Lower motor and primary sensory neuron diseases with peroneal muscular atrophy. II. Neurologic, genetic, and electrophysiologic findings in various neuronal degenerations

Charcot-Marie-Tooth disease: data for genetic counseling relating age to risk

One hundred and nine individuals from complete sibships at risk for autosomal dominant Charcot-Marie-Tooth (CMT) disease in 15 unrelated families were evaluated by physical examination and motor nerve conduction studies. Penetrance of the gene was 28% in the first decade, but was essentially complete by the middle of the third decade. The average age of onset of symptoms was 12.2 y, with a standard deviation of 7.3. Persons at risk who have no clinical manifestations and who are over age 27 have less than a 3% probability of having inherited the CMT gene.

Dominantly inherited hypertrophic neuropathy

Clinical, electrophysiological, and histopathological studies of some members of a family with dominantly inherited hypertrophic neuropathy are presented. Twenty-five members were studied. Seventeen were abnormal on clinical examination. Their ages varied from 2 1/2 to 78 years. Age at onset in 14 of the 17 varied between 2 1/2 and 56 years. Pes cavus and palpable nerve thickening were present in more than half of the affected individuals. All patients had areflexia. Fifteen of the 17 had distal motor weakness as well as mild to moderate sensory impairment. Motor weakness affecting the proximal hip and shoulder girdle muscles was seen in 13 patients. Four patients gave a history of trigeminal neuralgia. Motor nerve conduction velocities were markedly impaired in all the clinically affected members. These studies were normal in the 8 unaffected members. Motor conduction velocities of the proximal segment of the ulnar nerve were slower compared to the distal segment in almost all the affected members. There was no significant correlation between the degree of clinical disability and the extent of impairment in the motor nerve conduction velocities. Sural nerve biopsies were studied. These observations are discussed.

Spastic paraplegia with neurogenic amyotrophy manifesting ballooned axons in sural nerve

A 21-year-old man had progressive symmetric, distal muscle atrophy and weakness, as well as spasticity of the limbs. Histologic examination of the sural nerve disclosed swollen axons containing membranous tubular profiles, ring tubules, large mitochondria with abnormal cristae, and glycogen like granules. Peripheral sensory nerve fibers also were affected. The pathologic features of the peripheral nerves were similar to those of infantile neuroaxonal dystrophy. Sural nerve biopsy may be useful in the study of pathologic processes in spastic paraplegia.

Electrophysiological studies in familial spastic paraplegia

Motor and sensory conduction studies have been performed in 10 patients from three families with uncomplicated familial spastic paraplegia whose ages ranged from 4 to 41 years. In all cases the values fell within the control range. The findings may be contrasted with those in Friedreich's ataxia and some other spinocerebellar degenerations in which peripheral nerve abnormalities are present.

The peroneal muscular atrophy syndrome. Clinical genetic, electrophysiological and nerve biopsy studies. Part 3. Clinical, electrophysiological and pathological correlations

This report analyses correlations between clinical, electrophysiological and pathological data derived from a series of families with peroneal muscular atrophy. It was found that the observed differences between families in median nerve forearm motor conduction velocity were unlikely to be due to differences in the age or severity of the cases. Similarly it it was unlikely that the pathological differences between cases were due to age or severity of the case. The conduction velocity in the Hypertrophic Neuropathy Group tended to increase slightly with age, while that in other cases tended to fall slightly. The conduction velocity and total myelinated fibre counts were inversely related to the degree of segmental demyelination. The Hypertrophic Neuropathy Group and the Intermediate Group of cases were found to behave differently in a number of correlative analyses, thus supporting the suggestion that they represent different disease entities.

