When, where, and how the corpus callosum changes in MCI and AD: a multimodal MRI study

BACKGROUND

The corpus callosum (CC) has been shown to be susceptible to atrophy in Alzheimer disease (AD) as a correlate of wallerian degeneration or retrogenesis. However, when and where these 2 mechanisms intervene is still unclear.

METHODS

In 3 memory clinics, we recruited 38 patients with amnestic mild cognitive impairment (MCI), 38 patients with mild AD, and 40 healthy controls (HC). Combining voxel-based morphometry and diffusion tensor imaging, we investigated CC white matter (WM) density and fractional anisotropy (FA), radial diffusivity (DR), and axial diffusivity (DA).

RESULTS

Compared with HC, patients with amnestic MCI showed reduced WM density in the anterior CC subregion; however, FA, DR, and DA did not differ between the 2 groups. Significant changes were found in patients with mild AD compared with HC in the anterior and posterior CC regions. These differences were evident in both voxel-based morphometry and diffusion tensor imaging analyses. Specifically, we found reduced callosal WM density in the genu, posterior body, and splenium; decreased FA and increased DR in the anterior CC subregion; and increased DA, with no difference in the FA, in the posterior CC subregion.

CONCLUSIONS

Callosal changes are already present in patients with amnestic mild cognitive impairment (MCI) and mild Alzheimer disease (AD). The precocious involvement of the anterior callosal subregion in amnestic MCI extends to posterior regions in mild AD. Two different mechanisms might contribute to the white matter changes in mild AD: wallerian degeneration in posterior subregions of the corpus callosum (suggested by increased axial diffusivity without fractional anisotropy modifications) and a retrogenesis process in the anterior callosal subregions (suggested by increased radial diffusivity without axial diffusivity modifications).

Devic's neuromyelitis optica and mitochondrial DNA mutation: a case report

Cases are described with Leber's optic atrophy and neurological symptoms and/or MRI lesions suggestive of multiple sclerosis. We describe a case of a young woman with Devic's neuromyelitis optica and 3460 homoplasmic mitochondrial DNA mutation.

Prevalence of headache in an elderly population: attack frequency, disability, and use of medication

OBJECTIVES

To assess the 1 year prevalence of tension-type headache (TTH), migraine headache (MH), and chronic daily headache (CDH), as well as of headache in general in a rural elderly population.

METHODS

A door to door two phase survey was carried out on all elderly (>/=65 years) residents in three villages in central Italy. Participants completed a standardised headache questionnaire and underwent a clinical evaluation by a neurologist. Headache diagnosis was made according to the classification of the International Headache Society, with minor modifications for the classification of patients with MH with>/=15 attacks/month.

RESULTS

Eight hundred and thirty three (72.6%) of the 1147 eligible persons completed the study protocol. One year prevalence rates were respectively 44.5% for TTH, 11.0% for MH, 2.2% for symptomatic headaches, and 0.7% for the remaining types of headache. The prevalence of headache in general was 51.0% because 62 residents had both TTH and MH attacks. Prevalence rates of patients with headache were higher in women than men (62.1% and 36.6% respectively) and decreased steadily with age for the 65-74, 75-84, and 85-96 age groups (56.7%, 45.2% and 26.1% respectively). Prevalence rates were 20.4% for patients with moderate to severe attacks, 18.0% for those with >/=1 attacks a month, and 4.4% for those with CDH. Of the 425 with headache 52 (12.2%) had not taken any drugs for their attacks in the previous year, 195 (45.9%) had taken them regularly, and 178 (41.9%) had taken them only when the headache pain interfered with activities that could not be postponed. Medication overuse was reported by 37.8% of patients with CDH with higher proportions for transformed migraine than for patients with chronic TTH (69.2% and 23.8% respectively, p=0.009)

CONCLUSIONS

A consistent proportion of elderly people have primary headaches and consultation with a specialist is particularly recommended for patients with moderate or severe attacks, or with CDH.

Prevalence, awareness, treatment and control of hypertension in the elderly: results from a population survey

Prevalence, awareness, treatment and control of hypertension were assessed in 1032 (90%) of 1147 elderly (> or = 65 years) inhabitants of three Italian villages. Blood pressure (BP) was measured at home on two separate occasions following a standardised protocol. Persons taking antihypertensive drugs or with BP values > or = 140/90 mm Hg were considered as affected by hypertension. Prevalence of hypertension was 64.8%, with higher rates in women than men, and in those aged 75-84 than in those aged 65-74. Diabetes, strokes and hypercholesterolaemia were more frequent in hypertensive than normotensive people, whereas cardiac diseases, overweight and smoking did not differ significantly between hypertensive and normotensive people. Of the 669 hypertensive patients, 439 (65.6%) were aware of their hypertension, 398 (59.5%) were being treated, and 70 (10.5%) had their hypertension controlled. Of the 230 unaware patients, 201 (87.4%) had had their BP measured in the previous year. Of these, 174 (86.6%) had stage 1 hypertension, while 27 had stage 2 hypertension with SBP values <170 mm Hg. Overall, the patients with stage 1 hypertension accounted for 68.3% of the untreated and 50.5% of the treated patients. The use of a single drug was more frequent in patients with controlled (97.1%) or stage 1 (97.0%) than with stages 2-3 (18.9%) hypertension. The drugs prescribed most were angiotensin-converting enzyme (ACE) inhibitors (45%), followed by diuretics (43%). As our findings suggest that BP values can be effectively reduced by treating or increasing drug treatment in stage 1 hypertensive patients, data on safety and effectiveness of this policy are urgently needed. Journal of Human Hypertension (2000) 14, 825-830

