Parietal and Occipital Lobe Epilepsy: A Review

Abstract

There has been considerable recent interest in frontal lobe epileptic syndromes, and less attention paid to occipital and parietal epilepsies. The occipital and parietal lobes have arbitrary anatomical borders. The prinicpal seizure symptomatology includes somatosensory (paresthetic, painful, thermal, sexual, apraxia, disturbances of body image); visual (amaurotic, elementary and complex hallucinations, illusions) and other phenomena (anosognosia, apraxia, acalculia, alexia, aphemia, confusional states, gustatory, vertiginous, adversive, oculoclonic and eyelid flutter). The seizure symptoms are of varying localizing and lateralizing value and seizure discharges may spread rapidly and perceived symptoms may reflect secondary spread rather than the primary site of seizure onset. Recognized parietal and occipital epilepsy syndromes include benign epilepsy of childhood with centrotemporal spikes, benign epilepsy of childhood with parietal evoked spikes, benign occipital epilepsy of childhood, migraine/epilepsy syndromes, and epilepsy with bilateral occipital calcification. In addition, occipital and parietal epilepsy may be on the basis of any underlying structural lesion. There is frequently a poor correlation between clinical and EEG features. MRI and functional imaging often reveals underlying pathology. There have been no specific trials of different antiepileptic drugs for occipital and parietal seizures. Surgical treatment has its place, with attention to the risk of causing a fixed neurological deficit.

N170 asymmetry as an index of inferior occipital dysfunction in patients with symptomatic occipital lobe epilepsy

“…Such phenomenon is responsible for the complex ictal manifestations involving diverse brain areas, making it difficult to obtain a clear picture of the overall dynamics and potentially leading to important errors when surgery for epilepsy is considered. With the exception of elementary visual symptoms, which are relatively rare, the clinical manifestations associated with occipital lobe epilepsy are not very informative about the particular area of onset of the epilepsy within the posterior brain (reviewed in Sveinbjornsdottir and Duncan (1993)). Complex visual auras, hallucinations, amaurosis, version of head and eyes, eye blinking, have a poor localizing value and can be obtained by electrical stimulation in both occipital, parietal and temporal lobes (reviewed in Geller et al (2000)).…”

Occipitoparietal Epilepsy, Hippocampal Atrophy, and Congenital Developmental Abnormalities

“…The criteria for inclusion were seizures typical of occipital or parietal origin (6)(7)(8)(9), with radiological or pathological evidence of a congenital developmental abnormality. This encompassed malformations of cortical development and perinatal insults resulting in porencephalic cysts or focal encephalomalacia (1)(2)(3)(10)(11)(12)(13).…”

Clinical Reasoning: Seizures from the neglected lobe

“…Based on epidemiologic studies, the most common etiology for parietal lobe seizures is mass lesions (e.g., gliomas or astrocytomas) followed by birth and postnatal trauma and postinflammatory gliosis. 2 The sulcal effacement in this case could represent a subtle mass effect of a low-grade glioma given the lack of contrast enhancement. An inflammatory (e.g., autoimmune or paraneoplastic) process in the setting of a mild lymphocytic predominant leukocytosis in the initially obtained CSF is possible.…”

“…1 Somatosensory symptoms are the most common auras associated with parietal lobe seizures followed by affective, vertiginous, and visual auras. 2 Both the occipital and parietal lobe are relatively small lobes that are well connected to the ipsilateral frontal and temporal lobe, thalamus, and the supplementary sensorimotor areas (SSMAs). 2 Motor representation in the SSMAs is bihemispheric and these regions are well connected with subcortical structures, which can result in seizures involving unilateral asymmetric tonic posturing of extremities, complex limb movements (e.g., bicycling), and truncal rotation.…”

“…2 Both the occipital and parietal lobe are relatively small lobes that are well connected to the ipsilateral frontal and temporal lobe, thalamus, and the supplementary sensorimotor areas (SSMAs). 2 Motor representation in the SSMAs is bihemispheric and these regions are well connected with subcortical structures, which can result in seizures involving unilateral asymmetric tonic posturing of extremities, complex limb movements (e.g., bicycling), and truncal rotation. 3 The visual phenomena of the patient's seizures could be the result of an occipital seizure and the right sensory aura of a left parietal lobe seizure.…”