A large family with paroxysmal ataxia and continuous myokymic discharges is described. The disorder is of autosomal dominant inheritance. During attacks coordination of movements and balance are disturbed; often a postural tremor of the head and the hands and fine twitching in some of the facial and hand muscles are present. The attacks usually last a few minutes and may occur several times per day. They first appear in childhood and tend to abate after early adulthood. The attacks are frequently precipitated by kinesigenic stimuli similar to those in paroxysmal kinesigenic choreoathetosis. Their occurrence can be reduced or prevented by carbonic anhydrase inhibitors. Between attacks a slight postural tremor and ataxia was found in a few of the elderly affected members. Fine rippling myokymia was obvious in a few and could be detected on close inspection in about half of the adults. Electromyography (EMG) showed myokymic discharges in all affected members. The characteristics and reactivity of this myokymic activity suggest multiple impulse generation in the peripheral nerves.

The results of electro-oculographic recordings made after caloric vestibular stimulation (C.O.G.) in severe head injured patients are discussed. It was found that: 1. The C.O.G. correlates with the state of consciousness of the patients. 2. The rate of improvement of the C.O.G. correlates with the rate of the clinical improvement. 3. A prediction of the duration of unconsciousness can be made by repeated C.O.G. scores as well as by repeated scoring of the clinical state. 4. In all patients a paradoxical response is present except in those who have regained clear consciousness and in those persisting in a vegetative state, so the presence of a paradoxical response indicates the possibility of further improvement. It was supposed that in patients with a paradoxical response a functional brain dysfunction was present, which was at least partly caused by disturbed neurotransmitter metabolism. Therapeutic trials with L-DOPA and physostigmine were successful in patients with a paradoxical response, but without any result in those without this phenomenon. The responses to L-DOPA and to physostigmine are related respectively to motor pattern and to verbal or non-verbal communication.

A large kinship with an autosomal he red itary-mot0 r-and-senso ryneuropathy (HMSN) form of Charcot-Marie-Tooth disease (CMTD) is described. The affected members have the clinical features and reduced motor nerve conduction velocities of the hypertrophic type of CMTD, or HMSN 1. Biopsies of the sural nerves of five affected members showed a large variability of demyelination and remyelination and onion bulb formation, independent of axonal atrophy and the severity of the disease. These findings are discussed in relation to recent literature. T h e peroneal form of autosomal dominant inherited motor and sensory neuropathy was divided by Dyck and Lambert13*14 into two major types: a demyelinating hypertrophic form and a neuronal type of Charcot-Marie-Tooth disease (CMTD), which were designated hereditary-motor-andsensory-neuropathy types I and I1 (HMSN I and HMSN 11), respectively. The most obvious differences between these two types are the motor nerve conduction velocities (MNCVs) and the nerve biopsy findings. The MNCVs of all nerves, including those to muscles that are not severely denervated, is markedly reduced in HMSN I and is normal or only slightly reduced in HMSN 11. The nerve biopsies show generally abundant demyelination and remyelination in HMSN I, while such changes are only sparsely present in HMSN 11.

Light and electron microscopic findings from two sural nerve biopsies obtained at a one-year interval from a patient with the clinical features of Seitelberger's disease are described. Ballooned axons with accumulations of membranous profiles, vesicles, mitochondria, and a homogeneous center were present, and there were masses of 90 A filaments in endothelial, endoneurial, perineurial, and Schwann cells. These pathological alterations were less prominent in the second nerve biopsy, which showed a more pronounced decrease in myelinated fibers. The case shows that a generalized increase of 90 A filaments in structures of the peripheral nervous system is not a phenomenon exclusively occurring in patients with giant axonal neuropathy and, furthermore, that it may be a transitory feature.

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