After this season’s “Messiah,” I found myself humming or singing sections of Handel’s oratorio for several weeks. If it wasn’t “He Shall Purify,” it was “For Unto Us a Child is Born” running through my head. According to Oliver Sacks, this is normal. Most people can remember parts of music they really like and repeat them accurately, if not in good voice.

However, Sacks’ new book, “Musicophilia,” subtitled “Tales of the Brain and Music,” takes such innate musical abilities several steps further. In it he relates stories of numerous patients who suffer some mental illness or aberration that manifests itself in music.

As in all of his other books, Sacks is trying to make sense of how the brain works from these professionally notated anecdotes. What patterns are there Are there common injuries, areas of the brain affected, or similar symptoms The brain may be the last “undiscovered country,” and music may be the key.

Much of “Musicophilia” are case studies, starting with the story of surgeon Tony Cicoria who developed a passion for listening and playing music after he was struck by lightning. Apparently undamaged otherwise, Cicoria became a competent pianist, teaching himself how to play at 42. For Cicoria, the onset of music ability was an unquestioned blessing.

For Clive Wearing, music is the only time that he is able to sustain time. After a severe brain inflammation, Wearing lost all of his memory. He lives only in the present. If he looks away from a candy bar in his hand and then looks back, it is a new candy bar. Clive meets a visitor anew each time he turns around and has no memory that the guest never left the room.

Wearing had been a renowned musicologist and a competent pianist before, and it was only at a piano that time has any duration. Playing Bach he can sustain the piece from one measure to another, but as Sacks calls it, this is only automatism. Wearing can only play if directed to the piano, music put up for him to play, and practice regulated this way by someone else. Otherwise Wearing is stuck in “now;” there is no yesterday or even a moment ago.

Other patients have less debilitating symptoms. Some apply colors to music. Major and minor keys are color-coded. To composer Michael Torke G-minor is a subdued yellow ochre, G-major bright yellow, D-major blue, and so on.

When another professional musician in Europe hears a specific interval, “she automatically experiences a taste on her tongue that is consistently linked to that musical interval.” A minor second is sour; a minor third is sweet; a major sixth is low-fat cream; and an octave has no taste at all.

Both color and taste mixed with music are examples of synesthesia, where the brain mixes senses for the individual. Some people see numbers with different colors. These musicians do that and associate other senses with music besides hearing.

Oliver Sacks has been fascinated with such quirks in the human psyche for a long time. For example, most of the patients with synesthesia also have absolute pitch, normally a rare occurrence. Sacks compares this with absolute pitch in those who are blind from birth. There is evidence that babies have absolute pitch and are soon learned out of it by visual cues. If one is blind from birth, absolute pitch may stay.

There is even some conjecture that learning a language requires the negation of absolute pitch, except, perhaps, in tonal languages such as Vietnamese or Mandarin Chinese. Ideas like these constantly confront the reader of Sacks’ books, but there is one crucial difference. Sacks always supports his conjectures with documented scientific studies, and his bibliography in the back is extensive.

We readers, however, are not usually interested in such exactitude. We want more stories of the frailties of the human brain, such as Tourette’s syndrome, an impulsive behavior shown by tics, awkward gestures, and flailing of the limbs.

Sacks relates that in the Tourette’s community, it is known that drum circles and drumming have therapeutic powers. He attended a drum circle in New York City, where before the drumming started everyone in the room was ticcing in his own time. Once the drumming began, all the ticcing disappeared within seconds.

Music also provides a link for those afflicted with Williams syndrome. Such children and adults rarely have an IQ above 60 but are loquacious, highly sociable, and musical. They cannot count cookies on a tray but can play preludes by Bach. They cannot live independently, but they tell stories easily with erudite vocabularies and have learned operatic arias in 30 languages.

Sacks, however, does not posit music as a cure for such syndromes and maladies. When Clive Wearing stops playing the piano, he goes back to his isolation in time. When the drumming stops, the tics begin again. Sacks recognizes that music gives us simple pleasure and a haven only for a while.