Some patients who come to the memory clinic today, they come with cognitive complaints. They tell us, “Hey doc, my memory is not what it used to be, I’m not happy with my memory functioning”. “My memory is a catastrophe”, sometimes this is what they tell you. “It’s a catastrophe. I forget everything.” You carry out cognitive assessment, neuropsychological battery and they score within normal limits...
Some patients who come to the memory clinic today, they come with cognitive complaints. They tell us, “Hey doc, my memory is not what it used to be, I’m not happy with my memory functioning”. “My memory is a catastrophe”, sometimes this is what they tell you. “It’s a catastrophe. I forget everything.” You carry out cognitive assessment, neuropsychological battery and they score within normal limits. So we call them subjective cognitive decline. The traditional approach to these patients in memory clinics is to tell them “You’re fine, there’s nothing wrong with it, go home, be happy”. Because in the current armamentarium, there are no secondary prevention interventions to put in place. But these patients, they go home but they’re not happy with our answer because they they’re still concerned, they are still worried. These are the first patients that we can start from to develop secondary prevention.
These patients with subjective cognitive decline there’s no taxonomy today. What is a taxonomy? Taxonomy is a breakdown into diseases. It’s like dementia. We have a taxonomy of dementia. We know that dementia can be Alzheimer’s disease, can be frontotemporal, can be Lewy body, can be a number of other conditions. We even have a taxonomy for MCI. We know that there’s MCI due to Alzheimer’s disease, there’s MCI associated with Parkinson’s disease, there is MCI even in frontotemporal dementia, and so on and so forth. So we have a taxonomy. We don’t have a taxonomy for SCD. Although, there’s different causes for persons to have complaints and be cognitively unimpaired. And we have identified at least three groups, three large subgroups. One is patients with some psychological or psychiatric background. And I’m not talking about a diagnosis of schizophrenia or bipolar disorder. I’m talking about something much more subtle. Patients with depressive and anxiety symptoms or personality features, not necessarily diagnosed personality disorder, but some specific personality features such as conscientiousness, or obsessive-compulsive traits, not obsessive-compulsive disorders, but obsessive-compulsive traits. This is one group of patients. The other group of patients of SCDs is those who have either physical comorbidity, a huge load of physical comorbidity, or neurological conditions, or a previous stroke or epilepsy, or multiple sclerosis… This is a second group. And then there’s a third group, which is the SCD patients where you cannot identify any plausible reason for their complaint. And it turns out that this group is the one which is at higher risk for developing dementia, for developing a real cognitive impairment in the coming years.
