Brainstem auditory evoked response in adrenoleukodystrophy

Auditory brainstem response and audiologic findings in adrenoleukodystrophy: its variant and carrier

Auditory brain stem response, auditory sensitivity, speech discrimination function, acoustic reflex threshold, and reflex decay were studied in seven children with adrenoleukodystrophy (ALD), nine adults with adrenomyeloneuropathy (AMN), one child with neonatal ALD, and two carriers of ALD. Significant auditory dysfunctions were found in only two patients; a retrocochlear type auditory disorder in one child with ALD, and a profound deafness in a child with neonatal ALD. None of the patients showed significant abnormality in acoustic reflex threshold and reflex decay except for one patient with ALD who showed a slightly elevated reflex threshold. All but two ALD patients showed significantly prolonged wave latencies and interwave intervals. The latency values revealed the highest incidence of abnormality in the I to III interval; this was followed by the III to V interval, then by wave I. Significantly, one child with asymptomatic ALD and both heterozygous female relatives showed abnormal ABRs, demonstrating the high sensitivity of ABR in detection of the existence of pathophysiological condition in subclinical or presymptomatic ALD.

Multimodal evoked potential studies in leukodystrophies of children

Evoked potentials were studied in 22 children with leukodystrophy [10 metachromatic leukodystrophy (MLD), 4 Pelizaeus-Merzbacher (PM), 3 Krabbes, 2 adrenoleukodystrophy (ALD), and one each of Alexander's, Canavan's and multiple sulphatase deficiency (MSD) diseases]. The ABRs were abnormal in all patients (except for the younger ALD), but varied with the type of leukodystrophy. The PM and Krabbes patients had abnormal ABRs with a loss of the rostral waves, accompanied in Krabbes with delayed I-III interpeak latencies; in MLD, ALD and MSD prolonged interpeak latencies were found. Three patients who had no clinical signs, but were positively diagnosed as MLD on the basis of absent arylsulphatase A, also had abnormal ABRs. The SEPs were abnormal in all patients. Cortical SEPs were absent in 16 and abnormal in 5 who were in the earlier stages of their disease. Cervical SEPs were within normal limits except for the Krabbes and MLD patients studied, who showed peripheral slowing. The VEPs were normal in only 6 and, unlike the ARBs and SEPs, did not seem to covary with clinical severity across the various leukodystrophies but did correlate with disease progression. Thus, multimodal EPs are useful in the diagnostic differentiation of the leukodystrophies.

Adrenoleukodystrophy: frequency of presentation as a psychiatric disorder

Adrenoleukodystrophy (ALD) is an inheritable clinical disorder in which very long chain fatty acids accumulate in several tissue types. ALD is underrepresented in the psychiatric literature, although the disorder may cause an organic brain syndrome, often misdiagnosed as another psychiatric problem. A survey of 109 reported cases of ALD revealed that 39% presented with some psychiatric sign or symptom, whereas 17% presented exclusively as a psychiatric problem. A computed axial tomogram (CAT) head scan is recommended to rule out ALD in psychiatric patients suspected of having organic brain disease, as a characteristic image may be found in ALD patients who have brain involvement.

The inherited neurodegenerative disorders of childhood: clinical assessment

This review represents an examination of four groups of neurodegenerative diseases, namely the sphingolipidoses, the adrenoleukodystrophy complex, the neuronal ceroid lipofuscinoses, and the sialidoses/sialuria complex. Using a combination of clinical assessment, neuroradiologic appearance, and clinical neurophysiology, one may develop strategies that lead to specific chemical or biochemical determinations for specific diagnoses. In general, disorders of white matter may be distinguished from disorders of gray matter by their appearance on computed tomography and by abnormalities of nerve conduction velocities and auditory brain stem responses. In contrast, disorders of gray matter may be distinguished from disorders of white matter by their appearance on computed tomography and utilization of electroretinography, visual evoked responses, and, to a lesser extent, EEG findings. Where necessary, skin, conjunctival, or nerve biopsy may prove to be useful adjuncts to the diagnosis. Presently, treatment depends on prevention, although aggressive efforts are under way to establish corrective therapy by enzyme replacement. To this end, the use of already existing animal models may prove to be helpful.

Myopathy in an infant with a fatal peroxisomal disorder

An infant with neonatal adrenoleukodystrophy experienced extreme hypotonia and virtually continuous convulsions at four months of age and died. Light and electron microscopic examination revealed evidence of myopathy and the presence of mitochondrial inclusions. Concentrations of very long-chain fatty acids were elevated in blood and fibroblasts and the oxidation of 14C-labeled fatty acids was defective. Urinary pipecolic acid content was increased. Activity of the peroxisomal dihydroxyacetone phosphate acyltransferase, which catalyzes the first step in plasmalogen synthesis, was decreased.

