When the fits arise from a post-central source of irritation, they are usually preceded by well-marked sensory auræ--tinglings, burning and painful sensations--again according to the region affected.
When preceded by sensations of taste and smell, the lesion is probably situated over the anterior part of the temporo-sphenoidal lobe.
When by visual impressions--flashes of light, &c.--the lesion is probably situated over the occipital lobe of the brain.
=Pathology.= The pathological conditions responsible for the development of fits are various, resolving themselves, when fully investigated, into two main groups: those associated with meningeal changes only, and those accompanied by definite cortical scarring and tract degeneration.
In the event of osseous deficiency the scalp is usually more or less adherent to underlying structures, and the gap in the skull filled with dense fibrous tissue, which is itself adherent to the membranes of the brain and perhaps to the brain itself.
In the absence of osseous deficiency, the cerebral irritation is usually dependent on depressed fragments of bone, on subdural hæmatomata and cysts, and on meningeal thickening.
In the event of cerebral degenerative changes it may be presumed, whether there is a deficiency in the bone or not, that considerable matting of meninges and cortex is existent with pyramidal degeneration.
In the absence of evident signs of external injury, cases of focal epilepsy in the young require careful investigation, inquiry being made as to difficult labour, for, as Harvey Cushing points out, ‘When we consider the widespread lesions associated with those cases that later on are recognizable as Little’s disease, and that presumably an enormous number of children receive at birth some trifling injury which, from lack of symptoms, is overlooked, may it not be that many cases of so-called idiopathic epilepsy dating from childhood can be safely attributed to the effects of early traumatism?’
In all these, and in other doubtful cases, before undertaking surgical procedures, the surgeon should obtain the services of a skilled neurologist.
=The clinical course of the case.= If a typical case of Jacksonian epilepsy can be observed from beginning to end, many curious and interesting features will be observed. The fits, at first typically Jacksonian, gradually lose their typical character, becoming more frequent and less focal in nature, the patient losing consciousness during the fit, and the fits succeeded by weakness or paralysis of the parts primarily involved. The general mental state of the patient suffers proportionately--he becomes morose, despondent, irritable, homicidal, or suicidal in tendency. How far these retrograde symptoms are dependent on degenerative processes in the brain, and how much they result from the moral effect of the frequent epileptiform seizures, are questions that can only be determined by observing the effect of treatment, surgical or otherwise. Some cases respond readily to treatment, others are too far advanced to experience any material benefit, some end their days in the lunatic asylum.