@ Traverse Theatre, Edinburgh, until Sat 24 Oct 2015

Those who use A Play, A Pie and A Pint as light relief from the working day are coming to the wrong place this week. Linda Duncan McLaughlin’s Descent is a direct and arresting portrayal of a man in the throws of early onset dementia and it’s as discomfiting as it sounds.

Architect Rob (Barrie Hunter) is a likeable chap in his fifties, fulfilled in his career, still playfully in love with his wife, and contendedly rolling through middle-age with only the odd memory lapse and grumpy moment to mark it. As it transpires, these senior moments have a more serious provenance, and as the Rob of old painfully begins to disappear, daughter Nicola (cold, pragmatic) and wife Cathy (loving, exhausted) negotiate how to accompany him on this tortuous one-way journey.

Scenes seem to suggest an intimate, personal acquaintance with the dynamics of dementia on behalf of the writer, and even if that’s not the case, the list of credits shows how thoroughly it’s been researched. The trajectory of the “descent” has been very well measured. We see just enough of Rob in full health to get a grasp of the man in the round, before we see the illness stealing and manipulating his mind. His dementia has its own idiosyncrasies, sufficiently unique to be believable, while retaining a universality. Hunter convinces throughout, displaying frustration, disconnection, anger, bewilderment, innocence – the full gamut.

The play errs to the telling rather than the showing in places though. It’s at its most powerful in heartbreaking moments shared between Rob and his wife, played with compassion by Wendy Seager – particularly the scene where violence turns to tenderness as an insensible Rob regains composure and doesn’t realise he’s been beating his wife. Set against this, the inner monologues delivered to the audience offer little extra. Actions have spoken louder than words.

After a climactic scene, sinisterly lit and soundtracked, in which Rob’s forgetfulness reaches a new, dangerous low, the ultimate finale feels a touch slight. Nonetheless, the three strong cast (Fiona MacNeil playing daughter Nicola) and director Allie Butler have done full justice to this balanced, dignified and deeply sad portrayal of a frightening human experience we might all have to face.

Part of Luminate, Scotland’s creative ageing festival