The peroneal muscular atrophy syndrome. Clinical, genetic, electrophysiological and nerve biopsy studies. Part 2. Observations on pathological changes in sural nerve biopsies

The light-and electron-microscopic, single teased nerve and morphometric studies of a series of 17 sural nerve biopsies from patients with personeal muscular atrophy are presented. The cases are divided into the following groups according to the criteria of Davis, Bradley and Madrid (1977): Hypertrophic Neuropathy Group; Intermediate Group; Neuronal Sensorimotor Group; Neuronal Motor Group. The Hypertrophic Neuropathy Group had nerve hypertrophy and marked segmental demyelination and onion bulb formation. The Intermediate Group also had segmental demyelilination and onion bulb formation, but nerve hypertrophy was not seen, and axonal degeneration and regeneration were prominent. The Neuronal Sensorimotor Group cases were all sporadic, and showed some onion bulbs, paranodal demyelination and evidence of axonal degeneration and regeneration. The sensory nerve biopsy in the Neuronal Motor Group showed no major abnormality apart from some cluster formation indicating axonal regeneration. The data tend to support the classification of peroneal muscular atrophy proposed by Davis et al. (1977), though there was overlap between the groups in individual pathological parameters.

Clinical description and roentgenologic evaluation of patients with Friedreich's ataxia

The 50 patients in this survey were classified by a panel of neurologists into 4 clinical sub-groups: Group Ia ("typical" Friedreich's ataxia, complete picture), Group Ib ("typical" Friedreich's ataxia, incomplete picture), Group IIa ("atypical" Frriedreich's ataxia, possible recessive Roussy-Levy syndrome), Group IIb (heterogeneous ataxias). The clinical symptoms and signs were analyzed for each of these groups. A constellation of signs constantly present in Friedreich's ataxia and obligatory for diagnosis was described. Other important symptoms, such as the Babinski sign, kyphoscoliosis and pes cavus were found to be progressive, but not essential for the diagnosis at any given time. Finally, a host of other symptoms can only be called accessory. The progression of scoliosis was found to be an important tool in the differential diagnosis of ataxias. Our study also indicates, in contrast to the opinion of some authors, that absent deep tendon reflexes in the lower limbs and early dysarthria are essential in "typical" Friedreich's ataxia.

A family with neurogenic atrophy of the distal muscles of the upper limbs: clinical and electrophysiological studies

A Chinese family manifested mild neurogenic atrophy of the distal muscles of the upper limbs. None of the affected members had sensory abnormalities, or pyramidal tract or bulbar involvement. The onset of the illness was in the middle of the second decade of life. The muscle atrophy was more severe in the female members. Electromyographic examination of the atrophic muscles showed evidence denervation. One female patient demonstrated slow motor conduction velocity in the right median nerve.

Lipid abnormalities in hereditary neuropathy. Part I. Serum non-polar lipids

The non-polar lipids from sera of 54 patients, with various types of hereditary motor and sensory neuropathies, and from 72 healthy subjects were evaluated. A small but highly significant decrease in the percentage of linoleate to total fatty acids in both cholesteryl ester and triglyceride fractions was found in the sera of the neuropathy patients, except in those who had dominantly inherited sensory neuropathy (HSN-I) and who had spinocerebellar degeneration with retinitis pigmentosa and other features (SpC+). A significant decrease of serum lecithin-cholesterol acyltransferase activity was also found in those patients with hereditary motor and sensory neuropathies, Type I and Type II (two types of peroneal muscular atrophy). The biochemical basis of these abnormalities is not apparent. The biochemical abnormalities reported here have been found in several neurologic disorders and hence are unlikely to be disease-specific.