Quantitative magnetic resonance analysis in vascular dementia

The potential role of magnetic resonance imaging (MRI) in differentiating between specific causes of cognitive decline in patients with vascular dementia (VD) has not yet been fully established. We therefore decided to assess the supratentorial cerebral contents in 24 patients with a diagnosis of probable VD and in 24 normal subjects, matched for age and education level, using MRI volumetric parameters obtained by means of a quantitative method. The volumes of subarachnoid and ventricular spaces, cerebral tissue, and hyperintense areas on T2-weighted images were calculated. In order to reduce interindividual variability caused by differences in intracranial size, each absolute measurement was normalized to the relative size of the intracranial volume. In addition, we calculated the ratio between the areas of the corpus callosum (CC) and supratentorial brain at the same level on the T1-weighted image midsagittal plane. The MRI data were correlated with the deterioration of cognitive functions. Patients with VD showed significantly lower cerebral tissue volume and CC area, and higher ventricular space volume than normal subjects. Furthermore, the total volume of the T2 signal alterations was higher in VD patients than in normal subjects. In VD patients, this volume was found to be proportional to the increase in the volume of the ventricular space. On the other hand, no correlation was found between the volume of the T2 signal alterations and the area of the CC. The degree of global cognitive dysfunction and the score of each neuropsychological test did not show any correlation with the MRI data. Our results suggest that ventricular enlargement in VD patients is correlated with the increase in volume of the T2 signal abnormalities, but that the degree of global cognitive dysfunction is not influenced by the volume of these T2 signal abnormalities. Furthermore, the CC atrophy does not influence the score of any neuropsychological test or the degree of global cognitive dysfunction.

Stroke, disability, and dementia: results of a population survey

BACKGROUND AND PURPOSE

Stroke, disability, and dementia often coexist in elderly people. We assessed the prevalence and mutual association of these disorders in an elderly rural population.

METHODS

We carried out a door-to-door survey on all subjects aged 65 years or over (n=1032) living in a rural community. To evaluate the associations between stroke and disability and between stroke and dementia, we compared stroke patients with all stroke-free subjects by means of two multiple logistic regression analyses. Subsequently, we performed a case-control analysis by comparing each stroke patient with two age- and sex-matched population control subjects.

RESULTS

We identified 80 stroke patients. After the exclusion of five incident cases, the prevalence of stroke was 7.3% (95% confidence interval [CI], 5.7 to 8.9). Sixty-five percent of stroke survivors and 23% of stroke-free subjects were disabled (age- and sex-adjusted odds ratio [OR], 6.3; 95% CI, 3.7 to 10.9). Thirty percent of stroke survivors and 5.7% of stroke-free subjects were demented. The OR for dementia (stroke patients versus all stroke-free subjects) was 5.8 (95% CI, 3.1 to 10.8) and became 3.4 (95% CI, 1.5 to 8.0) in the case-control analysis.

CONCLUSIONS

In our population, the prevalence of stroke was higher than in previous studies. Stroke survivors were more disabled and more at risk for dementia than stroke-free subjects.

Prevalence of dementia in an elderly rural population: effects of age, sex, and education

OBJECTIVES

To estimate the prevalence of dementia in an elderly rural population and to determine the effects of age, sex, and education.

METHODS

To obtain prevalence estimates of both cognitive impairment and dementia a door to door two phase population survey was carried out in three rural villages in central Italy. Of 1147 inhabitants older than 64, 968 (84.4%) completed the protocol.

RESULTS

The prevalence rates (cases per 100 population over 64) were 8.0 for dementia and 27.3 for cognitive impairment. The prevalence rate for dementia did not differ between men and women (7.9 v 8.2), but increased with age (from 1.1 at age 65-69 to 34.8 at age 90-96). Subjects with less than three years of schooling had a significantly higher prevalence of dementia (14.6; 95% confidence interval (95% CI) 10.2-19.1) than subjects with three or more years of schooling (5.9; 95% CI 4.2-7.7). At the multivariate logistic analysis, the risk related with a low level of education was still present after adjustment for age and sex (OR = 2.0; 95% CI 1.2-3.3). Alzheimer's disease was diagnosed in 64% of the 78 demented patients, vascular dementia in 27%, and other dementing diseases in 9%.

CONCLUSIONS

In both Alzheimer and vascular dementia subtypes, the prevalence rates did not differ between men and women, but increased with age and were higher in subjects with a low level of education.