Martha Loader’s new play tackles a devastating topic with sensitivity and at times brutal honesty. Splinter is the story of Maggie (Henri Merriam) and Jac (Sarah Livingstone and Caroline Rippin), who are the very definition of “opposites attract” – while Maggie is a free-spirited activist with a fear of commitment, Jac is responsible, organised and longing to settle down. Despite the odds, their relationship works, but when Maggie is diagnosed with early onset dementia, their bond is tested to the limit.

Loader establishes a clear divide from the start between “before” and “after”, with alternating scenes that skip backwards and forwards in time. On the one hand, we see Maggie and Jak meet, fall in love and build a life together; on the other, we see that life begin to fall apart, a little at a time. The dementia diagnosis comes quite late in the play, which actually makes the scenes that come before it even more difficult to watch, because both women know something is wrong but can’t identify the cause. There’s a particularly clever detail in the way Jak occasionally seems to say the wrong word; just like Maggie, at first we brush it off as a slip of the tongue or assume we misheard, and it’s only as these become more common that we too start to realise something else might be going on.

There’s heartbreaking significance, too, in the decision to have Jak played by two different actors, while Maggie is played throughout by the same person. That significance doesn’t become completely clear until later on in the play, and the moment of realisation arrives in a dramatic scene that marks a clear turning point for both characters. Sarah Livingstone and Caroline Rippin mirror each other well in their mannerisms and interactions with Maggie, but at the same time they’re also clearly unique versions of Jak, demonstrating how a diagnosis like this isn’t only life-changing for the person who receives it, but also has a profound impact on those around them. Henri Merriam is on stage throughout and is mesmerising as Maggie in both eras; “before” Maggie is full of an infectious energy, passion and mischief, which we see drain away over the course of the play, leaving “after” Maggie lost and bewildered

Becca Gibbs has created a beautifully versatile set, featuring a window, bookcase and door, which are moved about after each scene to set up new locations. By keeping Maggie on stage during these scene changes, director Amy Wyllie adds an element of disorientation to the constant movement – but always brings us back to the central motif of Jak, endlessly sticking post-it notes to the bookcase in a futile attempt to help Maggie hold on to details of their life together.

Dementia is a cruel disease, and Splinter demonstrates very well the damage it can cause, by taking us on a journey with this perfectly imperfect couple. Apart from one incident late on in the play that comes out of nowhere and feels like it deserves more time (largely because it has the potential to change how we feel about one of the characters), this is a well crafted and powerfully performed story that really draws us in, to ensure that we feel the full impact of the events that follow. The nature of the condition means it’s not a spoiler to say this story was never going to have a happy ending, but the conclusion we get is sensitively handled and, in a way, feels as optimistic as it’s possible for it to be.

Splinter is at the Jack Studio Theatre until 2nd December.