Charcot-Marie-Tooth disease associated with "essential tremor": Report of 7 cases and a review of the literature

A study of 7 cases of Charcot-Marie-Tooth disease associated with a dyskinesia resembling benign essential tremor is presented. In 4 patients, the family history strongly suggested an autosomal mode of transmission, 2 cases were sporadic without an established genetic pattern and 1 was probably recessive. The distal parts of the upper and lower limbs showed imparied muscle strength with slight or no atrophy in 4 patients and conspicuous weakness and wasting in another 2. One patient was a chairbound. Although essential tremor and the tremor seen in these patients are clinically (phenotypically) similar it seems possible that they result from two different genotypes. Further, it seems that cases with Charcot-Marie-Tooth disease and "essential tremor" are not the result of the association of two separate dominant characteristics which are generally inherited as mendelian dominant traits. In spite of the diversity of the clinical manifestations of the peripheral neuropathy, the semiologically different types of essential tremor and the electrophysiological data, it is concluded that patients who develop a peripheral neuropathy on a familial basis and who exhibit clinical features of similar character, suffer from a common type of pathological disorder. Stress is laid upon the fact that Friedreich's ataxia and Charcot-Marie-Tooth disease share many clinical features. It is suggested that when Friedreich's ataxia and Charcot-Marie-Tooth disease seem to be present in the same individual and/or alternate in different members of the same family, the process is likely to be one of Charcot-Marie-Tooth disease. The value of the type of inheritance, natural history, clinical examination and electrophysiological data in differentiating Charcot-Marie-Tooth disease (with or without essential tremor) from other degenerative disorders is analyzed.

Dynamic aspects of peripheral nerve changes in progressive neural muscular atrophy: light- and electronmicroscopic studies of serial nerve biopsies

Serial nerve biopsies were performed at an early, and at an advanced stage of the disease in 2 patients with progressive neural muscular atrophy. The early biopsy showed a complete loss of the large diameter and thickly myelinated fibres, as well as an expansion of the endoneurial interstitium in both cases. Myelinated and unmyelinated fibres exhibited axonal degeneration in all biopsies occasionally. "Onion bulb" formation, a typical feature of peripheral neuropathy in neural muscular atrophy, was found to be prominent only in the latter biopsies. As regards the formal pathogenesis of hypertrophic neuropathy in neural muscular atrophy, axonal dystrophy and interstitial changes of the endoneurium were regarded as primary phenomena, demyelination and "onion bulb" formation as secondary. A possible causal relation between axonal dystrophy and interstitial changes, observed in these cases, is discussed in the light of the present literature.

Non-hypertrophic familial neuropathy associated with intention tremor. A variety of Charcot-Marie-Tooth disease?

A family with an association of sensorimotor neuropathy and intention tremor is reported. Clinical examination of 3 affected family members showed in varying degrees areflexia, muscle wasting, impairment of deep sensation with an ataxic gait, pes cavus and disabling intention tremor. Motor nerve conduction velocities were moderately slowed. A superficial peroneal nerve biopsy showed axonal degeneration without segmental demyelination or onion bulb formation. Our observation seems to indicate an association of intention tremor with the non-hypertrophic variety of Charcot-Marie-Tooth disease. It can therefore be suggested that the two classical types of Charcot-Marie-Tooth syndrome possess variants which are associated with intention tremor. This association is well-known for the hypertrophic type; our report gives an example of the non-hypertrophic type.

Anterior horn cell disease seen in South India

Thirty-two patients with clinical evidence of anterior horn cell dysfunction are descirbed. This group of patients could be divided into those with bulbar dysfunction, and those without. Eighth cranial nerve involvement was seen in 10%. The commonest perpheral distribution seen was symmetrical involvement of all four extremities. During the period of follow-up (1 to 5 years) none of the patients without bulbar dysfunction initially developed such symptoms. In all these patients electromyographic evidence of anterior horn cell disease was confirmed. The motor nerve conduction velocities in all of these patients were normal. None of them showed signs of pyramidal tract involvement. Muscle biopsy showed evidence of group fibre atrophy in 10 cases, was normal in 3, and showed a myopathic pattern in 1. Sural nerve biopsy obtained in a single patient was considered histologically normal. Plasma citrate and plasma pyruvate levels obtained in 5 patients of this group, showed elevated values for plasma citrate with normal plasma pyruvate levels. Conspicuous absence of pyramidal signs, elevated plasma citrate, normal plasma pyruvate values and the extremely slow progression suggest that this group of patients are different from other varieties of anterior horn cell dysfunction previously described.

