Central motor conduction in a family with hereditary motor and sensory neuropathy with pyramidal signs (HMSN V)

Two generations of a family affected by hereditary motor and sensory neuropathy with pyramidal signs (HMSN V) were clinically and electrophysiologically examined. Apart from electroneurographic studies, the central motor conduction (CMC) to arm and leg muscles was assessed using magnetic transcranial motor cortex stimulation. Abnormal CMC was confined to the clinically affected members, with the exception of an unaffected subject who had a diminished but normal latency response in a leg. The typical pattern was a significant diminution of the compound muscle action potential from the tibialis anterior and a moderately prolonged cortico-muscular conduction time (CoMCT) to this muscle.

Visual and brainstem auditory evoked potentials in hereditary motor-sensory neuropathy

Visual evoked potentials (VEP) and brainstem auditory evoked potentials (BAEP) were recorded in 57 children and adults with hereditary motor-sensory neuropathy (HMSN); 37 of them were diagnosed as type I (demyelinating) and 20 as type II (axonal). None of the patients presented central nervous system involvement. The results were compared with VEP and BAEP records of 12 adults with Guillain-Barré syndrome (GBS) and 40 healthy controls. Above 30% of all patients with HMSN I showed delayed latency of the VEP. These abnormalities were less expressed in HMSN II. Abnormal BAEP were observed in almost 50% of patients with HMSN I and HMSN II with nearly the same frequency in both types but more pronounced in HMSN I. The most common feature was prolongation of the I-III interpeak latency (JPL). The VEP and BAEP changes could be present simultaneously in the same patient (mainly in HMSN I) or separately. More often the abnormalities were observed in the adult patients. Normal VEP and BAEP values were present in all patients with GBS. The results strongly suggest the subclinical optical and auditory pathways involvement in HMSN patients.

Clinical and electrodiagnostic findings, nerve biopsy and blood group markers in a family with hereditary neuropathy with liability to pressure palsies

Clinical, electrophysiologic and biopsy findings as well as studies of blood group markers in a family with hereditary neuropathy with liability to pressure palsies (HNPP) are reported. There was an autosomal dominant trait without genetic linkage between the HNPP gene and blood group markers controlled by chromosome 1. Reduced motor and sensory nerve conduction velocity was found in clinically affected and unaffected nerves. Characteristic morphological changes in sural nerve biopsy including tomaculous swelling were present.

Hereditary motor and sensory neuropathy (HMSN) and optic atrophy (HMSN type VI, Vizioli)

Clinical and electrophysiological findings are described in three patients with hereditary motor and sensory neuropathy in association with optic atrophy (HMSN VI). The optic atrophy was of the Leber type in a 15-year-old boy. In a 70-year-old patient, as in three members of his family, optic atrophy was associated with tapetoretinal degeneration. In addition to HMSN and optic atrophy a 20-year-old man suffered from sensorineural deafness. Electrophysiological studies indicated a neuronal form of neuropathy, as in HMSN II. Brainstem auditory evoked potentials also revealed subclinical involvement of the central auditory pathways in the patients without hearing defects.

X-linked dominant hereditary motor and sensory neuropathy

Modern techniques have defined the hereditary motor and sensory neuropathies (HMSN) as a genetically heterogeneous group of disorders. This includes a rare variant with X-linked dominant inheritance. We have traced this disorder through 6 generations of a large Canadian kindred; neurological and electrophysiological examinations were performed in 57 family members and nerve biopsies were studied in 2 affected males, early and late in the disease; 42/83 family members were affected. No male-to-male transmission was encountered in 19 sons of affected fathers, whereas all their daughters expressed the disease. Linkage was shown to the DNA loci DXYS1 Z max = 2.87 at theta max = 0.06 and to PGK1 Z max = 1.51 at theta max = 0 (Beckett et al., 1986). The typical clinical features are onset in early childhood, pes cavus, atrophy and weakness of peroneal muscles and intrinsic hand muscles, and sensory abnormalities. Males were severely affected, whereas females had mild or subclinical disease. Electrophysiological observations indicated a substantial loss of distal motor and sensory nerve fibres. Evoked compound muscle action potentials in extensor digitorum brevis were absent or severely reduced in 42% of cases and the peroneal motor nerve conduction velocity was mildly reduced to a mean 36.5 +/- 7.4 m.s-1. Sural sensory nerve action potentials were absent or severely reduced in 75% of those affected. Nerve biopsies showed loss of myelinated and unmyelinated nerve fibres, regenerative sprouting and secondary demyelination. The findings indicate that this distinct variant of HMSN is the result of primary axonal degeneration.

