Dichotic listening failure in dysphoric neuropsychiatric patients who endorse multiple seizure-like symptoms

Epilepsy spectrum disorders: A concept in need of validation or refutation

Episodic psychiatric symptoms are not uncommon and range from panic attacks to repeated violent acts. Some evidence has accumulated over the years that at least in a subset of patients exhibiting these symptoms there may be evidence for the presence of focal cortical/subcortical hyperexcitability. In these cases the condition could be conceptualized as an epilepsy spectrum disorder (ESD) with significant treatment implications. There is currently no clear demarcation of this category of symptoms, their prevalence, an understanding of how these symptoms occur, what is appropriate work up and possible treatments. In this article, we propose that milder degrees of increased neural excitability (i.e., a subthreshold excitation insufficient to cause seizures) may nonetheless be capable of causing observable phenotypic changes. The observable phenotypic changes depend on the degree of hyperexcitability and the location of the hyperexcitable neural tissue. The location of the abnormal neural tissue may dictate the initial manifestation of an attack resulting from activation of the hyperexcitable tissue, but the anatomical connectivity of the abnormal region will dictate the breadth of manifestations. We provide some evidence, derived mainly from either electroencephalography studies of these populations or clinical reports of response to anti-epilepsy treatment, for the assumption and propose methods to test the advanced hypothesis.

Theta bursts, closed head injury, and partial seizure-like symptoms: a retrospective study

The purpose of this retrospective, chart-review study was to provide additional information on the clinical correlates ofparoxysmal theta activity on EEG and to further examine the previously proposed relation (Varney, Hines, Bailey, & Roberts, 1992) between episodic symptoms in the context of prior closed-head injury and theta bursts. Allparticipants were veterans receiving their health care at a single, tertiary-care, Veterans Affairs medical center. Compared with patients with normal EEGs (comparison group, n = 30) and nonparoxysmal theta-delta slowing (comparison group, n = 30), consecutive patients with theta bursts (n = 38) were found to have significantly more episodic (ie., partial seizure-like) symptoms documented in their medical records. History of closed-head trauma was also associated with increased reporting of episodic symptoms across all three clinical groups. These findings suggest that, in the presence of theta bursts on EEG, clinicians may wish to interview systematicallyfor episodic, partial seizure-like phenomena, especially when paroxysmal theta activity occurs in the context of prior closed head injury.

Complex partial epileptic-like signs contribute differential sources of variance to low self-esteem and imaginings

64 university men and 55 university women displayed correlations (r = 0.40) between two psychometric inventories that have been employed to study subclinical complex partial epileptic-like signs in normal and traumatically brain-injured people. Although psychometric inferences of self-esteem and reports of childhood memories and imaginings were not significantly associated, both indicators of complex partial epileptic-like signs showed significantly positive associations with fantasy-prone behavior but significantly negative correlations with self-esteem. Subsequent analyses supported the vectorial hemisphericity model that elevated mesiobasal limbic activity may enhance imaginings while frequent intrusions into awareness of right-hemispheric indicators would be also associated with lower self-esteem. Lower self-esteem was correlated significantly with reported fears and phobias for the women but not for the men.

Do dichotic word listening asymmetries predict side of temporal lobe seizure onset?

Dichotic word listening asymmetries are thought to be useful in predicting side of temporal lobe dysfunction. However, little direct evidence exists to support this assumption in practice, especially in patients with subtle epileptogenic lesions. To determine if word listening ear asymmetries are valid predictors of side of temporal lobe seizure onset, we examined the preoperative dichotic word listening performance of 80 patients with either left (N = 41) or right (N = 39) temporal lobe (TL) seizure foci. On a group level, patients showed a statistically significant 'lesion effect' as evidenced by a relative deficit in the ear contralateral to the side of lesion. Prediction of side of seizure focus in individual cases, however, was poor: depending upon the criteria used, 61% to 80% of epileptics with unilateral temporal lobe foci did not show the expected contralateral ear deficit. Results suggest that caution be exercised when inferring side of temporal lobe seizure focus through dichotic word listening asymmetries in individual temporal lobe epilepsy cases.

