Amyotrophic lateral sclerosis in Olmsted County,Minnesota, 1925 to 1998

The authors sought to determine trends in the incidence of ALS in Olmsted County from 1925 to 1998. Seventy-seven cases of ALS were identified during the period studied. The incidence rate remained stable at 1.7 cases per 100,000 people per year. Mean age at onset was 63 years. Mean survival was 23 months from diagnosis. Mean survival for patients <60 years old was 31 months; for patients aged >or=60 years, it was 20 months (p = 0.02). Mean time from symptom onset to diagnosis was 13 months. Neither survival nor time to diagnosis changed significantly over time.     

Survival study of Parkinson disease in Olmsted County,Minnesota

OBJECTIVE: To compare survival in incident cases of Parkinson disease (PD) with survival in subjects free of PD from the general population. METHODS: We used the medical records linkage system of the Rochester Epidemiology Project to identify incident cases of PD in Olmsted County, Minnesota, for the period 1976-1995. Cases were matched by age and sex to referent subjects from the same population. For 196 cases and 185 referent subjects, we studied survival between the date of diagnosis of PD (or index date) and death, loss to follow-up, or end of the study (May 1, 2000). RESULTS: The median length of follow-up was 7.2 years for cases and 8.0 years for referent subjects; 110 patients with PD and 79 referent subjects died during follow-up. The median survival was 10.3 years in cases and 13.4 years in referent subjects. The relative risk (RR) of death was 1.60 (95% confidence interval [CI], 1.20-2.14; P =.002) overall, 1.81 (95% CI, 1.15-2.84; P =.01) in women, and 1.49 (95% CI, 1.01-2.20; P =.04) in men. There was a decreasing trend in the RR of death according to age at onset of PD (in tertiles): younger than 67 years, RR, 2.04 (95% CI, 0.99-4.19; P =.05); 67 to 76 years, RR, 1.76 (95% CI, 1.08-2.86; P =.02); and older than 76 years, RR, 1.48 (95% CI, 0.95-2.29; P =.08). Patients with PD who had both rest tremor and pronounced asymmetry had a better prognosis than patients with neither clinical characteristic. Patients with PD who smoked survived better than expected. CONCLUSIONS: Patients with PD face a higher risk of death compared with subjects free of PD from the general population. Certain clinical characteristics and smoking modify survival.     

Late effects of paralytic poliomyelitis in Olmsted County, Minnesota

We identified a cohort of 300 individuals who had paralytic polio between 1935 and 1955. All lived in Olmsted County, Minnesota. From the 247 survivors, we selected 50 subjects for detailed historical, functional, psychological, clinical, and electrophysiologic evaluation. Sixty-four percent of these 50 survivors complained of new symptoms of muscle pain, fatigue, and weakness after a period of prolonged stability. This led to changes in lifestyle or activity in only 18%. The likelihood of expressing new complaints was not related to present age or interval since polio, and electrophysiologic testing did not distinguish between those with or without new problems. The development of new difficulties in a limb was most strongly predicted by significant paralysis of that limb at the time of the acute illness. Patients with leg weakness were twice as likely to complain of new problems compared to those with arm weakness. Elevated creatine kinase levels were present only in those with new complaints.     

Incidence of Acute Symptomatic Seizures in Rochester, Minnesota, 1935-1984

Summary We determined the incidence of seizures due to acute CNS insults for residents of Rochester, Minnesota, U.S.A., from 1935 though 1984. The age-adjusted incidence rates for 1955–1984, the period of most complete case ascertainment, was 39.0/100,000 person-years (United States 1970 population as standard). The age-adjusted incidence was considerably higher in men: 52.0 as compared with 29.5 in women. The 3.6% risk of experiencing an acute symptomatic seizure in an 80-year lifespan approaches that of developing epilepsy. The major causes of acute symptomatic seizures were traumatic brain injury, cerebrovascular disease, drug withdrawal, and CNS infections. Each type of acute symptomatic seizure has age, gender, and time period patterns that reflect the occurrence of the underlying cause.     