Hereditary motor and sensory neuropathy type I and type II

In an attempt to clearly identify the different HMSN subgroups, we prospectively evaluated 128 subjects (46 index cases, 39 affected and 43 unaffected relatives) on clinical, genetic and electrophysiological grounds. The diagnosis of HMNS I or II was made in 77 patients. Differential diagnosis between type I and II patients was impossible on clinical grounds alone, but nerve conduction study showed a clear-cut subdivision into two populations. MCV behavior was consistent within families. Inheritance, autosomal dominant in almost all cases, was probably recessive in three HMSN I subjects and pedigree analysis pointed to X-linked transmission in one HMSN I family. We found no evidence for linkage to Duffy locus. We think that similar HMSN phenotypes can be determined by different gene defects. Ulnar nerve F-conduction velocity did not significantly differ from distal MCV in HMSN I: the evidence of a diffuse slowing of nerve conduction supports the hypothesis of a primary myelin defect.

Hereditary motor and sensory neuropathies and hereditary spastic paraplegia: a magnetic stimulation study

Central motor conduction to the small hand muscles was investigated in 59 patients with peroneal muscular atrophy and hereditary spastic paraplegia (HSP) by using transcranial magnetic brain stimulation. These comprised 20 patients with type I hereditary motor and sensory neuropathy (HMSN I), 15 with type II (HMSN II), 4 with HMSN I and 10 with HMSN II with associated pyramidal features, and 10 with the "pure" form of HSP. Central motor conduction was usually normal in HMSN I, HMSN II, and HSP. In HMSN I with pyramidal signs, central motor conduction time was greatly prolonged bilaterally. This result may reflect an associated involvement of the central motor pathways in these patients. In HMSN II with accompanying pyramidal features, 6 of the 10 patients had abnormal central motor conduction, although conduction times were only slightly prolonged, suggesting a different pathophysiological pattern.

The electrophysiologic profile of Dejerine-Sottas disease (HMSN III)

Electrophysiologic studies in 11 patients with Dejerine-Sottas disease (hereditary motor and sensory neuropathy type III, HMSN III) showed median and ulnar motor nerve conduction velocities less than 6 m/sec in all but 1 patient. Marked temporal dispersion without conduction block was present in all patients. Uniform slowing in adjacent motor nerves was consistent with other studies of inherited neuropathies, although marked temporal dispersion may make HMSN III more difficult to distinguish from acquired neuropathies than other hereditary conditions. The electrophysiologic features of HMSN III patients were significantly different from a series of patients with other hereditary neuropathies chosen because of very slow nerve conduction velocity.

[Short-latency somatosensory evoked potentials and magnetic resonance imaging in the medial medullary syndrome]

