# Towards a Machine Learning Model for Detection of Dementia Using Lifestyle Parameters
## 2 Materials and Method
### Work Plan
#### 2.3.3 Shortlisting Parameters  
We use statistical methods and domain wisdom to shortlist relevant parameters for the study. The nature of parameters is ordinal; hence, we use [PERSON]'s correlation, which is especially suited for ordinal data [25]. [PERSON]'s correlation can be expressed as following formula:  
\[\text{p}=1-((6{\sum}(\text{d}_{i})^{2})/\text{n}(\text{n}^{2}-1))\]  
where:  
p = [PERSON]'s rank correlation coefficient. d\({}_{i}\) = difference between the two ranks of each observation  
n = number of observations  
**Using domain wisdom** \begin{table}
\begin{tabular}{l l l} \hline \hline
**Parameter** & **Description** & **Possible Values** \\ \hline hc9 disescn9 & person has dementia & dementia—(1, 7), \\  & & No dementia—(2), \\  & & \(-1\) for no data \\ \hline cg9 reascano1 & the person cannot complete tests due & dementia—(1), \\  & to dementia & No dementia—(others) \(-1\) \\  & & Empty for no data \\ \hline cp9 dad8 dem & the person reported dementia in the & dementia—(1), \\  & previous round & No dementia—(\(-1\)) \\  & & Empty for no data \\ \hline is9 reasnprx1 & the person is using a proxy due to & dementia—(1), \\  & dementia & No dementia—(others) \(-1\) \\  & & Empty for no data \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Label Parameters. Based on the medical literature, we have shortlisted parameters based on domain wisdom. They include parameters such as the impact of social relationships [26], spirituality and religion [27], or quality of relationships [28]. Literature surveys of dementia indicate a major role of community and family in the onset of dementia. We have explored literature concerning the relationship between diabetes and dementia [29]. Based on the above literature, we have mapped/identified relevant parameters from NHATS data and shortlisted them in Table 6.  
We also add one more parameter that is not indicated in any literature to correlate with dementia, 'te9 cellphone', just to investigate whether we could discover a parameter that may have an impact on dementia but hasn't been marked as such. This is purely based on an intuition that the operation of technical gadgets involves some amount of cognitive exercise and keeps people connected to their social networks. **Using Statistical Method**  
We calculate the [PERSON]'s correlation of parameters with the label parameter _flag_dem_. Table 7 shows the results and a few of the top correlated elements. \begin{table}
\begin{tabular}{l l l} \hline \hline
**Parameter** & **Description** & **Possible Values** \\ \hline cm9 knowwell & The community knows each other & 1—AGREE A LITTLE 2—AGREE A LITTLE 3—DO NOT AGREE \\ \hline cm9 willnghlp & The community is willing to help & 1—AGREE A LITTLE 3—DO NOT AGREE \\ \hline cm9 peopletrstd & The community can be trusted & 1—AGREE A LITTLE 3—DO NOT AGREE \\ \hline sn9 dnumsn & Total people that the subject trusts & Number of people \\ \hline hh9 dmarstat & Marital status & 1—Yes, 2—No, 3—Separated \\ \hline cs9 dnumchild & Number of children & Number of children \\ \hline hc9 disescn6 & Has diabetes & 1—Yes, 2—No \\ \hline hc9 disescn8 & Had stroke & 1—Yes, 2—No \\ \hline hc9 depresan1 & Little interest or pleasure & 1—NOT AT ALL, 2—SEVERAL  DAYS, 3—MORE THAN HALF THE DAYS, 4—NEARLY EVERY DAY \\ \hline Cg9 memcom1 yr & Any memory issues since last year & 1—MUCH BETTER, 3—SAME, 4—WORSE, 5—MUCH WORSE \\ \hline pa9 attrelser & Attends religions services & 1—Yes, 2—No \\ \hline pa9 imprelser & How important is it to attend religious services & 1—Very Important, 2—Some What  Important, 3—Not So Important \\ \hline wb9 agrwstmt1 & Are others making decisions on behalf of the subject & 1—Agree A Lot, 2—Agree a little, 3—Agree not at all \\ \hline pa9 outfrenjy & Enjoys an outing with friends & 1—Yes, 2—No \\ \hline te9 cellphone & Use of cell phone & 1—Yes, 2—No \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Domain Parameters. **Using Temporal Analysis**  
NHATS data consists of 10 rounds of interview questions.