In contrast to such generalized seizures, which arise from an inborn, genetic sensitivity of the brain, partial seizures arise from a particular area of damage or sensitivity in one part of the brain, an epileptic focus, which may be congenital or the result of an injury. The symptoms of partial seizures depend on the location of the focus: they may be motor (twitching of certain muscles), autonomic (nausea, a rising feeling in the stomach, etc.), sensory (abnormalities or hallucinations of sight, sound, smell, or other sensations), or psychic (sudden feelings of joy or fear without apparent cause, déjà vu or jamais vu, or sudden, often unusual, trains of thought). Partial seizure activity may be confined to the epileptic focus, or it may spread to other areas of the brain, and occasionally it leads to a generalized convulsion.
Partial or focal seizures were only recognized in the second half of the nineteenth century—a time when focal deficits of all kinds (for instance, aphasia, the loss of linguistic ability, or agnosia, the loss of ability to identify objects) were being described and attributed to damage in specific areas of the brain. This correlation of cerebral pathology with specific deficits, or “negative” symptoms, led to the understanding that there are many different centers in the brain crucial to certain functions.
But Hughlings Jackson (sometimes called the father of English neurology) paid equal attention to the “positive” symptoms of neurological disease—symptoms of overactivity, such as seizures, hallucinations, and deliria. He was a minute and patient observer, and he was the first to recognize “reminiscence” and “dreamy states” in complex seizures. We still speak of focal motor seizures which start in the hands and “march” up the arm as Jacksonian epilepsy.
Jackson was also an extraordinary theorist, who proposed that higher and higher levels had evolved in the human nervous system—and that these were hierarchically organized, with higher centers constraining lower ones. Thus, he thought, damage in the higher centers might cause “release” activity in the lower ones. For Jackson, epilepsy was a window into the organization and workings of the nervous system (as migraine was for me). “He who is faithfully analyzing many different cases of epilepsy,” Jackson wrote, “is doing far more than studying epilepsy.”
Jackson’s younger partner in the enterprise of describing and classifying seizures was William Gowers, and where Jackson’s writing was complex, convoluted, and full of reservations,
Gowers’s was simple, transparent, and lucid. (Jackson never wrote a book, but Gowers wrote many, including his 1881
Gowers was especially drawn to the visual symptoms of epilepsy (he had previously written a book on ophthalmology), and he enjoyed describing simple visual seizures, as with one patient, for whom, he wrote:
The warning was always a blue star, which appeared to be opposite the left eye, and to come nearer until consciousness was lost. Another patient always saw an object, not described as light, before the left eye, whirling round and round. It seemed to come nearer and nearer, describing larger circles as it approached, until consciousness was lost.
Jen W., an articulate young woman, came to see me several years ago. She told me that when she was four, she saw “a ball of colored lights on the right side, spinning, very defined.” The ball of colored lights spun for a few seconds and was succeeded by a greyish cloud to the right, obscuring her vision to that side for two or three minutes.
She had further visions of the spinning ball, always in the same place, four or five times a year, but she assumed that this was normal, something everyone saw. When she was six or seven, the attacks took on a new aspect: the colored ball was followed by a headache on one side of her head, often accompanied by an intolerance of light and sound. She was taken to a neurologist, but an EEG and CAT scan revealed nothing, and Jen was diagnosed with migraine.
When she was thirteen or so, the attacks became longer, more frequent, and more complicated. Sometimes these frightening attacks led to complete blindness for several minutes, along with an inability to understand what people were saying. When she tried to talk, she could only utter gibberish. At this point, she was diagnosed with “complicated migraine.”