A 57-year-old woman was admitted to Kakeyu Hospital complaining of paresis of the left upper and lower extremities which suddenly developed three years ago. Neurological examination revealed spastic paresis of the left upper and lower limbs without facial and lingual paresis. The reflexes were abnormally brisk on both sides but they were more remarkable on the left side, which also showed Babinski's sign. Sensitivity to light touch and vibration was moderately decreased and sensitivity to pinprick and joint position was minimally decreased in the left upper and lower extremities. No cerebellar sign was observed. Needle EMG disclosed large motor units with an amplitude of 4-5 mV and a duration of 8 msec in the light half of the tongue during weak contraction. MRI using a 0.5-T superconducting magnetic resonance unit detected a small, wedge-shaped infarction in the anterior medial portion of the medulla just below the pontomedullary junction. Somatosensory evoked potentials (SEPs) after median nerve stimulation with a non-cephalic reference were recorded. After stimulation of the left side, the scalp-recorded P13 was recognized at the normal latency, but the later components, N16 and N18, were apparently absent. On the other hand, SEPs in another case with thalamic hemorrhage revealed normal N16 potential with absence of N18 on the affected side. From these SEP findings and the reports on SEPs in lesions of the brain stem or thalamus, it was suggested that P13 is abnormal in lower medullary lesions and is preserved in upper medullary lesions, and that N16 is abnormal in brain stem lesions and is preserved or changed a little in thalamic lesions.

A quantitative study of sensory function in hereditary spastic paraplegia

Somatic sensation was studied in 23 patients from 14 families with hereditary spastic paraplegia. Quantitative sensory testing revealed significantly raised thermal, heat pain, vibratory and tactile thresholds in patients as compared with normal controls. Cutaneous sensitivity was more severely impaired in the feet than in the hand. All patients had at least one elevated sensory threshold. Sensory nerve conduction studies were abnormal in 6 patients, 5 of whom were members of the same family. Somatosensory evoked potentials were reduced on average to half the size of those of controls. Although the clinical picture is dominated by a spastic paraparesis, subclinical sensory impairment is common in hereditary spastic paraplegia and may reflect involvement of peripheral nerves, afferent pathways in the spinal cord or both.

Hyperopia in complicated Leber's congenital amaurosis

We studied the refractive status of 13 children with Leber's congenital amaurosis. Seven had the disease complicated by neurological or other systemic abnormalities, while the other 6 patients had only ophthalmic abnormalities. All 13 patients were hyperopic. The magnitude of hyperopia did not differ significantly between the complicated and uncomplicated groups. Therefore, one cannot, as previously suggested, use the presence of high hyperopia to differentiate an uncomplicated form of Leber's congenital amaurosis from one complicated by neurologic or other systemic abnormalities. The concurrence of hyperopia with Leber's congenital amaurosis should not steer the physician away from careful neurologic systemic or biochemical evaluation of the child.

[A case of hereditary motor and sensory neuropathy of neuronal type with retardation of motor development]

An atypical case of hereditary motor and sensory neuropathy of neuronal type with retardation of motor development was described. The patient was a 15-year-old boy who had suffered from distal muscle weakness with atrophy of four limbs and deformities of hands and feet since age 6 months. These symptoms were slowly progressive. He had never walked. His parents were not consanguinous. His parents and two siblings were unremarkable on neurological examination and on nerve conduction studies. On neurological examination, he showed severe degree of muscle weakness and atrophy in the distal upper and lower limbs, moderate degree of muscle weakness and atrophy in the proximal upper limbs and slight degree of made weakness and atrophy in the proximal upper limbs. Deep tendon reflexes in four limbs were decreased or absent. Vibration sensation was moderately decreased in the distal parts of four limbs. On the nerve conduction studies, no sensory nerve potential was recorded in the median, ulnar and sural nerves bilaterally. Motor nerve conduction velocity of the right tibial nerve was 21 m/sec and the amplitude of the compound muscle action potential (M-wave) was 0.15 mV, and no M-wave was elicited with the electrical stimulation of the median, ulnar and peroneal nerves. Neelde EMG showed fibrillation potentials and giant spikes with a reduction of the number of motor units. On sural nerve biopsy, the densities of both myelinated and unmyelinated fibers were severely decreased.(ABSTRACT TRUNCATED AT 250 WORDS)

BAEP changes in Leber's hereditary optic atrophy: further confirmation of multisystem involvement

A neurophysiological study of 11 patients belonging to 5 families affected by Leber's hereditary optic atrophy is reported. Electromyography, nerve conduction velocities and somatosensory evoked potentials were normal. Visual evoked potentials were absent or delayed, desynchronized and reduced in amplitude. Brainstem auditory evoked potentials were anomalous in 64% of subjects all without hearing defects. These changes which have never before been reported, confirm multisystem involvement in this disease.