Fibre function and perception during cutaneous nerve block

In awake human subjects, neural responses in radial nerves to electrical stimulation were recorded with intrafascicular tungsten microelectrodes. Changes in the activity of individual fibre groups during blocking procedures were recorded and correlated with simultaneous alterations in the perception of standardized stimuli. Light touch sensibility in hairy skin appeared to depend on the integrity of A-beta-gamma fibres, cold and pinprick on A-delta fibres, and warmth and dull pain on C fibres.

Motor nerve conduction velocity in peroneal muscular atrophy: evidence for genetic heterogeneity

Measurements of motor nerve conduction velocity are reported in 88 subjects from 20 families in which a clinical diagnosis of peroneal muscular atrophy had been made in the index cases. The values display a bimodal distribution. The majority of cases show a substantially reduced conduction velocity, a smaller group displaying velocities within the normal range or only slightly decreased. This difference was demonstrated to have a genetic basis.

Chronic generalized spinal muscular atrophy of infancy and childhood. Arrested Werdnig-Hoffman disease

Recent studies have shown that the acute fatal form of infantile spinal muscular atrophy (acute Werdnig-Hoffmann disease or spinal muscular atrophy Type I) is a distinct genetic and clinical entity. This has prompted clinical re-examination of the disease known as `arrested Werdnig-Hoffmann disease' which hitherto was thought to be a spectrum variant of the acute fatal form. A total of 18 such patients with the chronic generalized form of spinal muscular atrophy has been known to The Hospital for Sick Children over the past 10 years. Patients with this characteristic clinical syndrome comprise approximately one-fifth of children with chronic spinal muscular atrophy. Clinically, no patient was even able to crawl normally or progress further with motor milestones. Median age of clinical onset is 6 months of age, and life expectancy ranges from 2 years to the third decade. Inevitable spinal and joint deformities occur by the second decade of life. Management should be based on vigorous antibiotic therapy, orthopaedic and neurological surveillance, and a carefully planned educational programme aimed at realistic employment in late adolescence.

Observations on the sensory nature of the intramuscular nerve action potential

The nature and the origin of the small pre-potential wave which can be recorded immediately before the main muscle action potential on indirect stimulation was studied in the median nerve of 12 normal subjects. It is considered to be a sensory antidromic response recorded from the large afferent fibres which innervate the thumb because it was recorded in all 12 subjects, and the threshold was always below the motor threshold. An antidromic response was recorded with stimulating electrodes at the thumb and recording electrodes at the palm. Both antidromic and orthodromic responses were recorded with stimulating electrodes at the palm. The amplitude of the pre-potential was higher at the recording point closest to the sensory fibres for the thumb and progressively decreased with distance in the other points.

The nosology of the spinal muscular atrophies

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Human flexor reflexes

One type of flexor reflex, that recorded from the tibialis anterior muscle in response to electrical stimulation of the sole of the foot, was studied in normal subjects and patients with several neurological disorders. Normally this reflex consists of two components, the second of which is related to the actual withdrawal. The first component, normally of lower threshold, is difficult to evoke in patients with chronic spinal cord or discrete cerebral lesions, whereas it has an unusually low threshold and is very clearly seen in those with Parkinson's disease. In patients with spinal cord disease, the exaggerated flexor reflexes are seen at long latencies after relatively small stimuli. During the early phase of recovery from spinal transection, both components may be seen and are, therefore, spinal in origin. Studies of patients with the sensory neuropathy of Friedreich's ataxia suggest that the afferent fibres responsible for these flexor reflexes are the small myelinated fibres. Recovery curves demonstrate very long-lasting changes in flexor reflex excitability in normal subjects and patients with `spasticity' from spinal lesions. This differs in patients with `spasticity' from lesions rostral to the brain-stem. Examples in man of such physiological phenomena as reciprocal inhibition, local sign, habituation, temporal and spatial summation are discussed.