The most common temporal lobe pathology is Ammons Horn sclerosis (AHS), and several different imaging techniques have been utilized to detect this with varying success. We describe the clinical application of magnetic resonance imaging (MRI) using a three-dimensional volume technique which allows total hippocampal volume to be measured and symmetry evaluated. Hippocampal surface area was calculated in sequential 1.5 mm thick contiguous images, using a GE IC workstation. Total volumes and surface areas were calculated. The cross-sectional surface area at 1.5 mm intervals was displayed graphically, permitting morphometric analysis of the hippocampus throughout its length. Focal atrophy within any part of the hippocampal formation (HF) and its extent could thus be assessed. Patients with well-lateralized temporal lobe epilepsy (TLE) (n = 20) and well-defined frontal lobe epilepsy (FLE) (n = 20) were studied, and volumes compared with normal values derived from 10 neurologically normal controls. Asymmetric hippocampal volume loss was demonstrated in all 20 patients with clinically typed TLE, but not in normal controls or patients with FLE. Volume loss distribution was anterior in 12 patients, posterior in one patient and widespread in seven patients. Secondarily generalized seizures were strongly associated with widespread loss. This method of surface area and volumetric analysis of the hippocampus in TLE can demonstrate asymmetry and focal involvement, and help distinguish between hippocampal and frontal pathologies.

The authors propose that together with other radiologic features of progressive supranuclear palsy (PSP) such as midbrain atrophy, a visual assessment of the superior cerebellar peduncle may help increase the clinical diagnostic accuracy in PSP.

Quantitative MRI combining HCT2 and HCVR is a reliable method for diagnosing hippocampal sclerosis noninvasively. End-folium sclerosis and amygdala sclerosis should be considered in patients with intractable TLE and negative findings on MRI studies, including quantitative measures of the hippocampus.

Late-onset progressive myelopathy, years after odontoid fracture, is considered a rarity. Sixteen patients with diagnosis of their odontoid fractures delayed from four months to 45 years have been studied and treated. Three had forgotten about the injury and, in the rest, the significance had been minimized by their clinicians. Fifteen patients had characteristic C-2 nerve root pain and 10 had noted weak hands and walking difficulties. Fifteen patients had Type II fractures, which were mobile in 11; hypertrophic pseudoarthrosis was marked in two. In seven patients it was confirmed at surgery that all or part of the transverse ligament was interposed in the fracture. Transoral surgery, combined with a variety of posterior fusion techniques, has allowed cord decompression, an understanding of the pathomechanics, and sound posterior bone fusion with arrest of the myelopathic condition. Measurements of craniovertebral angles and cord cross-sectional area in this series revealed a rough correlation, but the most striking relationship was between length of delay in diagnosis and diminished cord area in both non-union and malunion, suggesting a progressive injury mechanism. It is proposed that late myelopathy following odontoid fracture may be more common than hitherto believed and should be considered in the evaluation of patients with cervical spondylosis. The condition may be progressive. Finally, non-union may be due to interposition of the transverse ligament.

High definition computed cervical myelograms have been made in flexion and extension in 13 patients with Morquio-Brailsford's disease. We observed that: 1) odontoid dysplasia was present in every case, with a hypoplastic dens and a detached distal portion which was not always ossified; 2) atlanto-axial instability was mild, and anterior atlanto-axial subluxation was absent in most cases; 3) severe spinal cord compression, when present, was due to anterior extradural soft-tissue thickening; 4) this compression was not relieved by flexing or extending the neck and was manifested early in life; 5) posterior occipitocervical fusion resulted in disappearance of the soft-tissue thickening and normalisation of subsequent development of the dens. We conclude that the severity of neurological involvement at the craniovertebral junction was determined by soft-tissue changes, not by the type of odontoid dysplasia nor by subluxation. Posterior occipitocervical fusion proved to be an effective treatment.

Our data also suggest that HAM occurs more frequently among HTLV-I-infected subjects than reported by previous studies. The HTLV-II infected myelopathy patient identified in this cohort, together with three other case reports in the literature, implies a pathogenic role for this human retrovirus. The diagnosis of HTLV-associated myelopathy should be considered in cases of spastic paraparesis or neurogenic bladder when risk factors for HTLV-I or HTLV-II infection are present.

Sixteen affected individuals are described from two families with early onset autosomal dominant familial Alzheimer's disease. A mutation at codon 139 in the presenilin 1 gene on chromosome 14 results in a methionine to valine substitution which cosegregates with the disease in these families. Onset of dementia was before the age of 50 years in all individuals. The ages at onset within each family were tightly clustered but were significantly different between the families; this difference could not be accounted for by apolipoprotein E status and suggests the existence of a further genetic factor that modifies age at disease onset. The pattern of cognitive decline was similar in both families: early memory loss (initially selective for verbal memory in some individuals) was followed soon after by loss of arithmetic skills while naming and object perception skills were relatively preserved. A speech production deficit was observed in three members of one family but not in the other. Seizures were common and usually predated by myoclonic jerks by a number of years. Serial MRIs showed progressive cortical atrophy with periventricular white matter change appearing 3-4 years into the disease. PET revealed parieto-temporal hypometabolism in all individuals scanned. The diagnosis of Alzheimer's disease was confirmed with typical histopathology in one individual from each family.

The neuroanatomic or neuropathologic basis of Gilles de la Tourette's syndrome (GTS) remains unknown. Recent studies have suggested abnormalities of cerebral asymmetry and basal ganglia volumes. We studied 17 patients with GTS and eight normal controls using volumetric MRI techniques for measuring the caudate nucleus, amygdala, and corpus callosum. One subject with GTS was subsequently excluded because he was left handed. No absolute differences in caudate nucleus volumes between patient and control groups were evident. There was an increase in corpus callosum (CC) cross-sectional area and a loss of the normal asymmetry of the caudate nucleus in the patient group. A loss of the normal correlation between cross-sectional area of the CC and whole brain index (WBI) in the patient group also was found. The amygdala measurements had a poor interrater reliability.