If you watched Kim Kardashian’s latest health update and felt a jolt at the phrase “holes on the brain”, you were not alone. It is a term that sounds catastrophic. Yet on the type of scan she had, a hole does not mean missing tissue. It signals a region working at a lower level because it is receiving less blood and oxygen, often due to age, stress or other long-term influences. That distinction matters. True holes look very different and usually arise from severe disease.

In footage from her reality show The Kardashians, her doctor points out “holes” on a brain scan, describing them as areas of “low activity”. These were found on a single-photon emission tomography, or Spect, scan, which uses a small dose of radioactive tracer and a specialised camera to show how well different parts of the brain are functioning. Around the same time she was also diagnosed with a brain aneurysm, discovered during an MRI scan. The aneurysm is a structural weakness in a blood vessel and is unrelated to the low-activity patches seen on Spect.

These “holes” or “dents” are actually a normal part of brain ageing and can appear in people in their early forties. They do not appear in everyone, but they are a common feature of midlife scans and reflect reduced blood flow in small, localised areas. In typical ageing the brain loses about five percent of its volume each decade, even without any disease.

Lower activity on Spect can arise for many reasons. Chronic stress, for example, has been shown to cause macroscopic changes in the brain, including changes in the connections........

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