Prior Testimony

1. The testimony or depositions of a witness deceased or unable
   to testify
2. The testimony was given in a former case or proceeding, judicial
   or administrative
3. Involving the same parties
4. Relating to the subject matter
5. The adverse party having had an opportunity to cross-examine him.

The prior testimony must have been made by a witness deceased or
unable to testify, in a former case/proceeding (judicial or
administrative) involving the same parties and subject matter.

Unable To Testify
An inability proceeding from a grave cause almost amounting to
death as when the witness is old and has lost the power of
speech.(Tan v. CA (1967)

The prior testimony may be given in evidence against the adverse
party who had the opportunity to cross-examine the witness.