Longitudinal modeling of frontal cognition in APOE ε4 homozygotes, heterozygotes, and noncarriers.

BACKGROUND: Fibrillar amyloid deposition preferentially affects the frontal lobes, temporal pole/neocortex, and posterior cingulate by age 65 years in APOE ε4 carriers prior to the diagnosis of mild cognitive impairment (MCI) and Alzheimer disease (AD), but is it impairing frontally mediated neuropsychological performance? METHODS: A total of 71 ε4 homozygotes (HMZ), 194 ε4 heterozygotes (HTZ), and 356 ε4 noncarriers (NC) who did not differ significantly in mean age (56.6 years), years of education (15.6), gender (70% women), or follow-up duration (6.3 years) had neuropsychological testing every 2 years including the Auditory Verbal Learning Test (AVLT) and frontal/executive tasks sensitive to psychomotor speed, working memory, problem solving, and activity. A subset also received the Iowa Gambling Task (IGT). Findings were then tested in a clinical sample of 27 patients with incident MCI and AD. RESULTS: APOE ε4 carriers had greater acceleration of decline (quadratic effect) than NC on the AVLT (p = 0.04) but not on any frontal test. APOE ε4 HMZ had greater velocity of decline (linear effects) than NC on all mental arithmetic tests: paced auditory serial attention task (PASAT) 3 second (p = 0.01) and 2 second (p = 0.004) versions; and Wechsler Adult Intelligence Scale-Revised arithmetic (p = 0.048). IGT performance did not differ between 12 ε4 HMZ, 27 ε4 HTZ, and 44 NC. Among 27 patients with incident MCI and AD, the PASAT showed progressive decline preceding diagnosis in 50%. CONCLUSIONS: No frontal cognitive effects were as robust as memory decline. APOE ε4 HMZ declined more quickly than NC on mental arithmetic tests related to frontal lobe-mediated working memory ability.

Cerebrovascular risk factors and preclinical memory decline in healthy APOE ε4 homozygotes.

OBJECTIVE: To characterize the effects of cerebrovascular (CV) risk factors on preclinical memory decline in cognitively normal individuals at 3 levels of genetic risk for Alzheimer disease (AD) based on APOE genotype. METHODS: We performed longitudinal neuropsychological testing on an APOE ε4 enriched cohort, ages 21-97. The long-term memory (LTM) score of the Auditory Verbal Learning Test (AVLT) was the primary outcome measure. Any of 4 CV risk factors (CVany), including hypercholesterolemia (CHOL), prior cigarette use (CIG), diabetes mellitus (DM), and hypertension (HTN), was treated as a dichotomized variable. We estimated the longitudinal effect of age using statistical models that simultaneously modeled the cross-sectional and longitudinal effects of age on AVLT LTM by APOE genotype, CVany, and the interaction between the two. RESULTS: A total of 74 APOE ε4 homozygotes (HMZ), 239 ε4 heterozygotes (HTZ), and 494 ε4 noncarriers were included. APOE ε4 carrier status showed a significant quadratic effect with age-related LTM decline in all models as previously reported. CVany was associated with further longitudinal AVLT LTM decline in APOE ε4 carriers (p=0.02), but had no effect in noncarriers. When ε4 HTZ and HMZ were considered separately, there was a striking effect in HMZ (p<0.001) but not in HTZ. In exploratory analyses, significant deleterious effects were found for CIG (p=0.001), DM (p=0.03), and HTN (p=0.05) in APOE ε4 carriers only that remained significant only for CIG after correction for multiple comparisons. CONCLUSION: CV risk factors influence age-related memory decline in APOE ε4 HMZ.

Clinical and electrodiagnostic findings in copper deficiency myeloneuropathy.

INTRODUCTION: Copper deficiency is an increasingly recognised cause of neurological impairment. This retrospective review highlights clinical and electrodiagnostic findings in patients diagnosed at our institution with copper deficiency. METHODS: Clinical, radiographic and electrodiagnostic findings were reviewed in patients with evidence of copper deficiency. Patients with other potential causes of myelopathy or neuropathy were excluded. RESULTS: The predominant clinical feature in all six patients was a sensory ataxia, resulting in marked gait unsteadiness. Nerve conduction studies and needle EMG were performed in all patients and revealed a mild to moderate distal, axonal, sensorimotor peripheral neuropathy. Median and tibial somatosensory evoked potentials were abnormal in all five patients in which it was performed, showing impaired conduction in central or proximal peripheral somatosensory pathways. CONCLUSIONS: This pattern of electrodiagnostic findings suggests that impairment in somatosensory pathways demonstrated by somatosensory evoked potential testing is the main cause of the sensory ataxia in patients with copper deficiency.

Nonvasculitic autoimmune inflammatory meningoencephalitis imitating Creutzfeldt-Jakob disease.

BACKGROUND: Nonvasculitic autoimmune inflammatory meningoencephalitis and Creutzfeldt-Jakob disease can present as rapidly progressive encephalopathies with similar clinical features. Slowing of background rhythm is an electroencephalographic characteristic shown by both, but persistent periodic sharp waves are more specific for Creutzfeldt-Jakob disease and have not been reported in nonvasculitic autoimmune inflammatory meningoencephalitis or related autoimmune meningoencephalitides. OBJECTIVE: To describe a patient with clinical (rapidly progressive myoclonus, dementia, and Parkinsonism) and electroencephalographic findings (persistent periodic sharp waves) that diagnostically suggest Creutzfeldt-Jakob disease. DESIGN AND SETTING: A case report at the Mayo Clinic Arizona, Scottsdale. RESULTS: The patient made a dramatic recovery with resolution of the periodic sharp wave complexes after treatment with high-dose corticosteroids. Our case is the first reported case of a patient with probable nonvasculitic autoimmune inflammatory meningoencephalitis and electroencephalographic periodic complexes suggestive of Creutzfeldt-Jakob disease. CONCLUSION: Rapidly progressive encephalopathy with periodic sharp wave complexes can be associated with a reversible autoimmune syndrome.