Incidence of epileptic syndromes in Rochester, Minnesota: 1980-1984

PURPOSE: To determine the incidence and the distribution of epileptic syndromes in a well-defined population. METHODS: By using the records-linkage system of the Rochester Epidemiology Project, we screened all the residents of Rochester, Minnesota, who received a diagnosis of seizures, convulsions, or epilepsy from 1980 through 1984. One hundred fifty-seven residents with incident epilepsy (recurrent unprovoked seizures) were classified by using the International League Against Epilepsy (ILAE) Classification of the Epilepsies and Epileptic Syndromes. Residents with special syndromes were excluded. With a pretested algorithm, patients were classified at three levels of specification: major syndromic groups (e.g., localization-related syndromes), syndromic subgroups (e.g., idiopathic epilepsy with age-related onset), and whenever possible, individual syndromes. RESULTS: All but one patient were classified into major syndromic groups and subgroups. The annual age-adjusted incidence per 100,000 population was 52.3 cases (34.9 for localization-related epilepsies; 7.7 for generalized epilepsies; 9.7 for undetermined epilepsies). Incidence was 0.2 for idiopathic, 17.2 for cryptogenic, 17.5 for symptomatic localization-related epilepsies, 3.7 for idiopathic, 1.7 for symptomatic or cryptogenic (age-related), and 2.3 for symptomatic (non age-related) generalized epilepsies. CONCLUSIONS: With the exception of idiopathic epilepsies, the incidence of the major syndromic categories in our study was higher than that provided by previous population-based studies.     

Tuberous sclerosis complex in Olmsted County, Minnesota, 1950-1989

The incidence of tuberous sclerosis complex in Olmsted County, Minnesota, was 0.28 per 100,000 person-years from 1950 through 1989, the point prevalence on December 31, 1989, was 6.9 per 100,000 persons, and the incidence at birth was 6.0 per 100,000 live births. The incidence was 0.13 per 100,000 person-years from 1950 through 1974 and 0.46 per 100,000 person-years from 1975 through 1989. The higher rate of diagnosis during the later period is believed to be due to the use of computed tomography. Of the 12 patients considered in this study, one patient presented with seizures and severe intellectual disability, six patients presented with seizures, three patients presented with multiple facial angiofibroma, and two patients were asymptomatic.     

Time trends in the incidence of parkinsonism in Olmsted County, Minnesota

OBJECTIVE: To investigate time trends in the incidence of parkinsonism and PD over a 15-year period (1976 to 1990). METHODS: The authors used the medical records-linkage system of the Rochester Epidemiology Project to identify incidence cases of parkinsonism in Olmsted County, MN, over three 5-year periods, 1976 to 1980, 1981 to 1985, and 1986 to 1990. PD and other types of parkinsonism were classified using defined criteria. Population denominators were derived from census data and were corrected by removing prevalent cases of parkinsonism. RESULTS: Over the 15 years of the study, 364 cases of parkinsonism were identified; 154 (42%) of them had PD. The incidence of parkinsonism remained stable over the three 5-year periods for the age classes 0 to 39, 40 to 59, and 60 to 69 years. For the age class 70 to 99 years, there was some increase over time mainly owing to an increased incidence of drug-induced parkinsonism. The incidence of PD remained stable over the three 5-year periods for all age classes. Results were similar when considering men and women separately. No birth-cohort effect was present for parkinsonism. Comparison with three previous studies in the same population did not reveal any major long-term secular trends in the incidence of parkinsonism. CONCLUSIONS: The findings for PD over 15 years and comparison of the findings with historical data for parkinsonism over half a century suggest that no major environmental risk factors for PD (e.g., environmental toxins, drugs, diet constituents, or infectious agents) were introduced or removed from this population during these periods.     

