Possible Temporal Lobe Symptoms

VERNON M NEPPE MD, PhD(Med)

Seizure disorders with behavioral disturbance, may initially be interpreted as psychiatric in origin. Many such problems relate to the temporal lobe of the brain. The features of temporal lobe epilepsy and non-epileptic dysfunction of the temporal lobe are so varied and so protean that it is necessary to classify them. I have suggested the term "Possible temporal lobe symptoms" (PTLSs) relate to features which can be induced by stimulating areas of the temporal lobe during neurosurgery. These symptoms only become specific symptoms of temporal lobe dysfunction if their occurrence is validated empirically during a seizure - either through observation or by the electroencephalogram (hence the word "possible" in possible temporal lobe seizures). Great care must be taken in interpretation of such features : For example, using a phenomenological analysis, I demonstrated that the symptom of deja vu commonly regarded as symptomatic of temporal lobe epilepsy indeed had a very special phenomenologic quality in patients with temporal lobe epilepsy. Like many other such focal symptoms, this involves its association with post-ictal features such as sleepiness, headache and clouded consciousness and its link in time with these features. This association provides an excellent clue to the existence of temporal lobe epilepsy. However, deja vu is a normal phenomenon occurring in 70 percent of the population and unless such phenomenological detail is obtained, patients' symptomatology may be misinterpreted. I similarly studied olfactory hallucinations but a specific type of temporal lobe epilepsy olfactory hallucination could not be demonstrated although there were suggestive features. A major message, therefore, may be the relevance of adequately assessing the symptomatology of patients presenting with epilepsy. It may be that this is a direction as relevant as electroencephalographic monitoring. Most of all it reminds us how slender our interpretations of other related but different symptoms such as "he experiences strange smells" might be and the fact that it is critical to elicit whether these are episodic in quality and linked with other symptomatology particularly epileptic or temporal lobe. A written test instrument designed to screen for such symptoms which I use in clinical practice is the INSET - The INVENTORY OF NEPPE OF SYMPTOMS OF EPILEPSY AND THE TEMPORAL LOBE (INSET). The INSET involves screening for possible temporal lobe, epileptic and organic symptoms and spells. Thereafter the symptoms are categorized into several headers namely nonspecific symptoms, possible and controversial temporal lobe symptoms, seizure related and other focal features. The test is based on the subject and / or his family responding to questions which are thereafter elaborated in greater clinical detail. Responses are at two time levels: current as well as the most common frequency in the remote past and require the patient to rank frequency from never through less than yearly to more than daily (i.e. 0-6). Questions in the INSET have been based on the earlier Neppe Temporal Lobe Questionnaire which itself derived from an intensive literature review on the topic. The INSET plus medical history is a major determining factor for whether to order follow-up specialized electroencephalograms such as ambulatory EEG.

TABLE: POSSIBLE TEMPORAL LOBE SYMPTOMS (PTLSs)

Controversial PTLSs (CPTLSs)

Not Necessarily Disintegrative PTLSs (NPTLSs)

Symptoms Not Necessarily Requiring Treatment Paroxysmal (Recurrent) Episodes of:

Any form of:

1. Auditory perceptual abnormality;
2. Olfactory hallucinations;
3. Gustatory hallucinations;
4. Rotation or disequilibrium feelings linked to other perceptual qualities;
5. Unexplained "sinking," "rising," or "gripping" epigastric sensations;
6. Flashbacks;
7. Illusions of distance, size (micropsia, macroscopy), (micropsia), loudness, tempo, strangeness, unreality, fear, sorrow;
8. Hallucinations of indescribable modality.
9. Temporal lobe epileptic deja vu (has associated ictal or postictal features {headache, sleepiness ,confusion} linked to the experience in clear or altered consciousness )
10. Any CPTLSs which appear to improve after administration of an anticonvulsant agent such as carbamazepine.

Disintegrative PTLSs (DPTLSs)

Symptoms Requiring Treatment: Paroxysmal (Recurrent) Episodes of:

Seizure related features ( SZs )

Any typical absence, tonic or clonic or tonic-clonic or bilateral myoclonic seizures in the absence of metabolic, intoxication or withdrawal related phenomena.

Clearly there is a greater need to pay attention to unusual episodic symptoms. This will ultimately lead to a workable classification and the recognition that certain seizure like features need be treated by psychiatrists.