Chronic Insomnia and MRI-Measured Hippocampal Volumes: A Pilot Study

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Study Objectives: Morphometric analysis of magnetic resonance imaging brain scans was used to investigate possible neuroanatomic differences between patients with primary insomnia compared to good sleepers.

Design: 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.

Setting: University Hospital Sleep Center and Radiology Department Participants: 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.

Interventions: N/A

Measurements and Results:

  • 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.

    Conclusions: 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

    Source: Sleep. August 1, 2007, volume 30(8) ; pp 955-958,, by Riemann D, Ulrich Voderholzer U, Spiegelhalder K, Hornyak M, Buysse DJ, Nissen C, Hennig J, Perlis ML, van Elst LT, Feige B. Department of Psychiatry and Psychotherapy, Freiburg University Medical Center, Freiburg, Germany; Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; Department of Radiology, Freiburg University Medical Center, Freiburg, Germany; Department of Psychiatry of the University of Rochester, Rochester, New York.

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    4 thoughts on “Chronic Insomnia and MRI-Measured Hippocampal Volumes: A Pilot Study”

    1. pris2000 says:

      I was trained in research methodology and a sample size of 16 isn’t nearly large enough to post here, in my opinion, even as a pilot study. Not only is a larger sample size needed, but replication of the results.

      1. noteworthy says:

        Hi I am not trained and I’m wondering what “sample size” you are referring to and what is a “sample size?”

      2. pris2000 says:

        Sample size is the term used in research for the number of subjects in a study. Imagine the total number of people with this problem. Think of them as tennis balls. Each time you reach into the humungus basket holding them, you get a different handful of tennis balls. Pull out a small number, the odds become lower that they represent the basket as a whole. Also, this is why replication is important. The next handful could show different results. If a number of (good-sized) handfuls are pulled out and the studies show that this trend continues, you’re showing that it’s not just an accident of sampling (picking one odd handful), but a replicable result.

        The fact that the researcher matched the subjects only helps rule out other factors causing the problem, but the sample size still stronly limits the generalization of the results he got.

        I hope he or someone replicates this since it’s an exciting direction to take.

        I hope that makes it clearer.

      3. noteworthy says:

        Thank you so much for replying to my question. You explained very clearly in laymen’s terms and I appreciate that. I feel very good about my pwm comment because I am not trained in research methodology, you are and you ended your reply to me with a statement similar to mine. I also wrote I hope people will continue to follow through with this research. Sleep deprivation is an enormous problem in our society. My own children suffer because of it and I am at my wits end, even though they are adults. Good luck to you.

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