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This article was undertaken to review the history of professional awareness of tardive dyskinesia (TD) and to address reasons for the delay in such recognition. The literature was reviewed, and selections are included to highlight some of the major issues. Personal recollections are deliberately emphasized since they may reflect the phenomenon of personal discovery familiar to others and the now widespread professional awareness of TD. TD is indeed well recognized by psychiatrists and neurologists, and most general practitioners are also aware that the syndrome exists. Physicians were once unfamiliar with the concept of a drug reaction that was so long delayed as is possible with TD, nor did they know that a drug side effect could present in this manner. The historical delay in initial recognition of TD, and the reason for such delay, remain of interest. The lack of a perfect therapy and the uncertainty regarding the precise pathophysiologic basis of TD remain as challenges. Most psychiatrists, and many neurologists, probably have vivid memories of specific patients with TD. This author, a neurologist, was blessed to work with George Crane and other investigators in the early days of TD and was witness to some of the original uncertainty regarding what seemed to be a new phenomenon. TD has reshaped our concepts of disease and our awareness that diseases can originate from deleterious late effects of beneficial agents.

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We have studied 72 members belonging to a large kindred with a hearing disorder inherited in an autosomal dominant pattern. We used audiological, physiological, and psychoacoustic measures to characterize the hearing disorders. The initial phenotypic features of the hearing loss are of an auditory neuropathy (AN) with abnormal auditory nerve and brainstem responses (ABRs) and normal outer hair cell functions [otoacoustic emissions (OAEs) and cochlear microphonics (CMs)]. Psychoacoustic studies revealed profound abnormalities of auditory temporal processes (gap detection, amplitude modulation detection, speech discrimination) and frequency processes (difference limens) beyond that seen in hearing impairment accompanying cochlear sensory disorders. The hearing loss progresses over 10-20 years to also involve outer hair cells, producing a profound sensorineural hearing loss with absent ABRs and OAEs. Affected family members do not have evidence of other cranial or peripheral neuropathies. There was a marked improvement of auditory functions in three affected family members studied after cochlear implantation with return of electrically evoked auditory brainstem responses (EABRs), auditory temporal processes, and speech recognition. These findings are compatible with a distal auditory nerve disorder affecting one or all of the components in the auditory periphery including terminal auditory nerve dendrites, inner hair cells, and the synapses between inner hair cells and auditory nerve. There is relative sparing of auditory ganglion cells and their axons.

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Movement disorders in children often have a genetic basis. An explosion of genetic information in the past decade has led to the discovery of genetic defects in many forms of ataxia, parkinsonism, dystonia, tremor, and spastic paraparesis. This review focuses on genetically defined, early-onset diseases characterized primarily or exclusively by movement disorders. Particular emphasis is placed on disorders for which clinical or research testing is available.

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Three case studies of postvaccinal parkinsonism (PVP) demonstrated signs and symptoms identical to conventional diagnostic standards of idiopathic Parkinson's disease (PD). PVP is a sub-type of acute disseminated encephalomyelitis (ADE) that also includes postinfectious parkinsonism (PIP) and postinfectious encephalomyelitis (PIE). All ADE has a unitary pathology consisting of monophasic perivenous inflammation followed by demyelination compared with PD in which Lewy bodies are present in only 75% of studies. We hypothesize that: (1) The seminal event in PD is latent viral invasion emanating from cranial and dorsal root ganglia. (2) Viruses intermittently invade and damage neuropigmented cells secondary to perivenous demyelination. This may explain the numerous clinical and pathological manifestations of PD. Evidence is presented that this pathoetiology probably accumulates subclinically over a long timespan prior to Levy body formation and presentation of clinical signs. This hypothesis has key features similar to one previously published that will be summarized concerning multiple sclerosis.

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