Entering into the black box space, we are met by three downtrodden figures. They sit crumpled, staring into space. There is little real set, bar a rarely-used hat stand. But the ceiling is littered like a charity shop: bikes, birdcages – a trinket host.

The Man Who is based on Oliver Sacks’s neurological study The Man Who Mistook His Wife for a Hat. In the original, Sacks recounts encounters with a survey of patients suffering from a variety of neurological disorders. It was adapted for the stage by Peter Brook and Marie-Helen Estienne in 1994, touring nationally including a stint at the National Theatre. Sleight of Hand brings its version to Tristan Bates Theatre.

We begin with a shunt, straight into an interview with an unsettled patient (Holly Piper). Her slips into chaos are sharp. The ground laid out before us is unsafe, certainly, but this is a production that should be credited for giving us a portrait of a world that is as touching as it is uncomfortable.

The variety of characters is vast: Danny Solomon’s French gentleman with severe lapses in memory; a scene between two of Solomon and Jake W Francis’s other characters who recognise objects and each other only as colours or shapes. In the play’s most moving scene, Francis plays a man who can maintain a fluid conversation in utter gibberish, can read and respond successfully to physical signals, but when asked to pick up the comb from a box of objects frets himself into a frenzy.

The scenes taken individually are the production’s strength. Quality is maintained almost unilaterally throughout. Characters’ physicalities are consistently nuanced, many containing precise touches of Ellie Chadwick’s direction that create genius from what must be a script open to infinite interpretation. At one point I became transfixed by an innocuous conversation: the doctor (Francis) contorts his own hand into the sightline of his patient (Solomon). The patient mistakes it for his own numb copy hanging limply at his side. It is a scene that hangs deftly between humour and heartbreak as Solomon’s certainty crumbles into confusion. Time and time again we see vulnerable individuals step out of their own time-capsule-like minds into frightening unfamiliarity, a journey they must make hundreds of times a day.

While the concept works well from scene to scene, it is, however, problematic overall. The interviews give us a mesmerising cross-section, yes, but they aren’t arranged to give us any narrative arc. Bar the comb-fetching scene, they might have come in any order and produced an equal effect.

Seen as a whole, holes in the acting and direction – admittedly a heavy task considering the number of characters – are exposed. The actors do a fine job to individually capture each physical aspect, but seeing the body of these performances in quick succession, the idiosyncrasies of the actors themselves are highlighted: the stiffness in Francis’s fingers, Solomon’s wide-eyed stare, and the way Piper too often puts her strongest stress on the second syllable of a line. All these tics needed to be ironed out in rehearsals.

In a few ways, the production is still fairly rough around the edges. Though soundtracking and original composition alike are to be highly commended, cues often come crashing in or are snatched away in distracting fashion. The choreographed movement of the actors during transitions often lack the precision of the scenes themselves.

All that said, there is a huge amount of gratification to be gained from Sleight of Hand’s production. The characters from the script are a gift, but I’m sure it has taken a craftsman’s hand to take them from the page to the stage and give them life. To be enjoyed for the small moments of ingenuity, the gentle inflections of characterisation, as well as the warmth and chemistry between the cast, this is a hugely worthwhile show.

The Man Who is playing at Tristan Bates Theatre until 28 March. For more information and tickets, see the Tristan Bates Theatre website.