Kalb and Solomon point out that astronauts traveling to Mars will live in the absence of gravity for more than a year en route. Here they discuss the effects of spaceflight on nervous system function. They emphasize the neuromuscular and vestibular systems because the success of a Mars mission will depend on their proper function. Roberta L. Bondar, MD, PhD, the first neurologist in space, provides editorial perspective.
Kumar reviews our present knowledge of superficial siderosis of the central nervous system resulting from hemosiderin deposition in the subpial layers of the brain and spinal cord. This comprehensive review discusses the role of multimodality imaging in evaluating superficial siderosis and the therapeutic implications of identified associations.
Lee et al confirmed the association between Alzheimer disease and variant alleles in SORL1 in an urban, multiethnic, community-based population. Using a nested case-control analysis in a population-based, prospective study, they found novel single nucleotide polymorphism and haplotype associations, suggesting that there may be extensive allelic heterogeneity in SORL1. Broad regions of the SORL1 gene will need to be scrutinized for functional pathogenic variants.
Pascual et al describe neuroglycopenia as a specific syndrome caused by insufficient glucose availability during brain development. They demonstrate in this elegant and precise study that when neuroglycopenia occurs in the developing brain, thalamic and cortical metabolism mature aberrantly, causing epilepsy associated with other characteristic neurological and behavioral disturbances.
Leira and colleagues indicate that familiarity and comfort with the administration of recombinant tissue plasminogen activator (rtPA) among nonneurologist physicians in a rural setting is still relatively low. However, the improvement in use of rtPA between 1997 and 2003 is encouraging. It is suggested that acceptance of rtPA in rural areas can be further improved with educational campaigns.
Visser et al indicate in this study that patients with primary muscular atrophy have a relentlessly progressive disease course. Patients with a low vital capacity at baseline and a sharp decline of vital capacity during the first 6 months have a poor prognosis. Median survival duration after initial weakness was 56 months.
Murphy and colleagues identified the nature and prevalence of cognitive and behavioral abnormalities in patients with amyotrophic lateral sclerosis (ALS). They find that a sizable proportion of patients with ALS possess a range of behavioral and cognitive changes (Figure). Right hemisphere atrophy may be a biomarker for cognitive impairment in patients with ALS.
The distribution of dementia status and subthreshold abnormalities in 23 patients with amyotrophic lateral sclerosis in an unselected amyotrophic lateral sclerosis sample. FTLD indicates frontotemporal lobar dementia.
Liscic et al point out that a proportion of patients who meet criteria for Alzheimer disease (AD) have frontotemporal lobar degeneration (FTLD) confirmed at autopsy with or without concomitant AD. Thus, the clinical phenotypes of the two disorders may overlap. They studied the clinical and psychometric indicators that distinguish AD from FTLD at initial presentation. Clinical and cognitive features of FTLD may overlap with AD, although behavioral and language difficulties distinguish those with FTLD.
DeKosky and colleagues quantified brain tissue levels of soluble amyloid β (Aβ) peptides and their precursor protein (APP) in relation to Aβ plaque formation after traumatic brain injury (TBI) in humans. They report that plaque-positive TBI patients had higher levels of soluble Aβ1-42 but not Aβ1-40. Thus, selective increases in soluble Aβ1-42 after TBI may predispose individuals with brain injury to develop AD pathology.
Hara et al describe the clinical features of 4 multiplex families with multiple system atrophy (MSA), including clinical genetic features. Previously, MSA had been considered a sporadic disease. Their families indicate that MSA can be inherited as an autosomal recessive disorder.
Hudson and colleagues defined the molecular basis of autosomal dominant progressive external ophthalmoplegia and parkinsonism in a large family with a dominantly transmitted multiple mitochondrial DNA deletion disorder. They found 3 novel heterozygous polymerase γ substitutions in the same family. They indicate in this clinical and molecular genetic study that both autosomal dominant progressive external ophthalmoplegia and parkinsonism can be caused by mutations that directly affect the polymerase domain of the enzyme.
Ribaï et al performed a long-term prospective follow-up of neurological, cardiological, and oculomotor function in a large cohort of patients with Friedreich ataxia. Eighty-eight of 104 patients were treated with the coenzyme Q10 analogue idebenone (5 mg/kg per day). Idebenone treatment did not slow neurological deterioration. Cardiac hypertrophy decreased under treatment, but cardiac function did not improve.
Luchsinger and colleagues indicate that type 2 diabetes is an important risk factor for Alzheimer disease. They hypothesized that diabetes would also be related to a higher risk of mild cognitive impairment, a transitional stage between normal cognition and Alzheimer disease. They report that indeed diabetes was related to a significantly higher risk of all-cause mild cognitive impairment and amnestic mild cognitive impairment.
Hancock et al studied associations between Parkinson disease (PD) and putatively protective factors—smoking, caffeine, and nonsteroidal anti-inflammatory drugs. They report that inverse associations of smoking and caffeine were corroborated using families with PD, thus emphasizing smoking and caffeine as important covariates to consider in genetic studies of PD.
This Month in Archives of Neurology. Arch Neurol. 2007;64(4):476-477. doi:10.1001/archneur.64.4.476