LETTERS

Driving and Alzheimer’s Disease Harold N. Mozar, MD, and James T. Howard, MS

In his thought-provoking editorial entitled “Who May Drive? Who May Not? Who Shall Decide?” Drachman [l] may have created the impression that in California the driv- ing licenses of patients with Alzheimer’s disease (AD) are automatically revoked when their names are reported by physicians to the Department of Motor Vehicles. It is true that physicians are now required to report patients with AD and related disorders under California law [2]. However, an evaluation of the patient’s driving competence follows the receipt of each physician’s report, and a final decision is then made concerning motor vehicle licensure.

We are not in conflict with the editorial‘s insistence that “limitation of the privilege to drive should be based on dem- onstration of impaired driving competence . . .” El]. Drachman suggests that when driving incompetence of patients with AD and other neurodegenerative disabilities is not obvious, the competence can be determined by testing in an appropri- ate environment. This is our approach in California. The Department of Motor Vehicles determines driving compe- tence by reviewing detailed information provided by the pa- tient’s physician, by a face-to-face interview, and when neces- sary, by testing under controlled conditions.

Alzheimer’s Disease Program Adult Health Section California Department of Health Services Sacramento, CA

References 1. Drachman DA. Who may drive? Who may not? Who shall de-

2. Title 17, California Code of Regulations, Section 2572, Chapter cide? Ann Neurol 1988;24:787-788

321, Statutes of 1987

Driving and Alzheimer’s Disease Paul Deiter, MD, and Sheldon Wolf, MD

In an editorial published in the December 1988 issue, Drachman 111 comments on recent California legislation as follows:

California has recently enacted a law requiring physicians to report all patients with AD or related disorders, with the supposition that such patients will lose the privilege of driving.

We believe the recent California law is simply an extension of preexisting statutes. To demonstrate this, a discussion of the reporting requirement in California is necessary.

In 1965 the California legislature amended Health and Safety Code $410 as follows:

The State Department of Health Services shall define disorders characterized by lapses of consciousness for the purposes of the reports hereinafter referred to:

(1) All physicians shall report immediately to the local health officer in writing the name, date of birth, and ad- dress of every person diagnosed as a case of a disorder characterized by lapses of consciousness.

(2) The local health officer shall report in writing to the state department the name, age, and address of every per- son reported to it as a case of a disorder characterized by lapses of consciousness.

( 3 ) The state department shall report to the State De- partment of Motor Vehicles the names, dates of birth, and addresses of all persons reported as a case of a disorder characterized by lapses of consciousness by the physicians and local health officers.

( 4 ) Such reports shall be for the information of the State Department of Motor Vehicles in enforcing the provisions of the Vehicle Code of California, and shall be kept confi- dential and used solely for the purpose of determining the eligibility of any person to operate a motor vehicle on the highways of this state.

In 1966 the Department of Health published the follow- ing regulation as Title 17 $2572 of the California Adminis- trative Code:

As required in Section 410 of the Health and Safety Code, the definition as to what shall constitute a reportable case of a disorder characterized by lapses of consciousness shall be as follows:

Any person aged 14 years or older who during the preceding three years has experienced, on one or more occasions, either a lapse of consciousness or an episode of marked confusion, caused by any condition which may bring about recurrent lapses, including momentary lapses of consciousness or episodes of marked confusion, shall be considered to have a disorder characterized by lapses of consciousness and shall be reportable.

The definition includes, but is not limited to persons subject to lapses of consciousness or episodes of marked confusion resulting from neurological disorders, senility, daa- betes mellitus, cardiovascular disease, alcoholism or excessive use of alcohol sufficient to bring about bhckouts (retrograde amnesia for their activities while drinking). {Emphasis added.)

This statutory and regulatory scheme has persisted substan- tively unchanged. It requires that the patient have (1) either a lapse of consciousness or an episode of marked confusion (2) caused by any condition which may bring about recurrent lapses. A list of some of the conditions likely to cause recur- rent lapses is given in the regulation.

The existence of the law and regulation has not resulted in the loss of driving privileges for all or substantially all pa- tients with these common disorders. Only those who fit the definition given above are reported. The report triggers an evaluation of the individual. There may be a temporary sus- pension of driving privileges during this evaluation.

In 1987 the California legislature amended Health and Safety Code $410 to add:

Copyright 0 1989 by the American Neurological Association 289

(e) The state department shall define disorders charac- terized by lapses of consciousness for purposes of this section and shall include Alzheimer’s disease and related disorders in the definition.

This provision does no more than state that Alzheimer’s disease must be specifically mentioned in the definition of disorders characterized by lapses of consciousness. Since the Department of Health already lists a number of conditions in Title 17 82572, the practical effect should be to add Alz- heimer’s disease and related disorders to the list when the regulation is updated. The same determinations still must be made by the physician. Does the patient have (1) either a lapse of consciousness or an episode of marked confusion (2) caused by any condition which may bring about recurrent lapses?

