White matter hyperintensities rather than lacunar infarcts are associated with depressive symptoms in older people: the LADIS study

White matter changes in dementia: does radiology matter?

White matter changes are frequently seen on MRI in elderly patients. The significance of these changes is still debated. The origin of white matter changes is heterogeneous but the majority are due to arteriosclerosis in brain vessels. The clinical consequence of the presence of white matter changes in relation to dementia is still unclear. Lately, however, many studies have found a relation between the presence and the degree of white matter changes and cognitive dysfunction. This is most obvious in vascular dementia, but has also been suggested to be of importance in Alzheimer's disease. In this review we discuss the background of these changes and the clinical consequences of them in relation to cognitive disorders.

White matter lesions as a predictor of depression in the elderly: the 3C-Dijon study

BACKGROUND

There is increasing evidence for a link between cerebrovascular disease and depression in the elderly but the mechanisms are still unknown. This study examines the longitudinal relationship between depression and white matter lesions (WML) in a sample of elderly aged 65 years and older.

METHODS

Three City (3C)-Dijon is a 4-year follow-up population-based prospective study of 1658 subjects. At baseline, lifetime major depressive episode diagnosis was established using the Mini International Neuropsychiatric Interview. At each study wave, severity of depressive symptoms was assessed using Center for Epidemiological Studies-Depression (CES-D), and antidepressants intake was recorded. At baseline, lifetime major depression (LMD) was defined as lifetime major depressive episode or antidepressant medication intake. At follow-up, subjects were classified "incident depression" if scoring high at CES-D or antidepressant users. At baseline, cerebral magnetic resonance imaging (MRI) was performed to quantify WML volumes using an automated method of detection. At 4-year follow-up, 1214 subjects had a second MRI.

RESULTS

Cross-sectional analysis showed a significantly higher WML volume in subjects with LMD compared with other subjects. Adjusted longitudinal analysis showed that increase in WML load was significantly higher in subjects with baseline LMD (2.1 cm(3) vs. 1.5 cm(3), p = .004). Among subjects free of depression up to baseline (n = 956), the higher the baseline WML volume, the higher the risk of developing depression during follow-up (odds ratio one quartile increase: 1.3; 95% confidence interval: = 1.1-1.7).

CONCLUSIONS

Our data show that depression and WML volumes are strongly related. These results are consistent with the hypothesis of a vascular depression in the elderly.

Behavioural and psychological symptoms are not related to white matter hyperintensities and medial temporal lobe atrophy in Alzheimer's disease

BACKGROUND

The neuropathology of behavioural and psychological symptoms is much less understood than the neuropathology of cognitive impairment in AD. On MRI, medial temporal lobe atrophy (MTA) is presumed to reflect Alzheimer- type pathology. White matter hyperintensities (WMH) are considered markers of vascular pathology.

AIM

We investigated differences in prevalence of behavioural and psychological symptoms in AD according to the presence of MTA and WMH on MRI.

METHODS

Behavioural and psychological symptoms of 111 consecutive AD patients were assessed using the Neuropsychatric Inventory (NPI). Symptoms were considered present when the score was > or =1. On MRI, MTA was rated using the five-point Scheltens-scale and WMH using the four-point Fazekas-scale. Both MRI measures were dichotomised (MTA: absent 0/1, present 2-4; WMH absent 0/1, present 2/3).

RESULTS

Of the 111 AD patients, 60(55%) had MTA, and 32(29%) had WMH. The presence of MTA was associated with the presence of WMH (chi (2) = 11.8, p < 0.001). The prevalence of behavioural and psychological symptoms--defined as a NPI score of > or =1 on at least one symptom--was 74%.The median NPI score of the total study population was 6(0-41). There was no difference in prevalence according to MTA (p = 0.53) or WMH (p = 0.18). On inspection of individual NPI items, neither MTA, nor WMH was related to any of the symptoms.

CONCLUSIONS

There were no differences in prevalence of behavioural and psychological symptoms according to MTA or WMH, as rated on MRI. This suggests that the occurrence of those symptoms depends on other determinants, such as coping style or genetic make-up.

Regional white matter hyperintensity burden in automated segmentation distinguishes late-life depressed subjects from comparison subjects matched for vascular risk factors

OBJECTIVE

Segmented brain white matter hyperintensities were compared between subjects with late-life depression and age-matched subjects with similar vascular risk factor scores. Correlations between neuropsychological performance and whole brain-segmented white matter hyperintensities and white and gray matter volumes were also examined.

METHOD

Eighty-three subjects with late-life depression and 32 comparison subjects underwent physical examination, psychiatric evaluation, neuropsychological testing, vascular risk factor assessment, and brain magnetic resonance imaging (MRI). Automated segmentation methods were used to compare the total brain and regional white matter hyperintensity burden between depressed patients and comparison subjects.

RESULTS

Depressed patients and comparison subjects did not differ in demographic variables, including vascular risk factor, or whole brain-segmented volumes. However, depressed subjects had seven regions of greater white matter hyperintensities located in the following white matter tracts: the superior longitudinal fasciculus, fronto-occipital fasciculus, uncinate fasciculus, extreme capsule, and inferior longitudinal fasciculus. These white matter tracts underlie brain regions associated with cognitive and emotional function. In depressed patients but not comparison subjects, volumes of three of these regions correlated with executive function; whole brain white matter hyperintensities correlated with executive function; whole brain white matter correlated with episodic memory, processing speed, and executive function; and whole brain gray matter correlated with processing speed.

CONCLUSIONS

These findings support the hypothesis that the strategic location of white matter hyperintensities may be critical in late-life depression. Further, the correlation of neuropsychological deficits with the volumes of whole brain white matter hyperintensities and gray and white matter in depressed subjects but not comparison subjects supports the hypothesis of an interaction between these structural brain components and depressed status.

