Article

Chronic insomnia and MRI-measured hippocampal volumes: A pilot study

Department of Psychiatry and Psychotherapy, Freiburg University Medical Center, Hauptstr. 5, D-79104 Germany.
Sleep (Impact Factor: 5.06). 09/2007; 30(8):955-8.
Source: PubMed

ABSTRACT Morphometric analysis of magnetic resonance imaging brain scans was used to investigate possible neuroanatomic differences between patients with primary insomnia compared to good sleepers.
MRI images (1.5 Tesla) of the brain were obtained from insomnia patients and good sleepers. MRI scans were analyzed bilaterally by manual morphometry for different brain areas including hippocampus, amygdala, anterior cingulate, orbitofron-tal and dorsolateral prefrontal cortex.
University Hospital Sleep Center and Radiology Department
8 unmedicated physician-referred patients with chronic primary insomnia (3 males, 5 females; 48.4 + 16.3 years) and 8 good sleepers matched for age, sex, body mass index, and education.
N/A.
Patients with primary insomnia demonstrated significantly reduced hippocampal volumes bilaterally compared to the good sleepers. None of the other regions of interest analyzed revealed differences between the 2 groups.
These pilot data raise the possibility that chronic insomnia is associated with alterations in brain structure. Replication of the findings in larger samples is needed to confirm the validity of the data. The integration of structural, neuropsychological, neuroendocrine and polysomnographic studies is necessary to further assess the relationships between insomnia and brain function and structure.

0 Followers
 · 
172 Views
  • Source
    • "The finding that lower levels of self-reported sleep efficiency (i.e., of the time spent in bed, less time is spent actually asleep) was associated with smaller hippocampi is particularly novel, though not surprising given emerging evidence of the critical role of sleep-wake changes to cognition in neurodegenerative disease (see [21]). This finding is also aligned with recent research findings in insomniacs as well as those in healthy older people showing, respectively, that poor sleep is associated with smaller hippocampal volume [35] and spectroscopic markers of glial integrity in the hippocampus [17]. While the precise mechanisms underpinning such relationships are unknown, animal data has shown that sleep is critical for the promotion of neurotrophins and hippocampal neurogenesis, and importantly, that prolonged sleep disruption is associated with substantial (30–80%) decreases in cell proliferation and cell survival to maturation [5]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Background and Objectives: Decreased hippocampal volume in older adults is associated with neurodegenerative and psychiatric diseases. Several modifiable risk factors have been associated with the size of this structure, however the relative contribution of these factors to hippocampal atrophy is unclear. This study aimed to examine the relationship between modifiable risk factors and hippocampal volume in older adults at risk of cognitive decline. Methods: Two hundred and eighteen participants (mean age = 67.3 years, MMSE = 28.6) with mood and/or memory complaints underwent clinical and neuropsychological assessment, and magnetic resonance imaging. Measures of depression, global cognitive functioning, exercise, vascular health, cognitive reserve, sleep, and memory were collected. Hippocampal volumes were derived using image segmentation as implemented by FMRIB Software Library. Results: Smaller hippocampal volumes were strongly associated with poorer verbal learning and memory as well as diagnoses of either multiple or amnestic mild cognitive impairment. Based on univariate correlations, multivariable regressions were performed (controlling for age and total intracranial volume) to determine which modifiable risk factors were associated with hippocampal volume. For the left hippocampus, poor sleep efficiency and greater than five years untreated depressive illness remained a significant predictors. For the right hippocampus, diabetes and low diastolic blood pressure were significant predictors. Conclusions: Although their contribution is small, lower sleep efficiency, low blood pressure, diabetes, and untreated depression are associated with reduced hippocampal volumes. Studies exploring the impact of early intervention for these risk factors on hippocampal integrity are warranted.
    Journal of Alzheimer's disease: JAD 11/2014; DOI:10.3233/JAD-142016 · 4.15 Impact Factor
  • Source
    • "Manual morphometry 20 patients with PI and 15 matched controls No difference in hippocampal size between groups Neylan et al. [37] Manual morphometry Subjective sleep assessment of 17 patients with PTSD and 19 matched controls Worse insomnia correlated with smaller volumes of the CA3 and dentate areas of the hippocampus Altena et al. [33] VBM 24 patients with PI and 13 matched controls No gray matter differences in the area of the hippocampus between groups Riemann et al. [29] "
    [Show abstract] [Hide abstract]
    ABSTRACT: Posttraumatic stress disorder (PTSD) is associated with smaller volumes of the hippocampus, as has been demonstrated by meta-analyses. Proposed mechanistic relationships are reviewed briefly, including the hypothesis that sleep disturbances mediate the effects of PTSD on hippocampal volume. Evidence for this includes findings that insomnia and restricted sleep are associated with changes in hippocampal cell regulation and impairments in cognition. We present results of a new study of 187 subjects in whom neither PTSD nor poor sleep was associated with lower hippocampal volume. We outline a broad research agenda centered on the hypothesis that sleep changes mediate the relationship between PTSD and hippocampal volume.
    Alzheimer's and Dementia 06/2014; 10(3):S146–S154. DOI:10.1016/j.jalz.2014.04.016 · 17.47 Impact Factor
  • Source
    • "Comparing the magnetic resonance imaging of the brain of patients with primary insomnia with that of good sleepers showed bilateral reductions in hippocampal volumes [149]. Another study was able to confirm these findings [150] and the impaired memory functions of insomniacs have been related to these findings [150e154]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Sleep is a complex physiological process and still remains one of the great mysteries of science. Over the past 10 y, genetic research has provided a new avenue to address the regulation and function of sleep. Gene loci that contribute quantitatively to sleep characteristics and variability have already been identified. However, up to now, a genetic basis has been established only for a few sleep disorders. Little is yet known about the genetic background of insomnia, one of the most common sleep disorders. According to the conceptualisation of the 3P model of insomnia, predisposing, precipitating and perpetuating factors contribute to the development and maintenance of insomnia. Growing evidence from studies of predisposing factors suggests a certain degree of heritability for insomnia and for a reactivity of sleep patterns to stressful events, explaining the emergence of insomnia in response to stressful life events. While a genetic susceptibility may modulate the impact of stress on the brain, this finding does not provide us with a complete understanding of the capacity of stress to produce long-lasting perturbations of brain and behaviour. Epigenetic gene-environment interactions have been identified just recently and may provide a more complex understanding of the genetic control of sleep and its disorders. It was recently hypothesised that stress-response-related brain plasticity might be epigenetically controlled and, moreover, several epigenetic mechanisms have been assumed to be involved in the regulation of sleep. Hence, it might be postulated that insomnia may be influenced by an epigenetic control process of both sleep mechanisms and stress-response-related gene-environment interactions having an impact on brain plasticity. This paper reviews the evidence for the genetic basis of insomnia and recent theories about epigenetic mechanisms involved in both sleep regulation and brain-stress response, leading to the hypothesis of an involvement of epigenetic mechanisms in the development and maintenance of insomnia.
    Sleep Medicine Reviews 08/2013; DOI:10.1016/j.smrv.2013.05.002 · 9.14 Impact Factor
Show more