For some, this may be a very difficult film, dismissing the split-screen and the main characters merely termed him and her (Lui et Elle), as the viewer is confronted with the cruelty of dementia and its effects on others.

I know about the horror of this illness; the gradual disintegration of a person’s mental capacity, while the other half of a very long and loving relationship, can do little more than hold their hand, offering and receiving comfort.

It’s not long into Vortex before it becomes obvious that Elle (Françoise Lebrun) is in almost no condition to look after herself, relying on her husband Lui (Dario Argent) for support although she has little or no awareness of that due to her condition.

For his part Lui tries to continue with his routine and life; writing his book and his academic meetings with friends. Trying to become involved but recovering from his own difficulties is their ex-junkie son Stéphane (Alex Lutz) with his son. And what basically follows are a series of vignettes of Elle’s collapse and Lui’s frustration and anger at her actions and his inability to help.

A film like this dealing with this subject cannot end happily, that’s a given, not a spoiler. Anyone who has been involved will know that with either one or other of the partnership collapsing. What it can illustrate is the love that at time appears to be one-sided, though short periods of lucidity is mutual and deep. In that there’s a forever attachment to them and their surroundings.

The pressure is to sell up and go to a residence where they can both be looked after. But Lui is completely against this arguing that there’s a lifetime of work, collection and memories there that collected go well beyond mere objects, having a long time ago become mental support, arguably crutches.

Gaspar Noé has elicited brilliant performances for all involved with Argento sublime as a husband who could be looked on as totally unsympathetic at times. However he’s skilful enough to show that his behaviour is a times understandable, at others, could be accused of neglect?

Lebrun matches him word for word and look for look, her confusion heart-breaking as she is tracked around the flat, picking things up, possibly at random. She actually manages to convey an essence of logic here for example when she tidies up Lui’s complete mess of an office destroying his work.

The subject matter, and the events not that far in the past, makes it difficult to appreciate in any other way than personal. However it is an extraordinary film that I think will resonate with many people beyond those that have been personally affected.