Neuropathy in Navajo children: clinical and epidemiologic features

We describe a rare and apparently unique neuropathic syndrome among Navajo children living on the Navajo Reservation. Clinical features include sensorimotor neuropathy, corneal ulcerations, acral mutilation, poor weight gain, short stature, sexual infantilism, serious systemic infections, and liver derangement including Reye's syndrome-like episodes. Progressive CNS white matter lesions were diagnosed through magnetic resonance imaging. We identified 20 definite and 4 probable cases occurring between 1959 and 1986. Mean age at the time of 1st recognized symptom was 13 months (range, 1 month to 4 years 6 months). Ten individuals have died; 6 of the deaths occurred before 5 years of age. The incidence of this syndrome on the western Navajo reservation is 5 times higher than that on the eastern reservation (38 compared with 7 cases per 100,000 births). Although the etiology is unknown, this syndrome is consistent with an inborn error of metabolism, inherited in an autosomal recessive manner.

Visual and neural function in Leber's optic neuropathy

This report details the chronology of vision loss for an 18-year-old Caucasian male with Leber's optic neuropathy. Findings of an oculo-visual assessment with auxiliary in-office tests of visual neural function, results of neurophysiological testing, and rehabilitative therapy with low vision aids are presented. The clinical characteristics of this devastating disorder are reviewed.

Polyneuropathies in paediatrics

Non-acute polyneuropathies (PNPs) encountered in paediatrics are reviewed. Emphasis is placed on three main groups of conditions: the relatively rare but treatable dysimmune PNP (chronic relapsing dysimmune polyneuropathies, CRDP); the more common hereditary motor/sensory neuropathies (HMSN and HSN); and the often missed symptomatic neuropathies of some heredodegenerative and neurometabolic disorders. Diagnostic procedures are discussed. One conclusion drawn is that so far metabolic screening procedures do not give any diagnostic or aetiological information in HMSN or in HSN, nor in heredoataxias or heredoparaplegias. When a specific neurometabolic disease is suspected from the clinical symptomatology, individually structured investigations are necessary.

A family with tomaculous neuropathy mimicking Charcot-Marie-Tooth disease

The appearance of Guillain-Barré syndrome in a 9-year-old girl led to the detection of a hereditary neuropathy in her family. This neuropathy showed clinical and electrophysiological characteristics of Charcot-Marie-Tooth disease. Only nerve biopsy performed in a sister of the proband allowed diagnosis of tomaculous neuropathy which presented unusual clinical, electrophysiological and bioptic aspects.

Neurophysiology of fastest voluntary muscle contraction in hereditary neuropathy

In patients with hereditary motor and sensory neuropathy types I (demyelinative) and II (neuronal) and in normal subjects, isometric force and electromyographic activity of the first dorsal interosseous muscle were recorded during fastest voluntary contractions and during twitches evoked by nerve stimulation. The maximum voluntary force of the first dorsal interosseous muscle was also measured. In patients, fastest voluntary contraction time (i.e., time from onset of contraction to peak force) was prolonged and inversely proportional to maximum voluntary force. Maximum rate of rise of tension (i.e., slope of rise in force) was reduced and directly proportional to maximum voluntary force. In patients with hereditary motor and sensory neuropathy type I, contraction time was longer and the maximum rate of rise of tension was lower than in those with hereditary motor and sensory neuropathy type II. In patients and normal subjects, voluntary contraction time was closely correlated with the duration of electromyographic bursts. In patients, the twitch contraction time was prolonged and inversely proportional to maximum voluntary force. Twitch contraction amplitude was diminished and directly proportional to maximum voluntary force. Neither twitch contraction time nor amplitude were dependent on the type of hereditary motor and sensory neuropathy. Twitch contraction time evoked by proximal nerve stimulation was minimally longer than that evoked by distal stimulation.(ABSTRACT TRUNCATED AT 250 WORDS)

