What is the role of the hippocampus in memory?

Many factors can contribute to memory ability, such as environmental factors, genetics, cardiovascular disease, mood, age, among others. Hippocampal volume has also been reported to play a critical role in verbal memory function (1). A correlation has been shown between hippocampal volume and severity of cognitive impairment (2).

How do you assess the “health” of the hippocampus? What is the role of an MRI scan?

Our neural networks are complex and much remains unknown about the connections involved in brain functions and disease states. Volumetric measurements are one way to study and shed light on these complex neural networks. Measuring the volume of various parts of the brain is possible with an MRI scan.

What role does BrainKey play in assessing the hippocampus?

BrainKey makes it easy to assess the volume of the hippocampus, among other areas of the brain.

Why is hippocampal volume important?

Measurement of hippocampal volume can be useful to diagnose and track progression in several brain disorders such as Alzheimer's disease. Hippocampal volume was found to be reduced in patients by 25% in Alzheimer's disease, 21% in mixed dementia, 11% in vascular dementia, and 5% in normal pressure hydrocephalus when compared to control patients.

The severity of dementia increased as hippocampal volume decreased. This suggests that measurement of hippocampal volume can help differentiate different types of dementia and follow disease progression (2).

Atrophy or thinning of the hippocampus can be seen in early stages of cognitive impairment and Alzheimer’s disease (3). Left hippocampal volume can predict verbal memory performance (4). It appears that hippocampal size is weakly correlated with initial retrieval. There seems to be a stronger correlation of hippocampal size to memory retrieval after several weeks (1).

Hippocampal volume has also been studied in mood disorders. Along with volumetric changes in other parts of the brain, studies show that some patients who suffer from depression have smaller hippocampal volume (5). There are also findings of lower hippocampal volume in patients prior to the development of depression (6). Epilepsy is another disorder in which the size of the hippocampus has been studied extensively. Adults with temporal lobe epilepsy and a history of febrile seizures tend to have significantly reduced hippocampal volume (7).

When a patient gets their hippocampal volume results, what do you recommend they do with this?

The ability of BrainKey’s software to assess the volume of brain structures like the hippocampus is exciting. It is important to discuss the findings of your brain MRI and the information provided by BrainKey’s software with your healthcare provider for a complete picture of your brain health.

Can patients improve their hippocampal volume? Do you have any recommendations on how they can do this?

Aerobic exercise has been shown to preserve left hippocampal volume (8). A healthy diet, including the consumption of fresh vegetables, fruit, and grilled fish, can also preserve hippocampal volume and maintain memory function (9). Spatial exploration and learning new skills using brain games and even 3D video games are being found to have a positive impact on hippocampal volume (10).

References

1. K. B. Walhovd, A. M. Fjell, I. Reinvang, A. Lundervold, B. Fischl, B. T. Quinn, A. M. Dale. Size does matter in the long run. Hippocampal and cortical volume predict recall across weeks. Neurology Oct 2004, 63 (7) 1193-1197
2. Vijayakumar, A., & Vijayakumar, A. (2012). Comparison of hippocampal volume in dementia subtypes. ISRN radiology, 2013, 174524. https://doi.org/10.5402/2013/174524
3. Nobis L, Manohar S, Smith S, Alfaro-Almagro F, Jenkinson M, Mackay C, Husain M. Hippocampal volume across age: Nomograms derived from over 19,700 people in UK Biobank, NeuroImage: Clinical, Volume 23,2019.
4. de Flores R, La Joie R, Chételat G. Structural imaging of hippocampal subfields in healthy aging and Alzheimer’s disease. Neuroscience, Volume 309, 2015, 29-50.
5. Schmaal L., Veltman D.J., Van Erp T., Sämann P., Frodl T., Jahanshad N., Loehrer E., Tiemeier H., Hofman A. Subcortical brain alterations in major depressive disorder: Findings from the ENIGMA Major Depressive Disorder working group. Mol. Psychiatry. 2016;21:806–812. doi: 10.1038/mp.2015.69.
6. Rao U., Chen L.-A., Bidesi A. S., Shad M. U., Thomas M. A., Hammen C. L. (2010). Hippocampal changes associated with early-life adversity and vulnerability to depression. Biol. Psychiatry 67, 357–364. 10.1016/j.biopsych.2009.10.017
7. Barr WB, Ashtari M, Schaul NBilateral reductions in hippocampal volume in adults with epilepsy and a history of febrile seizures. Journal of Neurology, Neurosurgery & Psychiatry 1997;63:461-467.
8. Firth J, Stubbs B, Vancampfort D, Schuch F, Lagopoulos J, Rosenbaum S, Ward P, Effect of aerobic exercise on hippocampal volume in humans: A systematic review and meta-analysis, NeuroImage, Volume 166, 2018, 230-238.
9. Akbaraly T, Sexton C, Zsoldos E, Mahmood A, Filippini N, Kerleau C, Verdier J, Virtanen M, Gabelle A, Ebmeier K, Kivimaki M. Association of Long-Term Diet Quality with Hippocampal Volume: Longitudinal Cohort Study, The American Journal of Medicine, Volume 131, Issue 11, 2018, 1372-1381.
10. Clemenson Gregory D., Henningfield Caden M., Stark Craig E. L. Improving Hippocampal Memory Through the Experience of a Rich Minecraft Environment. Frontiers in Behavioral Neuroscience, volume 13, 2019, 57.
    
    
    
    

Dr. Dhira Khosla is a board-certified neurologist with years of experience caring for her patients. For the past few years, she has been involved with healthcare start-ups in various capacities including clinical development and business strategy. She approaches medtech innovations through a patient- and provider-focused lens in order to bring solutions that are meaningful to the clinical decision-making process as well as overall patient quality of life.