Small hippocampus associated with depression in the elderly: Risk factor or shrinkage?

ScienceDaily (July 22, 2011) — Imaging studies have repeatedly found that people with depression have smaller hippocampal volumes than healthy individuals. The hippocampus is a brain region involved in learning and memory, spatial navigation, and the evaluation of complex life situations or "contexts." However, because in prior studies hippocampal volume was only measured in people once they became depressed, it has been unclear whether a small hippocampus renders a person vulnerable to developing depression, or whether it is a consequence of depression.

A new study published in Biological Psychiatry has approached that problem by following a large population of elderly individuals over a 10 year period.

Researchers performed an initial imaging scan on subjects to obtain a baseline measurement of their hippocampal volume and then performed follow-up scans 5 and 10 years later. During this time, they also repeatedly assessed the individuals for both depressive symptoms and depressive disorders.

Corresponding author Dr. Tom den Heijer explains their findings: "We found that persons with a smaller hippocampus were not at higher risk to develop depression. In contrast, those with depression declined in volume over time. Our study therefore suggests that a small hippocampal volume in depressed patients is more likely an effect of the depression rather than a cause."

"The principal importance of this type of research is that it may provide insight into age-related impairments in the function of the hippocampus," reflected Dr. John Krystal, Editor of Biological Psychiatry. "For example, in Alzheimer's disease, memory problems and disorientation are prominent symptoms, reflecting among other things the impaired function of the hippocampus."

Future studies will be needed to better understand whether current treatments protect the hippocampus and hippocampal function.

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by Elsevier, via AlphaGalileo.

Journal Reference:

Tom den Heijer, Henning Tiemeier, Hendrika J. Luijendijk, Fedde van der Lijn, Peter J. Koudstaal, Albert Hofman, Monique M.B. Breteler. A Study of the Bidirectional Association Between Hippocampal Volume on Magnetic Resonance Imaging and Depression in the Elderly. Biological Psychiatry, 2011; 70 (2): 191 DOI: 10.1016/j.biopsych.2011.04.014

Note: If no author is given, the source is cited instead.

Disclaimer: This article is not intended to provide medical advice, diagnosis or treatment. Views expressed here do not necessarily reflect those of ScienceDaily or its staff.

View the original article here sciencedaily.com

REM sleep behavior disorder is a risk factor for Parkinson's disease

ScienceDaily (July 29, 2011) — Patients suffering REM sleep behaviour disorders dream nightmares in which they are attacked and pursued, with the particularity that they express them by screaming, crying, punching and kicking while sleeping. Lancet Neurology has published the third consecutive work in five years about the relationship between this disorder and Parkinson's disease.

The first work showed in 2006 that 45% of patients who suffer this sleep disorder develop Parkinson's disease and other neurodegenerative diseases caused by a lack of dopamine in the brain. The second article discovered that neuroimaging tests that measure dopamine in the brain, such as the brain SPECT, are useful to identify patients with REM sleep disorders with increased risk of developing a neurodegenerative diseases such as Parkinson's disease.

The new study applied brain SPECT to conclude that the levels of dopamine in the brain are quickly lowering over the years in patients with REM sleep behaviour disorder. This neuroimaging technique becomes the first tool to detect the disease progression at an early stage. The first author of the three articles is Dr. Àlex Iranzo, doctor from the Neurology Service at the Hospital Clínic of Barcelona, researcher at the Biomedical Research Institute of August Pi i Sunyer (IDIBAPS) and member of the Multidisciplinary Sleep Disorders Unit , and the senior authors were to Dr. Joan Santamaria and Dr. Eduard Tolosa, from the same institution.

The study involved comparing for three years the evolution of brain SPECT in 20 patients with REM disorder and 20 healthy controls. The neuroimaging technique measures the presence of dopamine in the substantia nigra, a part of the brain associated with learning and harmony of body movements. In Parkinson's disease a deficiency of dopamine in the substantia nigra causes tremor, stiffness and movement slowness in patients. Results show that after 3 years of monitoring the production of dopamine in the control group was reduced by 8% due to age, while the group of REM sleep disorder patients experienced a reduction of 20%. Once the 3 year follow-up ended, 3 of 20 patients in the REM sleep disorder group had developed Parkinson's disease and their dopamine reduction was around 30%.

The three works led by the IDIBAPS -- Hospital Clínic of Barcelona team conclude that more efforts are needed to create neuroprotective drugs that prevent the progression from REM sleep behavior disorders to Parkinson's disease. For the first time scientists have a technique, brain SPECT, to evaluate whether these drugs are effective. Authors of the study suggest that, to be considered effective, a neuroprotective drug should significantly prevent the dopamine concentration from dropping in these patients.

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by IDIBAPS - Institut d'Investigacions Biomèdiques August Pi i Sunyer.

Note: If no author is given, the source is cited instead.

Disclaimer: This article is not intended to provide medical advice, diagnosis or treatment. Views expressed here do not necessarily reflect those of ScienceDaily or its staff.

View the original article here

Small hippocampus associated with depression in the elderly: Risk factor or shrinkage?

ScienceDaily (July 22, 2011) — Imaging studies have repeatedly found that people with depression have smaller hippocampal volumes than healthy individuals. The hippocampus is a brain region involved in learning and memory, spatial navigation, and the evaluation of complex life situations or "contexts." However, because in prior studies hippocampal volume was only measured in people once they became depressed, it has been unclear whether a small hippocampus renders a person vulnerable to developing depression, or whether it is a consequence of depression.

A new study published in Biological Psychiatry has approached that problem by following a large population of elderly individuals over a 10 year period.

Researchers performed an initial imaging scan on subjects to obtain a baseline measurement of their hippocampal volume and then performed follow-up scans 5 and 10 years later. During this time, they also repeatedly assessed the individuals for both depressive symptoms and depressive disorders.

Corresponding author Dr. Tom den Heijer explains their findings: "We found that persons with a smaller hippocampus were not at higher risk to develop depression. In contrast, those with depression declined in volume over time. Our study therefore suggests that a small hippocampal volume in depressed patients is more likely an effect of the depression rather than a cause."

"The principal importance of this type of research is that it may provide insight into age-related impairments in the function of the hippocampus," reflected Dr. John Krystal, Editor of Biological Psychiatry. "For example, in Alzheimer's disease, memory problems and disorientation are prominent symptoms, reflecting among other things the impaired function of the hippocampus."

Future studies will be needed to better understand whether current treatments protect the hippocampus and hippocampal function.

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by Elsevier, via AlphaGalileo.

Journal Reference:

Tom den Heijer, Henning Tiemeier, Hendrika J. Luijendijk, Fedde van der Lijn, Peter J. Koudstaal, Albert Hofman, Monique M.B. Breteler. A Study of the Bidirectional Association Between Hippocampal Volume on Magnetic Resonance Imaging and Depression in the Elderly. Biological Psychiatry, 2011; 70 (2): 191 DOI: 10.1016/j.biopsych.2011.04.014

Note: If no author is given, the source is cited instead.

Disclaimer: This article is not intended to provide medical advice, diagnosis or treatment. Views expressed here do not necessarily reflect those of ScienceDaily or its staff.

View the original article here