The decision to compact the activities of Sligo New Music Festival into a single day was a sensible and rewarding one. The music of Sicilian composer Salvatore Sciarrino was the subject of this year's festival, and the range of adjustments Sciarrino demands from his listeners were facilitated by the day's three-concert format.

Sciarrino, now in his mid-50s, is a self-taught composer who, quite early in his career, developed his own readily identifiable sound world.

"The music that I write extends to the limits of perceptibility, right up close to the point of silence, seeking to look into the space of the mind," he once explained. The earliest of his works heard in Sligo, the Due studi for solo cello from 1974, set the tone by concentrating on ethereal cello harmonics and the whistling sounds that can be produced when the player keeps the bow close to the bridge.

This was followed by the first of three works for solo flute, Lettera degli antipodi portata dal vento, written in 2000. The programme also included a second work from that year, Immagine fenicia, and the earlier Come vengono prodotti gli incantesimi? of 1985. The tone of the flute is the material from which Sciarrino has excavated his most characteristic sonic gestures. It's as if he has examined the instrument's familiar allure, its round, appealing tone, and asked himself what would be left if you subtracted its core.

Elements he chooses to work with are those faint, eerie trails that live within the wispier notes on the flute, the hollow sounds of rushing air, and soft high notes that sound as from afar, almost as from another time.

Sometimes there are moments to shock - overblowing in violent blasts, or low, animal throbs and strange implorations.

Sciarrino's approach to the piano sometimes takes off in an entirely different direction. "For me," he has said, "this instrument is a field through which figures pass and transform, where sound becomes fused and reshaped by velocity or by percussive energy."

His Third Sonata of 1987 has a driven quality and a wild angularity, creating an effect not unlike an intentionally naïve and over-the-top mimicry of the extremes of 1950s Serialism - there are even cluster glissandos, for which the player needs the protection and reduced friction of woollen mittens.

There's something extreme and obsessive about Sciarrino's work as it inhabits a "threshold region", which he has described as being "like dreams, where something both exists and does not yet exist, and exists as something else as well".

This was at its clearest in the long pieces which were reserved for the evening concerts. Vanitas (1981) is a "still life" (natura morta in Italian) in one act for voice, cello and piano, a dream-distorted song, recursive, haunting, loaded with heavy but indistinct meaning, and so oddly proportioned that the final five-minute descent on a single sliding cello note maintains itself with gripping inevitability.

Sciarrino describes the closing work, La perfezione di uno spirito sottile (1985), for voice and flute as "a musical ritual, to be performed in the open, beside cliffs, crags, strange rocks, or on boundless plateaux - but also inside, against a white wall".

The Model Arts and Niland Gallery has such a white wall to serve as background to this Chernobyl-inspired threnody, with voice and instrument sharing a mood of keening numbness, the singer sometimes locked in repetition as if coping with the incomprehensible.

The day's performances, by mezzo-soprano Sonia Turchetti and members of Italian ensemble Alter Ego, were a model of what the presentation of such challenging music needs to achieve - a sense of absolute identity with the composer's wishes.