Electrophysiologic studies in neonatal adrenoleukodystrophy

Recent electrophysiologic studies have focussed attention on the X-linked adrenoleukodystrophy (ALD) and its myeloneuropathic variant. No organized studies are, however, yet available on its relatively recently described neonatal variant. We conducted electroencephalographic, electroretinographic and evoked response studies in 2 patients with neonatal ALD. In one patient, an infant, initial EEG, hypsarrhythmic in waking and somewhat periodic in sleep, showed dramatic improvement on ACTH therapy accompanied with a seizure-free status. The EEG and clinical improvement, however, were temporary. No improvement occurred following pyridoxine therapy. Her electroretinogram (ERG), visual evoked responses (VERs) and far-field short latency brain-stem auditory evoked responses were also abnormal. The latter studies probably reflected photoreceptor degeneration, optic nerve involvement, cochlear and/or auditory nerve involvement respectively in neonatal ALD. The other patient, a 3.5-year-old girl, also had an EEG characterized by a moderate- to high-amplitude slow background activity and high-amplitude multifocal, generalized or periodic paroxysmal discharges, but presence of some better formed theta frequencies in background activity precluded a hypsarrhythmic label on her EEG. Her ERGs and VERs were totally extinct but in contrast to the first patient, she had clear-cut optic atrophy and retinitis pigmentosa on ophthalmological examination.

Neurophysiological studies in adrenomyeloneuropathy. A report on five cases

Neurophysiological studies were performed in 5 patients in two families suffering from adrenomyeloneuropathy (AMN). The diagnosis was supported by electron microscopy of nerve twigs in all cases and by the demonstration in 2 cases of increased levels of saturated very long chain fatty acids in cultured fibroblasts (Moser, personal communication). Measurements of the sensory-motor conduction velocities demonstrated the variability of the peripheral nerve damage in AMN, further confirmed by quantitative studies of sensory nerve biopsies. Somatosensory evoked potentials (SEP) were abnormally delayed and their configuration was abnormal, mainly following stimuli applied to the lower limbs. Our data suggest a more severe involvement of the fasciculus gracilis and an extension of the lesions to the medial lemnisci in agreement with the few postmortem reports showing multifocal demyelination. Brain stem auditory evoked potentials (BAEP) were delayed, pointing towards lesions between cochlear nerve and superior olivary nucleus and also at lateral lemniscal level. Morphological confirmation is lacking but the close topographical relationship between the secondary auditory pathways and the medial lemnisci indicates that even small lesions could damage simultaneously both pathways. Neurophysiological studies contribute to the diagnosis of AMN, they confirm the inter- and intrafamilial variability of the clinical features and help to explain the signs and symptoms of this condition.

Brain stem auditory, visual and somatosensory evoked potentials in leukodystrophies

Brain stem auditory (BAERs), visual (VEPs) and somatosensory evoked responses (SEPs) were recorded in 12 patients with Pelizaeus-Merzbacher leukodystrophy (PMD), three with adrenoleukodystrophy (ALD) and three with metachromatic leukodystrophy (MLD). All the 3 evoked responses were abnormal in all patients except normal VEPs and SEPs in a patient with early ALD. In most patients wave I with and without wave II were the only components of the BAERs that remained, subsequent components (waves III-VII) were absent. VEPs were severely altered; either no identifiable response to flash or pattern reversal stimuli could be recorded or the major components were significantly delayed in latency. Short latency SEPs following median nerve stimulation usually showed a normally recorded Erb's potential (N10), but an absence or marked attenuation of cervical (N14) and early scalp components (N19 and P22) or the occurrence of the scalp components with a significant delay. Multimodality evoked responses provide more information regarding the functional integrity of several afferent systems in patients with white matter disorders.

Adrenomyeloneuropathy. A report on two families

Adrenomyeloneuropathy (AMN) is reported in two kindreds. In the first family, four male patients were affected: two adults with the full clinical picture but with a different chronology of the main symptoms, a third adult with central nervous system involvement and a child who died early with adrenal insufficiency. The second family included two male patients with AMN, one adult with raised ACTH levels and his nephew with normal adrenal function. Two other young males died with adrenoleukodystrophy (ALD), one being subjected to a postmortem study. Clinical, endocrinological, neurophysiological and pathological studies were performed. The following conclusions can be made (1) AMN and ALD are closely related entities; (2) there exists a considerable intrafamilial variability of the clinical picture; (3) AMN is to be included in the differential diagnosis of myelopathies and, conversely, signs of central nervous system damage must be sought in males patients with adrenal insufficiency; (4) electron microscopy of nerve twigs brings supportive diagnostic evidence pending the more widespread determination of the C26/C22 fatty acids ratios in cultured fibroblasts or plasma.

Brainstem auditory evoked responses in spinocerebellar degeneration and Wilson disease

Brainstem auditory evoked responses (BAERs) were studied in 30 healthy subjects, 20 patients with spinocerebellar degeneration (SCD), and 6 patients with Wilson's disease. In addition to the standard 8 click per second stimulation rate, increased stimulation frequency was applied which identified wave V for its stability under different stimulation rates. No prolongation of wave latencies was noted in SCD patients, irrespective of clinical features, except in 1 patient who had a latency slightly above the normal range. Wilson disease with neurological symptoms produced prolongation of wave latencies in every case, whereas the patients without neurological involvement showed a normal BAER pattern.