Hirayama K

Cervical dural sac and spinal cord in juvenile muscular atrophy of distal upper extremity

Objective: To investigate specificity and significance of dynamic changes of the cervical dural sac and spinal cord during neck flexion in juvenile muscular atrophy of the distal upper extremity. Background: The disorder affects young people—predominantly men—and is progressive for several years. One autopsy case showed ischemic necrosis of the cervical anterior horn, suggesting that the disorder is a type of cervical myelopathy. Some authors classify it as monomelic amyotrophy, implying that it is a focal motor neuron disease. Methods: Neuroradiologic examinations including myelography, CT myelography, and MRI in a fully flexed neck position were performed on 73 patients with this disorder and on 20 disease control subjects. Results: A distinctive finding in the disorder was forward displacement of the cervical dural sac and compressive flattening of the lower cervical cord during neck flexion. The forward displacement was significantly greater in patients with disease duration less than 10 years than in age-matched control subjects and patients in a late, nonprogressive stage. Conclusions: Radiologic abnormalities of the lower cervical dural sac and spinal cord support the hypothesis that this disorder is a type of cervical myelopathy.

Dopamine D1 receptors in Parkinson's disease and striatonigral degeneration: a positron emission tomography study.

Striatal dopamine D1 receptors were investigated in 11 patients with Parkinsons disease (PD), five patients with striatonigral degeneration (SND) and six age-matched controls by positron emission tomography and carbon-11 labelled SCH23390. The SND patients showed mean 12%, 21%, and 31% declines in the ratios of radioactivity in the caudate, anterior putamen, and posterior putamen compared with that in the occipital cortex. These ratios were not significantly altered in the PD patients. The results may explain the different therapeutic responses to levadopa between SND and PD patients, and this technique might prove useful for their differentiation.

Spinocerebellar degenerations in Japan: a nationwide epidemiological and clinical study

A nationwide survey of patients in Japan with spinocerebellar degenerations (SCD), including SDS and SND, was conducted from 1988 to 1989. The survey consisted of two parts. The first revealed that the estimated total number of patients with SCD in Japan was 5,050 (range: 4,100–6,000) with an estimated prevalence of 4.53 per 100,000 in 1987. The second part investigated the neurological and functional status of patients with SCD. The percentages of those belonging to each subtype of SCD were: OPCA; 34.4%, LCCA; 15.2%, MHCA; 12.6%, HHCA; 7.5%, SDS; 7.0%, HSP; 3.9%, DRPLA; 2.5%, FA; 2.4%, MJD; 2.0% and SND; 1.5%. Compared with European epidemiological studies Japan had a higher proportion of non‐hereditary types of SCD. Various clinical features of SCD subtypes were compared grouped by pathological lesion and heredity. HHCA and LCCA: cerebellar ataxia predominated in all stages, and neurological signs other than cerebellar ataxia were rare. MHCA, DRPLA and MJD: inthe early phase ataxia was the most common symptom in MHCA, the AC form of DRPLA and MJD, but ataxia was less common and chorea or epilepsy were often observed in ME and PH forms of DRPLA. Other frequently observed clinical features were parkinsonian rigidty in MHCA, abnormal movements and posture in DRPLA and MJD, and disturbances of eye movements in MHCA, the AC form of DRPLA and MJD. OPCA, SDS and SND: dominant clinical features were cerebellar ataxia in OPCA, autonomic disturbance in SDS, and parkinsonian rigidity in SND. FA and HSP: both were rare in Japan. Clinical features related to supra‐supinal lesions were frequently observed in FA. Functional status of SCD: the severity of illness was significantly associated with the level of independence in each item of ADL. Activities not requiring dynamic balance were performed independently for a longer period than those requiring dynamic balance. Among SCD subtypes, functional prognosis was poorest in non‐hereditary, multi‐systemic types (OPCA, SDS and SND) followed by hereditary multi‐systemic types (MHCA, DRPLA and MJD), and better in spinal types (FA and HSP) and cerebellar types (HHCA and LCCA).

Nationwide survey of juvenile muscular atrophy of distal upper extremity (Hirayama disease) in Japan

Juvenile muscular atrophy of the distal upper extremity (JMADUE, Hirayama disease) was first reported in 1959 as ‘juvenile muscular atrophy of unilateral upper extremity’. Since then, similar patients in their teens or 20s have been described, under a variety of names, not only in Japan, but also in other Asian countries, as well as Europe and North America. Biomechanical abnormalities associated with JMADUE have recently been reported through various imaging examinations, proposing its disease mechanism. Since JMADUE differs from motor neuron disease, or spinal muscular atrophy, this disease entity should be more widely recognized, and early detection and effective treatments should be considered. We report an epidemiological study in Japan. Two nationwide questionnaire‐based surveys, conducted in Japan from 1996 to 1998, identified 333 cases. The numbers of patients per year, distribution of ages at onset, mode of onset, time lapse between onset and quiescence, neurological signs and symptoms, imaging findings, and the effects of conservative treatments were analyzed. The peak age was 15 to 17 years, with a marked male preponderance, usually a slow onset and progression, and quiescence six or fewer years after onset. There was a predominantly unilateral hand and forearm involvement with ‘cold paresis’. The imaging findings are described.