Thus the law implicitly acknowledges the difficulty to which Drachman alludes of precisely defining the amount of cognitive impairment which might make driving hazardous. It leaves to the attending physician the decision on report- ability. In this respect, there has been no change since 1966.

Kaiser Permanente Southern California Pemanente Medical Group Pasadena, CA

R&yence 1. Drachman DA. Who may drive? Who may not? Who shall de-

cide? Ann Neurol 1988;24:787-788

Right-Hemisphere Speech, Callosal Size, Perinatal Brain Insult, and Schizophrenia H. A. Nasrallah, MD

In their article titled “The Corpus Callosum Is Larger with Rght-Hemisphere Cerebral Speech Dominance,” OKusky and associates [l) may provide an important clue to the pathogenesis of corpus callosum enlargement in schitophre- nia.

Rosenthal and Bigelow [2) first reported an increased thickness of the corpus callosum in a postmortem sample of schizophrenic subjects. This finding was replicated by Bigelow and colleagues 131, who also found that the thicken- ing was particularly noticeable in the anterior part of the body of the callosum, immediately posterior to the genu. Nasrallah and coworkers 141 conducted a quantitative histo- logical study of the callosum in the sample of Bigelow and associates [3] and found no differences in the number of callosal fibers or glial cells (per unit area) between the schizo- phrenic and control groups. A magnetic resonance imaging study by Nasrallah and colleagues ( 5 ) showed that the corpus callosum was significantly thicker in schizophrenic women than in female control subjects (no differences were found in male subjects) and that, in contrast to the findings of Witel-

son [6), the corpus callosum was not larger in left-handed subjects [73.

Many researchers have speculated about the cause and significance of a large callosum in schizophrenia, but with the report of OKusky and coworkers [I], speculation may take a new twist and a testable hypothesis may be generated. If a larger callosum is associated with right-hemisphere speech, could there be a higher frequency of right-hemisphere speech in schizophrenia? Could the formal thought disorder present in many nonparanoid schizophrenics be related to right-hemisphere language or to poorly integrated bilateral hemispheric speech due to left-hemisphere dysfunction {S}?

There is now a substantial body of evidence that perinatal brain insult may be an important factor in impaired neu- rodevelopment in schizophrenia [9), with disruption of cell proliferation and migration or cell death and axonal elimina- tion. The speculation by O’Kusky and associates El) that perinatal brain injury may produce right-hemisphere speech is certainly relevant to schizophrenia and may explain why the corpus callosum tends to be thicker in some patients with schizophrenia. An excess of callosal interhemispheric fibers in adulthood due to disrupted elimination processes during development may also be related to the pathophysiology of schneiderian delusions in schizophrenia, as hypothesized by Nasrallah [lo).

Intracarotid amobarbital studies to determine hemispheric speech dominance in schizophrenia are obviously needed to test the validity of the hypothesis that increased callosal size in schizophrenia is associated with right-hemisphere speech and perinatal hypoxia.

The Ohio State University College of Medicine Columbus. OH

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OKusky J, Strauss E, Kosaka B, et al. The corpus callosum is larger with rght-hemisphere cerebral speech dominance. Ann Neurol 1988;24:379-383 Rosenthal R, Bigelow LB. Quantitative brain measurements in chronic schizophrenia. Br J Psychatry 1972;121:259-264 Bigelow LB, Nasrallah HA, Rauscher FP. Corpus callosum thickness in chronic schizophrenia. Br J Psychiatry 1983;142:

Nasrallah HA, McCalley-Whitrers M, Bigelow LB, et al. A his- tological study of the corpus callosum in chronic schizophrenia. Psychiatry Res 1983;8:25 1-260 Nasrallah HA, Andreasen NC, Coffman JA, et al. A controlled magnetic resonance imaging study of corpus callosum thickness in schizophrenia. Biol Psychiatry 1986;2 1:274-282 Witelson SF. The brain connection: the corpus callosum in larger left handers. Science 1985;229:665-668 Nasrallah HA, Andreasen NC, Coffman JA, et al. The corpus callosum is not larger in left handers. SOC Neurosci Abstr 1986;12:720 Nasdah HA. Is schizophrenia a left hemisphere disease? In: Andreasen NC, ed. Can schizophrenia be localized in the brain? Washington DC: American Psychiatric Press, 1986353-74 McNeil TF. Obstetric factors and perinatal injuries. In: Tsuang MT, Simpson JC, eds. Nosology, epidemiology and genetics of schizophrenia Amsterdam: Elsevier Science Publishers B.V., 1988:319-344 (Nasrallah HA, ed. Handbook of Schizophre- nia, vol 111)

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