Tower Clinical Trials (United States)

(D) “So, you got all that information off your Apple Watch?” (P) “Yes, Sir. And I’ve been recording my sleep activity for several months now.” (D) “Do you think there is a possibility we can track your blackouts by looking at your sleep data from the night before?” (P) “What do you mean?” (D) “That with a poor night’s sleep there is a high probability that you will have a blackout the next day.” (P) “I never thought about my blackouts having anything to do with my sleep habits.” (D) “I’m guessing that there is a one-to-one correlation between a lack of good sleep, and blackouts the next day. Should we start tracking this?” (P) “Okay, I mean my watch gives me a lot of data so why not?’ (D) “If we can prove this, then I think we have stumbled on something very important and very useful in your treatment.” With this doctor-patient exchange I came across the idea/ conception/insight that it was possible to predict when my patient was going to experience a blackout, some of which were very dangerous for her. At first this appeared to be a wild and crazy idea.

This article illustrates the use of latent transition analysis (LTA), a methodology for testing stage-sequential models of individual growth. LTA is an outgrowth of latent class theory and is a particular type of latent Markov model emphasizing the use of multiple manifest indicators. LTA is used to compare the fit of two models of early adolescent substance use onset and to assess the effects of a school-based substance use prevention program on Ss measured in 7th grade and again in 8th grade. Several interesting findings emerged. First, a model of substance use onset including both alcohol and tobacco use as possible starting points fit better than a model that included alcohol use as the only starting point. Second, Ss who had tried tobacco but not alcohol in in 7th grade seemed to be on an accelerated onset trajectory. Third, the normative education prevention program was generally successful, except for the students who had tried only tobacco in 7th grade.