Prosopagnosia: A Clinical and Anatomical Study of Four Patients

We tested in great detail face perception and face memory in four cases of prosopagnosia. Three of them showed deficits of face perception and/or of familiar faces memory. There was one prosopagnosic patient, however, who showed no abnormality in face perception and discrimination and could recall familiar faces. This case suggests that a form of prosopagnosia may exist, which is due to the disconnection between face perception and face memory. X-ray CT, MRI and PET studies revealed that two patients did not have damage of the left hemisphere, supporting the view that prosopagnosia can arise from unilateral right-sided lesion.

Familial Young-Adult-Onset Arteriosclerotic Leukoencephalopathy with Alopecia and Lumbago without Arterial Hypertension

Here we review a total of 17 patients, including 4 of our own, with young-adult-onset arteriosclerotic leukoencephalopathy, alopecia and lumbago without hypertension. All were Japanese and the illness seemed to be transmitted in an autosomal recessive fashion. The male to female ratio was 7.5:1. The age of onset usually ranged from 25 to 30 years. Acute lumbago, spondylosis deformans, diffuse baldness, and progressive motor and mental deterioration were common clinical features. Cerebral arteriosclerosis and white mater disease were demonstrated pathologically or radiologically. Although the pathogenesis has remained obscure, we think this is a new clinico-pathological entity distinct from the classic type of Binswangers disease.

Detection of benzodiazepine receptor occupancy in the human brain by positron emission tomography

Benzodiazepine receptor occupancy in the brain following oral administration of clonazepam (CZP) with a dose of 30 μg/kg in six healthy young men and a further dose of 50 μg/kg in one of the subjects was estimated by carbon-11 labeled Ro15-1788 and positron emission tomography (PET). The effects of CZP on the latency of auditory event-related potentials (P300) were also studied. Overall brain 11C uptake was depressed and the % inhibition of 11C uptake in the gray matter of the brain at 30 min after [11C]Ro15-1788 injection was 15.3–23.5% (mean, n=6) following 30 μg/kg CZP when compared with that in the control experiment without any previous treatment. The 11C uptake in the cerebral cortex in the subject who received both doses decreased in a dose-related manner after 30 μg/kg and 50 μg/kg CZP. The P300 latency was prolonged significantly by 30 μg/kg CZP [31.6±16.3 ms (mean±SD, n=6), P<0.05]. The P300 latency in the same subject was prolonged in a dose-related manner by 30 μg/kg and 50 μg/kg CZP. The technique using [11C]Ro15-1788 and PET permits comparison of the pharmacological effects with the percentage of receptor sites which benzodiazepines occupy in the human brain. P300 also seems to be useful to investigate the pharmacological effects of benzodiazepines.

Alexia with agraphia of kanji (Japanese morphograms).

The case of the right-handed young Japanese woman with alexia with agraphia of kanji (the Japanese morphograms) due to a small circumscribed haematoma in the left posterior inferior temporal gyrus is described. Her chief complaint was the inability to read and write kanji. Detailed examination showed that her alexia with agraphia was much more predominant for kanji than kana (the Japanese syllabograms). These facts suggest that the processing of kanji and kana involves different intrahemispheric mechanisms.

Juvenile muscular atrophy of distal upper extremity (Hirayama disease): Focal cervical ischemic poliomyelopathy

Hirayama disease is characterized by an initially progressive muscular weakness and atrophy of the distal upper limb(s) in adolescence, occurring predominantly in males, followed by spontaneous arrest within several years. Although the disease could be separated from motor neuron disease, some authors considered the illness to be a variant of degenerative motor neuron disease until the first autopsy case was reported which showed focal ischemic changes in the anterior horn of the lower cervical cord. Since then, many in Japan have recognized the disease as cervical ischemic poliomyelopathy; however, several authors in foreign countries did not or do not appreciate the pathologic findings of the disease, and still consider the illness a degenerative motor neuron disease. The pathology of the disease prompted neuroradiologic investigations, which have revealed dynamic changes of the cervical dural sac and spinal cord induced by neck flexion. The cause of these dynamic changes is unknown. However, as the number of patients is exceedingly large in Japan, there may be an ethnic factor.

Pontine lesion in opsoclonus-myoclonus syndrome shown by MRI.

Two patients with opsoclonus-myoclonus syndrome are reported whose magnetic resonance imaging (MRI) showed brain stem lesions. Both patients developed the opsoclonus-myoclonus syndrome after an upper respiratory illness. One case had visual hallucinations during the course of illness and MRI revealed a focal lesion in the pons involving the junction of basis and tegmentum. MRI of the second case showed a focal lesion at the upper pontine tegmentum.