Table 3. Localization-Related (Focal, Local, Partial) Epilepsies and Syndromes

1. 2 Symptomatic

• Chronic progressive epilepsia partialis continua of childhood (Kojewnikow's syndrome)
  
  Syndromes characterized by seizures with specific modes of precipitation
  Temporal lobe
  
  Frontal lobe
  • Supplementary motor seizures
    Cingulate
    Anterior frontopolar region
    Orbitofrontal
    Dorsolateral
    Opercular
    Motor cortex
  
  Parietal lobe
  
  Occipital lobe
  

They may be anatomically categorized, for example, into seizures arising from the rolandic area, the supplementary motor area (SMA). from polar areas (Brodmann areas 10, 11, 12, and 47), the dorsolateral area, the opercular area, the orbital region, and the cingulate gyrus. Rolandic seizures are typical jacksonian simple partial attacks, while SMA-derived attacks often lead to adversion with posturing and autonomic changes. Characteristic features of complex partial seizures arising from frontal areas include frequent clustering of brief seizures, with sudden onset and cessation. Often, the accompanying motor behavior may be bizarre; and, since the surface electroencephalogram (EEG) may be normal, these attacks may readily be diagnosed as hysterical pseudoseizures.

SCHIZOPHRENIA

That neurologic abnormalities underlie the clinical condition schizophrenia is now secure knowledge (see Hyde and Weinberger in this issue of Seminars). However, the precise pathologic lesions and the localization of the abnormalities continue to arouse interest and controversy. Much recent work has highlighted abnormalities of frontal lobe function in this condition. Several authors have drawn attention to the likeness of some schizophrenic symptoms to frontal lobe disorder, in particular that involving dorsolateral prefrontal cortex. Symptoms included are those of the affective changes, impaired motivation, poor insight. and other "defect symptoms." Evidence for frontal lobe dysfunction in schizophrenic patients has been noted in neuropathologic studies, (23) in EEG studies, (24) in radiologic studies using CT measures, (25) with MRI, (26) and in cerebral blood flow (CBF) studies. (27) The last have been replicated by findings of hypofrontality in several studies using positron emission tomography (PET). (28) These findings emphasize the importance of neurologic and neuropsychologic investigation of patients with schizophrenia, using methods that may uncover underlying frontal lobe disturbances, and the important role that frontal lobe dysfunction may play in the development of schizophrenic symptoms. (23)

DEMENTIA

The dementias are assuming increasing importance in psychiatric practice, and progress has been made with regard to classifying them and to discovering their underlying neuropathologic and neurochemical basis. While many forms of dementia involve frontal lobe changes, it is now clear that several types of dementia more selectively affect frontal lobe function, particularly early in the disease. The paradigm of frontal lobe dementia is that described by Pick in 1892, which was associated with circumscribed atrophy of both the frontal and temporal lobes. This form of dementia is much less common than Alzheimer's disease. It is more frequent in females. It may be inherited through a single autosomal dominant gene, although most cases are sporadic.

There are distinguishing features that reflect the underlying pathologic changes of Pick's disease and separate it from Alzheimer's disease. In particular, abnormalities of behavior, emotional changes, and aphasia are frequent presenting features. Some authors have noted elements of the Kluver-Bucy syndrome at one stage or another in the disease. (29) Interpersonal relationships deteriorate, insight is lost early, and the jocularity of frontal lobe damage may even suggest a manic picture. The aphasia is reflected in word-finding difficulties, empty, flat, nonfluent speech, and aphasia. With progression, the cognitive changes become apparent: these include memory disturbance but also impairment on frontal lobe tasks (see later). Ultimately, extrapyramidal signs, incontinence, and widespread cognitive decline are seen.

The EEG tends to remain normal in this disease, although CT or MRI will provide confirmatory evidence of lobar atrophy. The PET picture confirms diminished metabolism in frontal and temporal areas. Pathologically, the brunt of the changes is borne by these areas of the brain and mainly consists of neuron loss with gliosis. The characteristic change is the "balloon cell" which contains disordered neurofilaments and neurotubules, and Pick bodies, which are silver-staining and are also composed of neurofilaments and tubules.