latency responses to halt and release are also seen, The significance of this spinal latency servo action in proximal muscles remains to be explored. 7. The Discussion argues that the available data on conduction time to and from the cerebral cortex are compatible with the hypothesis that the long-latency component of the stretch reflex uses a transcortical reflex arc, and that none of the experiments described in the present paper are inimical to this view.     

Patterns of GFAP-immunoreactivity parallel the tonotopic axis in the developing dorsal cochlear nucleus

The gain of the H reflex attenuates during passive stepping and pedalling movements of the leg. We hypothesized that the kinematics of the movement indirectly reflect the receptor origin of this attenuation. In the first experiment, H reflexes were evoked in soleus at 26 points in the cycle of slow, passive pedalling movement of the leg and at 13 points with the leg static (the ankle was always immobilized). Maximum inhibition occurred as the leg moved through its most flexed position (P < 0.05). Inhibition observed in the static leg was also strongest at this position (P < 0.05). The increase in inhibition was gradual during flexion movement, with rapid reversal of this increase during extension. In the second experiment, the length of stretch of the vasti muscles was modelled. Variable pedal crank lengths and revolutions per minute (rpm) altered leg joint displacements and angular velocities. Equivalent rates of stretch of the vasti, achieved through different combinations of joint displacements and velocities, elicited equivalent attenuations of mean reflex magnitudes in the flexed leg. Reflex gain exponentially related to rate of stretch (R2 = 0.98 P < 0.01). The results imply that gain attenuation of this spinal sensorimotor path arises from spindle discharge in heteronymous extensor muscles of knee and/or hip, concomitant with movement.     

Spasticity in rats with sacral spinal cord injury

We have investigated sacral spinal cord lesions in rats with the goal of developing a rat model of muscular spasticity that is minimally disruptive, not interfering with bladder, bowel, or hindlimb locomotor function. Spinal transections were made at the S2 sacral level and, thus, only affected the tail musculature. After spinal transection, the muscles of the tail were inactive for 2 weeks. Following this initial period, hypertonia, hyperreflexia, and clonus developed in the tail, and grew more pronounced with time. These changes were assessed in the awake rat, since the tail is readily accessible and easy to manipulate. Muscle stretch or cutaneous stimulation of the tail produced muscle spasms and marked increases in muscle tone, as measured with force and electromyographic recordings. When the tail was unconstrained, spontaneous or reflex induced flexor and extensor spasms coiled the tail. Movement during the spasms often triggered clonus in the end of the tail. The tail hair and skin were extremely hyperreflexive to light touch, withdrawing quickly at contact, and at times clonus could be entrained by repeated contact of the tail on a surface. Segmental tail muscle reflexes, e.g., Hoffman reflexes (H-reflexes), were measured before and after spinalization, and increased significantly 2 weeks after transection. These results suggest that sacral spinal rats develop symptoms of spasticity in tail muscles with similar characteristics to those seen in limb muscles of humans with spinal cord injury, and thus provide a convenient preparation for studying this condition.     

Polyneuropathies from solvents

Polyneuropathy is a clinically diagnosed disorder. The diagnostic features consist mainly of subjective complaints about distally marked paresthesia or dysaesthesia, pain and motor disturbances like cramps. Neurological examination typically shows weak or absent tendon reflexes (early signs: weak or absent Achilles tendon reflexes), distally marked disturbances of sensitivity (early sign: reduced sense of vibration), atrophic paresis, cranial nerve impairment and disturbances of the autonomic nervous system. Results of additionally performed electrophysiological examinations (nerve conduction studies, vibratometry and thermotesting) contribute to the diagnosis. Polyneuropathy is undoubtedly induced by carbon disulfite, ethylene glycol, n-hexane and methyl-n-butylketone, triorthocresyl phosphate and solvent mixtures. Induction of polyneuropathy is doubtful with the following substances: tetrachloride, trichlorethylene, styrene, toluene. Additional impairment of the central nervous system is often indicated by clinical findings of brisk patellar tendon reflexes or the occurrence of Babinski's sign.     

Myopathology of the intrinsic laryngeal muscles in neurodegenerative diseases, with reference to the mechanism of vocal cord paralysis

To investigate the mechanism of the vocal cord abductor paralysis (VCAP) in the neurodegenerative diseases, the intrinsic laryngeal muscles (the crycothyroid, the interarytenoid, and the posterior crycoarytenoid muscles) from 41 autopsied cases were histologically examined: 10 cases of amyotrophic lateral sclerosis (ALS), 10 of Parkinson's disease (PD), 9 of multiple system atrophy (MSA), 4 of Machado-Joseph disease (MJD), 4 of progressive supranuclear palsy (PSP), 1 of familial amyloidotic polyneuropathy (FAP), and 3 of cerebrovascular diseases as a control. According to the distribution of the neurogenic changes among above-described three intrinsic laryngeal muscles, three forms were raised: 1. The totally paralytic form showing that all the three muscles developed neurogenic atrophy. This form includes ALS, MJD, and FAP. 2. The posterior muscle-paralytic form showing that only the posterior crycoarytenoid muscle was selectively involved. This form includes MSA. 3. The nonparalytic form showing no morphological abnormalities in any of the intrinsic laryngeal muscles. This type includes PD and PSP. In this nonparalytic form, supranuclear mechanism such as pyramidal or extrapyramidal tract involvement may cause VCAP through the increased laryngeal muscles tone. Considering that VCAP can be seen in any of the above-described forms, our results indicate that the mechanism of VCAP is different among the neurological disorders.