Away From Her (cert 12A, 105mins) at Pictureville from tomorrow Four stars

Adapted from a short story by Canadian writer Alice Munro, Away From Her is a wintry tale about a couple's 50-year marriage slowly dissolving in the fog of Alzheimer's disease.

Julie Christie gives one of the finest performances of her career as Fiona Andersson, the sixtysomething wife of a retired academic whose illness parts her first from a settled home and then from her devoted husband Grant (Gordon Pinsent).

Placed into long-term care, Fiona gradually loses all memory of the man with whom she has spent all her adult life and attaches herself instead to fellow patient Aubrey (Michael Murphy), who is wheelchair-bound and unable to speak.

A traumatised Grant has to decide whether to cling on to Fiona or to follow her instruction to "Go now" and try to find happiness with Aubrey's wife Marian (Olympia Dukakis).

Such painful dilemmas of the heart are deftly dealt with in Sarah Polley's debut feature film as writer and director. Rather than dwelling on the story's morbid aspects or lapsing into sentimentality, Away From Her becomes a celebration of life and love, directed with subtlety and insight.

The sequence where Grant takes Fiona on a "field trip" to her former Ontario home, in particular, is almost unbearably poignant while the scene where salt-of-the-earth nurse Kristy (Kristen Thomson) challenges the former university lecturer over his past marital infidelities with female students shows how much Grant's actions are motivated by guilt.

With Christie living up to her character's description as "ethereal, light and sly", Pinsent is an excellent counterweight, sad and remorseful. Rounding off a first-rate cast is Dukakis, all feisty and sage on the outside and vulnerable underneath.

Away From Her shows at the National Media Museum's Pictureville cinema until Thursday. Contact 0870 7010200 for details.