This app has no internet access and keeps its data in a location secure from other apps, so the only way your data's privacy can be compromised is if you root your phone and share your data yourself.  Even if it were possible (and you can be assured it's not possible without internet access permission) Neural Direct will not collect/analyze/sell/redistribute your data.  It's your data and yours alone.  Period.

If your phone is Android 6.0 or later, then if you've enabled automatic backups for your phone Google will backup your app data to your Google Drive account.  The Last Time participates in this program, but none of your data passes through any server of ours.  Google handles it.  You should refer to Google's privacy policy if you have concerns about them accessing your data in your Google Drive account.