Seizure suggestibility may not be an exclusive differential indicator between psychogenic and partial complex seizures: the presence of a third factor

Differential diagnosis between psychogenic or ('hysterical') pseudoseizures and clinical partial complex seizures has often employed an index or inference of suggestibility. However, recent research indicates a moderate association between complex partial epileptic-like signs and hypnotic capacity in the normal population as well as for complex partial epileptic patients. Consequently, the precipitation of overt, non-stereotyped seizures by instruction may not be a reliable diagnostic method when an insidious process is slowly elevating temporal/limbic lobe lability. Implications for treatment and contra-indication of antipsychotic (D2 antagonist) drugs are discussed.

Complex partial epileptic signs as a continuum from normals to epileptics: normative data and clinical populations

Over a 10-year period, a total of 447 men and 624 women between 18 and 61 years of age were administered an inventory whose items describe experiences that are similar to those evoked by electrical stimulation of the temporal lobes. Empirically determined factors contained experiences of sensory enhancement, affective-dissociation, ego alien intrusions, and literary emphasis. Using this population as a reference, T scores for these clusters were calculated for special normal populations (poets, drama students, false pregnancies) and for clinical groups (post-traumatic stress, anxiety-depersonalization, exotic dissociations, and complex partial epilepsy). Whereas only mild elevations (50 < T < 65) in indicators of temporal lobe signs and symptoms were noted in the special groups, moderate (65 < T < 75) and severe (T > 79) elevations were noted in the clinical populations.

Neuropsychiatric correlates of theta bursts in patients with closed head injury

Twenty-five head-injured patients with localized theta bursts on standard or 24 h ambulatory EEG were administered a standardized interview for neuropsychiatric symptoms associated with complex partial seizures (e.g. olfactory hallucinations, memory gaps) and a battery of neuropsychological tests. Although the formal neuropsychological test performances of these patients were relatively normal they reported an abundance of seizure-like behavioural symptoms. While the frequency of these symptoms was high, they did not occur in a stereotyped complex or sequence. These findings suggest that localized theta bursts may be diagnostic of an underlying neuroelectrical disorder.

The phenomenology of multiple partial seizure-like symptoms without stereotyped spells: an epilepsy spectrum disorder?

Consistent with previous reports by neuropsychiatrists, the results of the present investigation confirmed the existence of a neurobehavioral disorder characterized by the subjective experiencing of multiple cognitive, affective, and psychosensory phenomena similar to those associated with more classic partial seizure disorders. According to the literature, such patients typically respond favorably to anticonvulsants although they lack the customary motor manifestations of complex partial seizure (CPS) disorders and typically do not have stereotyped spells. This neuropsychiatric syndrome has recently been termed epilepsy spectrum disorder (ESD). In the present study, 30 patients with ESD were matched with equal numbers of treatment-refractory CPS patients and normal controls. All subjects were administered a standardized interview consisting of 35 cognitive, affective, and psychosensory partial seizure-like symptoms. The results indicated that ESD patients endorsed significantly more partial seizure-like symptoms than did CPS patients and controls. Relatively low levels of symptom endorsement by an unmatched psychiatric comparison sample indicated that the high levels of symptom endorsement by ESD patients could not be attributed to the presence of psychiatric dysfunction per se. Analysis of responding to 'foil' items unrelated to partial seizures indicated that high levels of symptom endorsement by ESD patients did not merely reflect a deviant response. Although ESD patients seldom present themselves at tertiary care epilepsy centers, the study of such patients is likely to be of relevance to mainstream epileptology.

Left ear (right temporal lobe) suppressions during dichotic listening, ego-alien intrusion experiences and spiritualistic beliefs in normal women

Beliefs in spiritualism, a history of a sensed presence, and mental diplopia may share a common source of psychometric variance. We hypothesized that this variance should be specifically associated with right temporal-lobe function. Inferences of temporal lobe signs, hemisphericity (Vingiano's quotient) and self-esteem as well as dichotic listening measures were obtained for 26 university women. As predicted, the numbers of left-ear suppressions (right temporal-lobe function) but not of right-ear suppressions were specifically and moderately (rho = 0.64) correlated with the intensity of Tobacyk's spiritualistic beliefs and a history of sensed presences and ego-alien intrusions. However, the negative association (rhos about -0.45) between indices of left-right hemisphericity and self-esteem was related to a separate factor.