Attenuated SEPs with no latency shifts in a family with hereditary spastic paraplegia

Five siblings with hereditary spastic paraplegia of autosomal-dominant inheritance were studied with somatosensory evoked potentials. Somatosensory evoked potentials were recorded from Cz', T12, and the left popliteal fossa following left posterior tibial nerve stimulation. The latency and amplitude of the corresponding potentials (i.e., P37, N20, and N7) were compared with normal values obtained from age- and height-matched controls. There was no significant difference in the values of N7, suggesting an intact afferent peripheral pathway; in contrast, the amplitudes of P37 and N20 were decreased with normal latencies. The degree of amplitude decrease correlated with the severity of vibration sense impairment in the lower limbs. These results appear to support selective axonopathy of the centrally directed axons of the dorsal root ganglion cells. Furthermore, our results suggest that different degrees of dorsal column involvement in hereditary spastic paraplegia can cause different types of somatosensory evoked potential abnormalities, namely, attenuated amplitudes with no latency shifts, as recorded in this family, and the prolonged latencies, as reported previously.

Longitudinal study of neuropathic deficits and nerve conduction abnormalities in hereditary motor and sensory neuropathy type 1

We measured neuropathic deficit (neurologic disability score [NDS]) and attributes of nerve conduction in hereditary motor and sensory neuropathy (HMSN 1) in cross-sectional evaluation of 69 patients and in longitudinal evaluation over approximately 15 years in 31 of them. Neuropathic deficit worsened by 0.6 NDS point per year in patients 5 to 14 years old at first evaluation, by 1.1 points in patients 15 to 39 years old, and by 0.9 point in patients 40 or more years old. Neuropathic deficit was greater in HMSN 1b (the disorder linked to Duffy) than in HMSN 1a (not linked to Duffy). Nerve conduction attributes changed significantly depending on attribute studied, age, and nerve. In patients evaluated serially, ulnar conduction velocity (CV) increased by a few meters per second in patients who were 5 to 14 or 15 to 39 years old at first examination, but decreased in patients who were older. In serial measurements, peroneal nerve amplitude decreased in all 3 age groups. We found an association between CV and amplitude or NDS at first and last examinations, suggesting an association between severity of the CV abnormality and neuropathic deficit. The severity of the CV abnormality in the young appears to predict later neurologic abnormality.

[Visual and somatosensory evoked potentials in hereditary motor-sensory neuropathies]

Visual (VEP) and somatosensory evoked potential (SEP) were examined in 31 patients with hereditary motor-sensory neuropathy (HMSN); in the great majority HMSN type I was involved. A prolonged latency of P100 was found only in the two oldest patients, the amplitude of this wave was, however, in adult patients, as compared with the control group, significantly reduced. On examination of SEP a typical finding were N9,N13 waves which were difficult to assess and a spinal wave with markedly prolonged latencies of N20 and P40. The amplitude of these cortical components declined with advancing age. Rather surprisingly the most severe affection of the peripheral sensory and motor neuron was found in the youngest generation of children, while in the older generation of parents the central affection was more marked.

Hereditary motor and sensory neuropathy type I and motor neuron disease. An unusual association

A 34-year-old man experienced progressive muscle weakness and wasting in the shoulder girdle later spreading distally to the upper limbs. Neurological examination revealed signs of pyramidal and bulbar involvement as well as widespread fasciculations. Pes cavus and distal hypoesthesia were also observed. MCV and nerve biopsy findings were consistent with HMSN-I, while EMG pattern suggested a MND. The association of HMSN-I with MND has not been previously described in literature.