Current evidence for subjective cognitive impairment (SCI) as the pre-mild cognitive impairment (MCI) stage of subsequently manifest Alzheimer's disease

At the present time, there is increasing recognition and understanding of the mild cognitive impairment (MCI) entity as a stage which is a frequent precursor and harbinger of subsequently manifest Alzheimer's disease (AD) and, perhaps, other related conditions, such as vascular dementia (Gauthieret al., 2006). MCI has been defined in two disparate but generally compatible ways in the current literature (see Reisberget al., 2008 (this issue), for a more complete historical overview of MCI). These two definitional approaches might be termed: (a) the clinical approach to MCI, and (b) the clinical plus psychometric approach to MCI.

Depression and cognition in older adults

PURPOSE OF REVIEW

Recognition that depression is associated with neurocognitive impairment and renewed recent interest in milder forms of cognitive impairment in older people (typified by the concept of mild cognitive impairment) have stimulated researchers to investigate the relationship between depression and cognitive impairment. This review identifies and clarifies recent progress in this rapidly developing research area.

RECENT FINDINGS

Neurocognitive impairment persists in most depressed older people after clinical recovery, and slowed information processing speed and possibly executive dysfunction and vascular risk factors underlie this. Most studies suggest that this neurocognitive impairment in turn leads to increased mild cognitive impairment as well as dementia. White matter disease appears to directly contribute to depression in older people and this worsens over time. Polymorphisms in the serotonin transporter gene may be a key risk factor as well, and depression worsens vascular outcome in peripheral arterial disease.

SUMMARY

Clinicians should be aware that neurocognitive deficits persist and have an adverse effect on outcome, and that vascular risk factors may contribute to these deficits.

Late-life depression, religiosity, cerebrovascular disease, cognitive impairment and attitudes towards death in the elderly: Interpreting the data

Geriatric depression is considered to be a major health problem in the elderly. Passing the age, the speed of mental process is decreasing and personality obtains more mature functioning (better coping) while most of its traits remain stable. Empirical studies have shown that fear of death is most prominent during midlife and not late-life. Neuroimaging studies led to the "vascular depression" hypothesis. Depression was found to be a strong predictive factor leading to stroke, while religiosity seemed to be a 'protective' factor. A possible interpretation of these reports could consider late-life depression to be an early symptomatology of an undergoing vascular disease. Religiosity could be interpreted as absence of depression, and therefore, mainly as absence of vascular lesions. The above have profound implications in the understanding of late-life depression and to the therapeutic design, especially in the primary care setting.

Recent understandings in geriatric affective disorder

PURPOSE OF REVIEW

This article focuses on recent research into depression, bipolar disorder and anxiety in older people.

RECENT FINDINGS

Many physical illnesses are associated with a high prevalence of depression but overall medical burden may largely account for this. The relationship between depression and vascular disease is two way. Frontal brain dysfunction may underlie depression both in cerebrovascular disease and neurodegenerative disorders. Besides antidepressants, psychological treatments, psychosocial interventions and enhanced primary care services are effective. Longer-term outcomes are poor but preventive strategies show promise. Medical and psychiatric comorbidity are also important themes in later-life anxiety and bipolar disorders.

SUMMARY

Improving prognosis is a key concern and more research into novel pharmacological approaches (including vasoprotection), psychological interventions and prevention is needed.

Hippocampal volume is an independent predictor of cognitive performance in CADASIL

Recent evidence suggests that hippocampal changes are present in vascular cognitive impairment but their importance and relationship with ischaemic mechanisms remain controversial. To investigate these issues we performed MRI and cognitive assessment in a large cohort (n=144) of patients with CADASIL, a hereditary small vessel disease and model of pure vascular cognitive impairment. Dementia status was ascribed according to DSM-IV and global cognitive function assessed with the Minimental State Examination (MMSE) and Mattis Dementia Rating Scale (MDRS). Hippocampal volume (HV) correlated with age (r=-0.33, p<0.001), brain volume (r=0.39, p<0.001) and lacunar lesion volume (r=-0.23, p=0.008), but not white matter lesions or microhaemorrhages. HV was reduced in dementia (2272+/-333 mm(3) versus 2642+/-349 mm(3), p<0.001) in the whole cohort and the subgroup progressing to dementia before age 60. HV correlated with MMSE (r=0.30, p<0.001), MDRS (r=0.40, p<0.001) and in a multivariate model predicted cognition independent of typical vascular lesions and whole brain atrophy. These findings strengthen the view that hippocampal atrophy is an important pathway of cognitive impairment in vascular as well as degenerative disease.

White matter changes and late-life depressive symptoms: longitudinal study

BACKGROUND

Evidence from cross-sectional studies suggests a link between cerebral age-related white matter changes and depressive symptoms in older people, although the temporal association remains unclear.

AIMS

To investigate age-related white matter changes on magnetic resonance imaging (MRI) as an independent predictor of depressive symptoms at 1 year after controlling for known confounders.

METHOD

In a pan-European multicentre study of 639 older adults without significant disability, MRI white matter changes and demographic and clinical variables, including cognitive scores, quality of life, disability and depressive symptoms, were assessed at baseline. Clinical assessments were repeated at 1 year.

RESULTS

Using logistic regression analysis, severity of white matter changes was shown to independently and significantly predict depressive symptoms at 1 year after controlling for baseline depressive symptoms, quality of life and worsening disability (P<0.01).

CONCLUSIONS

White matter changes pre-date and are associated with the development of depressive symptoms. This has implications for treatment and prevention of depression in later life.