# QuoCo

The tool developped to help clinicians follow the cognition of their elderly patients, using morphometric measurements of pediatric growth charts.

### Q : What’s the difference between "cognitive state" and "cognitive trajectory"?

A : The "cognitive state" is represented by a single point on the charts without considering its evolution over time. The patient's cognitive state is considered normal if the QuoCo score is plotted above the cutoff zone, or it is suspect if the point is into that grayed zone. The "cognitive trajectory" refers to the line traced between the patient's baseline and its most recent QuoCo score.

### Q : What is an interval?

A : An interval is the zone between two plain lines of two dotted lines at the bottom of the charts. If a point is between two lines, You should compute the equivalent of one interval towards the bottom, relatvely to the closest percentile.

### Q : When is a trajectory considered suspect?

A : A trajectory is suspect when it shows a decline greater than one percentile from the initial measurements, which indicates potential cognitive problems. (See our video tutorial for more information)

### Q : Why do I have to multiply by 1000 to obtain the QuoCo score?

A : It is mainly to get rid of the decimals. A result on 1000 also prevents confusion with other cognitive tests based on 100 such as 3MS.

### Q : My patient has 20 years of education. Why don’t I substract 10 from the real age to obtain the standardized age?

A : The maximum value for the education is fixed at 14 years. You must use 7 years of education to compute the standardized age, even if the real education is higher thatn 14 years. The cognitive charts were built form a large database of normal patients from which the MMSE, age and education have been analyzed. Our analysis showed that the MMSE is not favorably influenced over 14 years of education.

### Q : I don’t have a MMSE baseline for my patient. Can I use QuoCo anyway?

A : Yes. If you have a previous MMSE score where the patient did not have a diagnosis of dementia (Major neurocognitive disorder), you can use it as a reference point for comparison with the actual MMSE. If you only have an actual MMSE score, the grayed zone (cut-off) allows you to interpret the cognitive status of the patient.

### Q : Must we always use the initial point as the baseline?

A : No. It is acceptable to use another point as the baseline. For example, if a patient have a better QuoCo score after the baseline, it would be preferable to use that last one. However, it is not the recommendations from our published study (this notion is currently under investigation by our team).

### Q : The QuoCo score I'm trying to plot does not fit into the charts. Why?

A : You probably tried to use data from a patient that does not the have characteristics included in our analysis. Your patient's age must be between 65 and 95, thus a patient with a standardized age less than 58 years cannot be placed on the QuoCo charts. Did you make sure to take account of the limit of 14 years of education?

### Q : The QuoCo score sets a point above the highest percentile line. What’s happening?

A : Your patient’s result is exceptionally good and is better than the highest percentile obtained from our statistical analysis. Everything is fine.

### Q : The trajectory is rising instead of declining. What does it mean?

A : It means the patient’s tests performances are increasingly getting better than what is normally expected. The patient's trajectory is thus very likely normal.

### Q : The QuoCo score of my patient declined of nearly one interval and is considered as limit. Is it normal or not?

A : Our analyses have shown that the trajectory is likely suspect as soon as one interval is lost. However, the larger is the decline, the more suspicious is the trajectory. When the trajectory goes directly onto the next percentile line, it is theorically still acceptable, but the clinical judgment always prevails.

### Q : The first QuoCo point was in the grayed zone (cutoff), but the patient did not have a major NCD (dementia) at that time. Can I still follow its trajectory?

A : If you are confident that the previous score was normal for this patient, yes. The grayed zone percentiles will help you measure its trajectory.

### Q : Shoud I use the MMSE sub-score from "WORLD backwards" or "100-7"?

A : Les courbes cognitives ont été développées à partir des scores de MMSE avec "MONDE à l'envers".

### Q : Why are the percentile lines getting closer at the bottom of charts?

A : It's because the spaces between the percentile lines have been set to maximize the performance of discriminating between normal decline and the development of a dementia (major neurocognitive disorder). For the lowest percentiles, the acceptable decline is smaller because previous scores are already low.

### Q : Can I use the cognitive charts with the MoCA test?

A : Not yet. For now, only the MMSE has been studied.