Sigla

The challenge of diagnosing dementia

Every 3 seconds a person is diagnosed with dementia, leading to nearly 10 million new cases of dementia worldwide each year. Alzheimer’s Disease is the most common form of dementia and contributes to 60–70% of cases. Dementia with Lewy bodies comes 2nd, constituting 10-15% of all cases. Lewy body dementias are often difficult to distinguish from Alzheimer’s Disease in the early stages due to overlapping symptoms. Lewy body dementia patients are in many cases initially misdiagnosed as Alzheimer disease, Parkinson's disease or as a psychiatric disorder and tend to have numerous visits to many doctors before getting an accurate diagnosis.

For doctors, one of the concerns is that antipsychotic drugs, which can help Alzheimer’s patients, may have life- threatening side effects for Lewy body dementia patients. Mentis Cura’s Sigla can distinguish Lewy body dementias from other types of dementia with high accuracy.

The diagnoses of dementia and other causes of cognitive impairment are based on clinical signs and symptoms in addition to biological markers for those diseases. Doctors follow national or international guidelines when diagnosing dementia. Some of the methods in current use have the disadvantages of high cost (e.g. PET, SPECT) or being invasive (e.g. CSF). Sigla offers a simple, cost-effective, and non-invasive tool that complements existing protocols by combining a standard 5-minute EEG and statistical pattern analysis.

Our solution - Sigla

Sigla is an advanced and effective diagnostic aid for dementia that offers valuable support for dementia specialist making their diagnosis.

The pathologies of different types of dementia can vary greatly, but they all affect the electrophysiology of the brain, which is reflected directly in the EEG recording (electroencephalogram). Sigla analyses specific patterns in a patient’s EEG that indicate possible dementia and can help differentiate between Lewy body dementia and other types of dementia.

Sigla uses standard EEG recordings for the diagnosis and differentiation of dementia. Sigla is a user friendly software that produces results with high accuracy in a simple report within minutes, detailing two critical perspectives: The Dementia Index that helps clinicians confirm dementia and the Lewy body Index that differentiates Lewy body dementias from other types of dementia.

Sigla is a CE marked class 1 medical device and has been in routine clinical use since 2012.

Dementia Index

The Dementia Index indicates whether an individual’s EEG signals resemble those of individuals suffering from dementia.

A score ranging from 53 - 100 is consistent with EEG signals from individuals with a clinical diagnosis of dementia and constitutes a positive result. If the score ranges from 0 – 47, the EEG signals resemble those of an individual with normal cognition and the score constitutes a negative result. A score ranging from 48 – 52 is inconclusive. The Dementia Index is able to separate patients with a diagnosis of dementia from healthy controls with a sensitivity of 77% and a specificity of 92%, meaning that of those receiving a positive result, 77% truly do have dementia and of those receiving a negative score, 92% truly do not have dementia. The positive likelihood ratio (LR+) is 10, meaning that a patient with a positive score on the Dementia index is 10 times more likely to have dementia than having normal cognition. In the validation cohort, the score on the dementia index was conclusive in 83% of cases.

The Dementia Index should not be used as a standalone test for diagnosing dementia.

Lewy Body Index

The Lewy Body Index indicates whether an individual’s EEG signals resemble those of individuals suffering from Lewy body dementias and should be used to rule out or confirm Lewy body dementia.

Any score ranging from 53 - 100 is consistent with EEG signals from individuals suffering from Lewy body dementia. A score ranging from 0 – 47 is consistent with EEG signals from individuals suffering from other types of dementia. A score ranging from 48 – 52 is inconclusive. The sensitivity of the test is 94%, meaning that of those receiving a positive score, 94% truly do suffer from Lewy body dementia. The specificity of the test is 84%, meaning that of those receiving a negative score (0 – 47), 84% truly do not suffer from Lewy body dementia. The positive likelihood ratio (LR+) is 6, meaning that a patient with a positive score on the Lewy Body Index is 6 times more likely to have Lewy body dementia than having another type of dementia. In the validation cohort, the score on the Lewy Body Index was conclusive in 80% of cases.