Morbidity of Nonfebrile Status Epilepticus in Rochester, Minnesota, 1965–1984

Summary: Purpose : To analyze the nonfatal adverse events (AE) associated with a first episode of status epilepticus (SE).
Methods : We performed a population-based retrospective cohort study to determine the morbidity of SE. Participants included 184 residents of Rochester, Minnesota who experienced nonfebrile SE between 1965 and 1984.
Results : The etiology of SE was acute symptomatic in 100 patients and unprovoked in 84 patients. The most common seizure-types were continuous partial (n = 56, 30%), generalized convulsive (n = 52, 28%). and generalized with focal features (n = 32, 17%). Morbidity related to SE was noted in 5 of the 146 patients (3.4%) surviving 30 days. The AE included hemiparesis (n = 3), encephalopathy (n = 2), mental retardation (n = l), and aphasia (n = 1). All patients with morbidity had an acute symptomatic (n = 4) or remote symptomatic (n = 1) etiology. Thirty-four patients (18.5%) had a second episode of SE.
Conclusions : Based on this retrospective study, significant morbidity related to SE is uncommon and is associated with the underlying etiology.     

Incidence and distribution of parkinsonism in Olmsted County, Minnesota, 1976-1990

OBJECTIVE: Limited information is available on the frequency and distribution of parkinsonism as a syndrome. We studied the incidence of parkinsonism and its specific types among residents of Olmsted County, MN, for the period from 1976 through 1990. METHODS: We used the medical records linkage-system of the Rochester Epidemiology Project to identify all individuals whose records contained documentation of any form of parkinsonism, related neurodegenerative diseases, or tremor of any type. A nurse abstractor screened the records, and, when applicable, a neurologist reviewed them to determine the presence of parkinsonism using specified diagnostic criteria and to define the year of onset. RESULTS: We found 364 incident cases of parkinsonism: 154 with PD (42%), 72 with drug-induced parkinsonism (20%), 61 unspecified (17%), 51 with parkinsonism in dementia (14%), and 26 with other causes (7%). The average annual incidence rate of parkinsonism (per 100,000 person-years) in the age group 50 to 99 years was 114.7; incidence increased steeply with age from 0.8 in the age group 0 to 29 years to 304.8 in the age group 80 to 99 years. The cumulative incidence of parkinsonism assuming no competing causes of death was 7.5% to age 90 years. PD was the most common type of parkinsonism, followed by parkinsonism in dementia in men and drug-induced parkinsonism in women. Men had higher incidence than women at all ages for all types of parkinsonism except drug-induced. CONCLUSIONS: Parkinsonism is a common disease among the elderly; its incidence increases steeply with advancing age and is consistently higher in men. The distribution by type changes with age and gender.     

Incidence and clinical features of trigeminal neuralgia, Rochester, Minnesota, 1945-1984

The overall crude incidence rate of trigeminal neuralgia per 100,000 population in Rochester, Minnesota, for 1945 through 1984 was 4.3 for both sexes combined. The age-adjusted (to total 1980 US population) rate for women (5.9) was significantly higher than that for men (3.4). Annual incidence rates increased significantly with age in both women and men. Data based on evidence in the medical records suggest that trigeminal neuralgia is a rather rare and unpredictable disease: The number of episodes varies from 1 to 11, and length of episode from 1 day to 4 years. This study indicates an elevated relative risk associated with hypertension (both overall and among women in the cohort). Also, prevalence of multiple sclerosis was significantly greater among the group of 75 patients who had trigeminal neuralgia. Since the data on treatment in this study do not correspond to a randomized clinical trial, they are presented as empirical results only and show no single treatment of choice for trigeminal neuralgia.     

Incidence of Epilepsy and Unprovoked Seizures in Rochester, Minnesota: 1935–1984

Summary: The incidence of epilepsy and of all unprovoked seizures was determined for residents of Rochester, Minnesota U.S.A. from 1935 through 1984. Ageadjusted incidence of epilepsy was 44 per 100,000 personyears. Incidence in males was significantly higher than in females and was high in the first year of life but highest in persons aged ≥75years. Sixty percent of new cases had epilepsy manifested by partial seizures, and two thirds had no clearly identified antecedent. Cerebrovascular disease was the most commonly identified antecedent, accounting for 11% of cases. Neurologic deficits from birth, mental retardation and/or cerebral palsy, observed in 8% of cases, was the next most frequently identified preexisting condition. The cumulative incidence of epilepsy through age 74 years was 3.1%. The age-adjusted incidence of all unprovoked seizures was 61 per 100,000 person-years. Age-and gender-specific incidence trends were similar to those of epilepsy, but a higher proportion of cases was of unknown etiology and was characterized by generalized onset seizures. The cumulative incidence of all unprovoked seizures was 4.1% through age 74 years. With time, the incidence of epilepsy and of unprovoked seizures decreased in children and increased in the elderly.     

