Mitochondrial encephalomyopathies: a correlation between neuropathological findings and defects in mitochondrial DNA.

Neuropathological studies were carried out in two patients with mitochondrial encephalomyopathies in whom the underlying lesions in muscle mitochondrial DNA (mtDNA) and respiratory enzyme complexes have been investigated. The first, a man with Kearns-Sayre syndrome, died at the age of 49 years. Autopsy showed an old parietal lobe infarct, diffuse spongiform leukoencephalopathy of cerebral and cerebellar white matter and mild spongiform change in deep grey matter and brainstem nuclei. Heteroplasmy of skeletal muscle mitochondrial DNA with a 3.5 kb mtDNA deletion in one of two mtDNA populations was found. The second case, a woman, suffering from myoclonic epilepsy, cerebellar ataxia, bilateral sensorineural deafness, several 'stroke-like' episodes died at age 52. At autopsy, an old infarct was seen in the L internal capsule. Severe loss of neurons and gliosis were found in the dentate nuclei, moderate changes in the red nuclei and inferior olivary nuclei and mild changes in the substantial nigra and locus coeruleus. In both patients, skeletal muscle biopsy showed numbers of ragged-red fibres and intramitochondrial paracrystalline inclusions at electron microscopy. A defect in the synthesis of the ND5 subunit of the respiratory complex I was suggested in the second patient in whom a diagnosis of MELAS was made.

Progression from MERRF to MELAS phenotype in a patient with combined respiratory complex I and IV deficiencies.

Identical twins developed myoclonic epilepsy in their teens. One twin remained mildly affected but the other went on to develop sensorineural deafness and ataxia with lactic acidosis and ragged red fibres leading to a diagnosis of mitochondrial encephalopathy. Multiple stroke-like episodes with hemiparesis followed, indicating progression from a MERRF to a MELAS phenotype. Biochemical studies revealed a severe deficiency of mitochondrial NADH-ubiquinone reductase and a moderate deficiency of cytochrome aa3. Western immunoblotting experiments using polyclonal antibodies raised against human placental cytochrome oxidase identified a similar profile of bands to those seen in controls, supporting the view that cytochrome aa3 deficiency in this case may be a secondary consequence of a failure of assembly related to a severe proximal respiratory chain defect.

Preservation of acquired music performance functions with a dominant hemisphere lesion: a case report.

This paper presents evidence of preservation of acquired music performance functions in a right-handed man with a large dominant hemisphere lesion. Results of music testing, speech pathology testing, neuropsychological testing and neurological examination are presented, with evidence of intact music skills (melodic perception and an ability to read at sight) being compared with lost skills (auditory processing span of 3 digits forward, and impairment of complex rhythmic tasks). Interpretations are offered in light of contemporary theories suggesting that brain processes for musical memory involve different cerebral systems to those for verbal memory.

Chronic pain syndromes in the elderly.

In this paper the painful syndromes of temporal arteritis, polymyalgla rheumatica, glaucoma, trigeminal neuralgia, post-herpetic neuralgia, and temporomandibular joint dysfunction have been described. These conditions occur commonly in the elderly. The dangers of blindness occurring in temporal arteritis or polymyalgia rheumatica, the importance of early diagnosis in glaucomatous headache, the value of Tegretol in trigeminal neuralgia, the paucity of therapeutic agents in post-herpetic neuralgia and the value of dental treatment in tempor-mandibular joint dysfunction have been stressed.

Parkinson's disease.

The classical clinical picture of Parkinson's disease is all too frequently encountered in the elderly patient. The modern classification of causes of Parkinson's disease lists 'idiopathic', and 'post-encephalitic forms', the latter being uncommon in this community.

Abnormal brain scan with subacute extradural haematomas.

Four patients are described with proven subacute extradural haematomas, each with an abnormal cerebral scan of diagnostic assistance. A possible mechanism of production of the subacute extradural haematoma is discussed, and appears to be similar to the mechanism involved in the subacute subdural haematoma. The means by which the abnormal scan results in such cases is also examined, from which it appears that non-specific meningeal membrane inflammatory reaction surrounding the haematoma is significant.