With a rapidly ageing population dementia has become more and more prevalent in our society; over 350,000 Australians are known to live with the debilitating condition. Karen Sibbing’s ODE offers a window into what that is like: drawing from the experience of watching her own grandmother succumb to it, she imagines a world as seen through the eyes of a sufferer. The result is devastating, but tender, bookended with an unmistakable impression of hope.

Lighting, under the skilful direction of co-creator Samara Hersch, turns into a powerful tool. In one — no, two — occasions the theatre is plunged for longer than anybody would be comfortable with into complete darkness, in which feelings of disorientation, of visceral susceptibility, desperation to want to find whatever trace of glow there is, seem to close in on us, like walls, like possibly the mental incapacity.

Near the opening of the 55-minute, one-woman show, the character relates a childhood incident where she witnesses the way her young brother’s wilful act of wandering off in a play-fair and getting lost yielded not punishment but a lollipop from their father. Despite carrying a brooding sense of premonition and whiff of unfairness — spoken in the present tense, perhaps to neutralise the influence of time — the fascinating anecdote conveys the idea of reward from tragedy that is premised on blessing in perspective.

For the rest, though, it is mostly through texture that Sibbing works. Small, intricate, observational details give us a glimpse of surviving with Alzheimer’s: hearing sounds in the head, having an imaginary friend in a toy, wolfing down handfuls of cakes on impulse, enduring bouts of frustration and anguish.

Whilst it is her grandmother whom she is depicting, Sibbing, we realise, has braided into the play her own anxieties of decline and ultimately of herself falling victim to this incurable illness.

The antics are theatrical but in all likelihood very real. A lot appears to happen and at the same time not much at all, like the ever-growing balloon that instead of popping sucks away, loses air, shrivels and limps, because that is probably life when you lose yourself.

Sibbing’s performance is outstanding: brave and heart-clutching and luminous, she embodies without reproach the volatile, vigorous, vulnerable part. The helplessness, as she stares into the distance, urine pouring down from between her legs, tears welling, is enough to make a stone weep.

Is it disconcerting? Yes, most definitely, for it forces us to confront manifestations of an unseen tormentor, so often untold.

Yet, there is a curious air of eerie magic permeating through the piece — amplified when the giant revolving image of a musical-box dancer projected on an opposite wall is the only illumination in the room — a magic none more precious than the gift eventually granted to Oma (grandmother), the gift of imagination, to which this timeless work is ode.