Can a trial court preclude a defendant’s voice exemplar if he chooses not to testify?

Interesting case out of Missouri. At trial, the State played a video of the defendant after he was arrested for OWI and pointed to his speech pattern as evidence of intoxication. In response, the defendant sought to offer a voice exemplar to show that this was his normal speech pattern. However, he also did not want to testify. The court of appeals held that the trial court could not exclude the exemplar on the grounds that the defendant refused to take the stand and submit to cross-examination, citing a long list of cases which you will find here. Note, however, that the court of appeals excluded the voice exemplar on other grounds.