A reappraisal of the epidemiology of multiple sclerosis in Olmsted County, Minnesota

A review of multiple sclerosis (MS) case reports, using the unified record system at the Mayo Clinic for the Olmsted County population, revealed age- and sex-adjusted prevalence rates per 100,000 persons of 160 for Olmsted County and 173 for Rochester, Minnesota, on January 1, 1985. The annual age- and sex-adjusted incidence rate per 100,000 person-years from 1975 to 1984 for Olmsted County was 6.2 and for Rochester, 6.3. This incidence rate is significantly higher than what had been reported previously in Rochester (3.6/100,000) or in other communities. The estimated 25-year survival of the MS population was 76.2% +/- 4.5% compared with 87.7% for the general US white population of a similar age and sex. Survival for men was less than for women. There was no increase in survival for patients diagnosed with MS in more recent decades. No significant increase was found in cancer or autoimmune disease rates in the MS patients.     

Autopsy patterns for Parkinson's disease and related disorders in Olmsted County, Minnesota.

Using a records-linkage system, we determined the frequency and distribution of brain autopsies in residents of Olmsted County, Minnesota, in whom parkinsonism developed during 1976 through 1990. Of the 364 incident cases identified, 235 patients were deceased at the time of record abstraction. The overall autopsy rate was low (23%). Diagnostic certainty (for PD), diagnostic type (PD versus other parkinsonism), sex, age at death, and location at death were important selection factors for autopsy.     

Incidence and clinical features of glossopharyngeal neuralgia, Rochester, Minnesota, 1945-1984.

The annual crude incidence rate of glossopharyngeal neuralgia per 100,000 population in Rochester, Minn., for 1945 through 1984, was 0.7 for both sexes combined, suggesting that glossopharyngeal neuralgia is a rare disease. There were no significant differences between the sexes (p greater than 0.10) in the overall age-adjusted (to the total 1980 US population) rates: 1.1 for men and 0.5 for women. Overall age-specific crude rates increased slightly with age. Our results and conclusions, achieved by comparing our data with a large referral study at Mayo Clinic, suggest that glossopharyngeal neuralgia is generally a mild disease, since mild attacks are not uncommon, the average annual recurrence rate for a second episode is low (3.6%), and only one fourth of the cases had to have surgery for relief of symptoms. Bilaterality is not uncommon; it was observed in one fourth of the patients, all of whom had mild disease.     

Hemifacial spasm in childhood

A nine-year-old girl presented with right hemifacial spasm (HFS) of 27 months duration. Stimulation of the right supraorbital nerve produced synkinesis of the ipsilateral facial muscles. Latency and amplitude of the blink reflex were equal bilaterally. Other investigations including computerized tomography (CT) were negative. Treatment with carbamazepine was not helpful. This is the third reported case of HFS in childhood.     

Hemifacial spasm in sleep

We conducted polygraphic studies during wakefulness and all-night sleep in 13 patients with cryptogenic and 3 with postparalytic hemifacial spasm. The movements decreased progressively with deepening sleep stages, reaching lowest values in REM sleep. The reduction was inversely related to the severity of movements during wakefulness. There was no relation between hemifacial spasm and mimic activity on the unaffected side. Central inhibitory processes may account for the partial decline in intensity of the movements in sleep.     

Psychologic and social adjustment to epilepsy in Rochester, Minnesota

The psychologic and social aspects of epilepsy have rarely been assessed in community-based samples. We administered the Washington Psychosocial Seizure Inventory in 1985-1986 to 125 nonretarded adults, 18 to 59 years of age, who in 1980 had active epilepsy and resided in Rochester, Minnesota. Individuals having seizures or taking anticonvulsant medications within the past 12 months had somewhat poorer adjustment than those without recent seizures or medications, but even this more severely affected group appeared relatively well adjusted.