Puppetry and dementia aren’t the most obvious partners. Normally associated with slapstick silliness, it’s hard to imagine how puppets would provide a poignant vehicle for expressing painful stories. But the delight of Dark Matter is that it harnesses everything puppetry has to offer – from the doll’s apparent weightlessness as hands move it through the air, to the delicacy of its movements – to reflect the fragile experience of living with dementia.

Dark Matter is beautifully conceived. Our protagonist, Alfie, is introduced to us as an old man. His puppet head is heavy, his limbs are weak and he moves with difficulty. His voice (acted perfectly by Daniel Moseley) is cracked with age, trembling with confusion, and utterly believable as he oscillates between fear, uncertainty, wicked humour and childish silliness.

It’s refreshing that we get to see Alfie’s behaviour shift so erratically. There’s no attempt to smoothe over all the real, disconcerting and uncomfortable behaviour which makes dementia so taboo. We share in his carer Anna’s (Sofia Calmicova) exasperation as he forgets names, refuses medication and lashes out in fear. He manages to be both a likeable man and a difficult patient, and it’s the accuracy and complexity of his behaviour which makes Dark Matter such a socially responsible piece of theatre.

We watch as Alfie confuses the past for the present, his care home for a five star hotel and a much-needed bath for a physics conference. As Alfie’s mind moves into the past, it’s poignant that his puppet form remains identical. The same, age-bent old Alfie leaps around his childhood home, bleating plaintively to “Mama” that he “won’t go to church”, and his wrinkled hands clutch a book that we recognise from his present day care home setting. It’s an elegant representation of Alfie’s past and present selves melting together. As the skillful puppeteers Moseley, Calmicova, Almudena Adalia and Aurora Adams move him, Alfie is lighter than any ballet dancer. These dances, in which Alfie wanders lost through his own memory are some of Dark Matter’s finest scenes.

Dark Matter impressively knits together a world of meaning in which the details of Alfie’s life – particularly his past career as an astrophysicist – resonate with his interior, emotional world. We see the childhood Alfie gain great freedom from proudly declaring “I am an atheist”, but that same atheism leaves him terrifyingly unmoored as an adult searching for meaning in the universe. With a pleasing sense of closure, Vertebra theatre company recycle props as a reminder of how trapped Alfie is by his memories. The red scarf his wife wears becomes the prow of a ship as he sails through a twinkling starscape, and the book which prompted his scientific revelations as a youth becomes the book of his own authorship, the only symbol of his life before dementia.

If the structure of Dark Matter is disjointed, that’s as it should be. The narrative sequences flit through a dozen tones, just as the hero himself swaps ages and identities. He shifts from spiky humour into sweet immaturity in a jiffy, and it’s the unexpected intrusion of comic lines, like “did you know astronomy comes from gastronomy?” or “no, you smell!” that renders him so likeable.

Watching any puppet show requires a little conscious effort from the audience. Like trying to forget about the subtitles as you watch a foreign film, one needs to look past the gathered hands and bodies which move the puppets bodies. The lighting is too bright and the puppeteers’ clothing too varied for anyone to actually fade into the background, but Vertebra do their supportive work subtly enough to go unnoticed, allowing this star of a show to shine.

Dark Matter is playing the Etcetera Theatre until 11 August. For more information and tickets, see Camden Fringe website. Photo by The Camden Fringe.