PATIENTS WITH VERY MILD DEMENTIA MAY BE ABLE TO DRIVE SAFELY

Greater severity of dementia, increased age, and lower education were associated with higher rates of failure or marginal performance on driving tests in patients with very mild to mild dementia, researchers reported in the January 23 online Neurology.

Brian R. Ott, MD, Director of the Alzheimer’s Disease and Memory Disorders Center at Rhode Island Hospital and Professor of Clinical Neuroscience at Brown University in Providence, and colleagues assessed 128 drivers ages 40 to 90 for dementia; 44 had a Clinical Dementia Rating (CDR) of 0 (controls), 52 had very mild dementia (CDR, 0.5), and 32 had mild dementia (CDR, 1). Of the participants with dementia, 61 were diagnosed with probable Alzheimer’s disease, and 23 had possible Alzheimer’s disease. Subjects were evaluated by a driving instructor on a standardized road test and completed assessments of cognitive, neurologic, visual, and physical function at baseline. The participants with dementia repeated the testing every six months, while controls repeated the testing only at 18 months.

Dr. Ott’s team found that 57% of controls and 19% of participants with Alzheimer’s disease were judged to be safe drivers at 18 months. “Control and patient groups both declined in performance,” stated the researchers, although “as expected, patients were more likely to fail the road test than controls.” During the entire study period, participants with mild dementia were also more likely to fail than were patients with very mild dementia (hazard ratio, 3.51), and their median time to failure was twice as fast (324 vs 605 days).

Patient age and education level also predicted road test failure. “The hazard of failure increased by about 6% for every year by which a subject’s age exceeded the average age of the patient group (75.7 years), and by about 10% for every year by which the subject’s schooling lagged the average educational level of the patient group (13.9 years),” reported the researchers. Rates of traffic accidents and violations, based on self-report and checked against motor vehicle accident registries, did not differ significantly between the groups after correction for miles driven.

Dr. Ott and colleagues noted that prior research has found that persons with mild dementia can pass a road test despite being hazardous drivers. “Patients with very mild Alzheimer’s disease (ie, CDR, 0.5) can continue to drive safely for an extended period of time, and … greater efforts need to be focused on identifying the specific demographic, behavioral, and cognitive factors that are associated with risky driving in this population,” the investigators concluded.

Suggested Reading
Ott BR, Heindel WC, Papandonatos GD, et al. A longitudinal study of drivers with Alzheimer disease. Neurology. 2008 Jan 23; [Epub ahead of print].

NONFOCAL TRANSIENT NEUROLOGIC ATTACKS MAY BE MORE HARMFUL THAN PREVIOUSLY THOUGHT

Patients who experience nonfocal transient neurologic attacks (TNAs), and especially those with mixed TNAs, have an increased risk of stroke, ischemic heart disease, and dementia, contrary to previous studies, according to a report in the December 26, 2007, JAMA.

Michiel J. Bos, MD, and colleagues from Erasmus Medical Center, Rotterdam, the Netherlands, analyzed the risk of first TNA and subsequent adverse events in 6,062 participants 55 and older (median age, 67.7; 62% women) from the Rotterdam Study who were free from stroke, myocardial infarction, and dementia at baseline (1990-1993). Subjects were continuously monitored for stroke, transient ischemic attack, ischemic heart disease, dementia, and death until January 1, 2005.

During 60,535 person-years, 548 participants developed TNA: 282 were focal (4.7 per 1,000 person-years), 228 were nonfocal (3.8 per 1,000 person-years), and 38 were mixed (0.6 per 1,000 person-years). There were also 619 strokes, 848 diagnoses of ischemic heart disease, and 662 vascular deaths.

Participants with focal TNA had a higher risk of subsequent stroke (hazard ratio [HR], 2.14) and ischemic stroke (HR, 2.61) than participants without TNA but had an equal risk of ischemic heart disease and dementia, reported the researchers. The risk of stroke within 90 days of focal TNA was 3.5%. Participants with nonfocal TNA also had a higher risk of stroke (HR, 1.56) and dementia (HR, 1.59)—especially vascular dementia (HR, 5.05)—compared with those without TNA. Participants with mixed TNA also had increased risks of overall and ischemic stroke (HRs, 2.48 and 2.99, respectively), ischemic heart disease and myocardial infarction (HRs, 2.26 and 3.34, respectively), vascular death (HR, 2.54), and dementia and vascular dementia (HRs, 3.46 and 21.5, respectively).

Dr. Bos and colleagues noted that few studies have challenged or verified the benign clinical course of nonfocal TNA. “Our findings challenge the strong but unfounded conviction that nonfocal TNAs are harmless,” they said. They also suggested further research into the potential increased risk of ischemic heart disease in patients with mixed TNA.

Suggested Reading
Bos MJ, van Rijn MJ, Witteman JC, et al. Incidence and prognosis of transient neurological attacks. JAMA. 2007;298(24):2877-2885.

LOW-CARBOHYDRATE DIET MAY HELP PATIENTS WITH INTRACTABLE EPILEPSY

A modified Atkins diet may reduce seizure frequency in patients with intractable epilepsy, especially those with a high initial seizure frequency and those who lose more weight on the diet, according to a report in the February Epilepsia.

The prospective open-label study was conducted from November 2004 to November 2006 in 30 patients (19 women) ages 18 to 53 by Eric Kossoff, MD, Assistant Professor of Neurology and Pediatrics at the Johns Hopkins University School of Medicine in Baltimore, and colleagues. Patients had experienced at least one seizure per week and had tried at least two anticonvulsant medications. The participants were evaluated at baseline and instructed to restrict carbohydrate intake to 15 g/day, eat high-fat foods, and take a daily multivitamin and calcium supplement; fluids and calories were not restricted. They self-reported seizures, urine ketones, and weight on a semiweekly or weekly basis.

At evaluations after one, three, and six months on the diet, 14, 13, and nine participants, respectively, had a seizure reduction of greater than 50%; at three and six months, one participant was seizure-free. The median time to improvement in the 18 individuals who experienced any improvement was two weeks. The four people with the highest initial seizure frequency were the best responders at one month, with at least a 76% seizure reduction, although the researchers noted that the difference became less pronounced during the subsequent five months. By three months, 43% of the participants with fewer than 20 initial seizures per week experienced more than 50% improvement. Other patient characteristics did not predict diet response.

All 28 patients who were on the diet for at least one week became ketotic, reported Dr. Kossoff and colleagues. At one month, 10 of 16 participants with moderate to large ketosis had a seizure reduction greater than 50%, compared with three of 10 with small or less ketosis. Of 12 participants who increased their carbohydrate intake to 20 g at either one or three months, none reported a worsening of seizures or ketosis.

Twelve participants reduced their caloric intake; those with a seizure reduction of more than 50% did so by a median 446 calories per day, versus 352 calories per day in those with less than 50% seizure reduction. Twenty-two participants with at least one follow-up visit lost weight, and the researchers noted “a higher likelihood of > 50% response at three months … in those with greater than the median BMI decrease of –0.9.” However, two of three subjects whose BMI increased during the study experienced the same reduction, they said.

Suggested Reading
Kossoff EH, Rowley H, Sinha SR, Vining EP. A prospective study of the modified Atkins diet for intractable epilepsy in adults. Epilepsia. 2008;49(2):316-319.

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