His group did brain scans of students who listened to lists of related words, then were asked later whether or not certain words were on the lists. These students showed increased brain activity in the hippocampal area and frontal lobes. That's too simplistic. We must be very careful to separate laboratory experiments using lists of words from memories of real events. In addition to sounds, such memories involve fears, expectations, desires, and other emotions.
Additional obstacles exist.
But a greater limitation is that the machine reveals no absolute differences in brain activity, only comparisons. It shows what the brains of 12 students look like when they have true or false memories. It will not tell you whether the experiences of someone who claims she has been abducted by aliens are real or imagined. Nor will it determine the veracity of recovered memories of rape and murder without additional collaboration. The imagination can be as powerful as true memory.