To watch this film you have to remember it's set in the '50's and the idea at the start of the picture was revolutionary. Using an ECG a couple of doctors are able to diagnose a person's mental health. On one occasion they bring in a deranged killer to get a reading. Then later, they have an accident victim who they scan for brain damage. upon checking his scan they see he has some alarming similarities with the killer. Before they can question him he leaves the hospital. The story then starts to take a weaving path to its conclusion.
It's this path that makes the movie watchable as you wonder what's happening and what will happen next. It's the pace of the movie and the acting which hinder the movie somewhat. The bad guy, Frank Smith (Maxwell Reed) just doesn't have the aura of a psychopathic madman - he sure does know how to shout though. It would have been a lot better had he run a gamut of emotions to show his mental breakdown.
I also liked the fact that the female Doctor Philippa Roberts (Elizabeth Allan) is a strong woman that knows and says her mind. Unfortunately, she loses this confidence when she is kidnapped by Smith. Again, this would have been great had she retained this and not regressed into screaming woman. But this was made in the '50's so has their ideals.
I reckon this story would still make a good movie today, even a great one if the issues are addressed as I can still see the issues used in the story being relevant today.
If you like your old black and white mysteries, then you may like this. But be aware, this is not the best of it's kind. Definitely, one to watch when sick in bed... though remember to keep the remote handy for when things get shouty.