Prevalence of Alzheimer's disease and dementia in two communities: Nigerian Africans and African Americans.

OBJECTIVE: This article reports on a prevalence study of dementia and Alzheimer's disease among two groups of subjects with the same ethnic background but widely differing environments. METHOD: The study was conducted among residents aged 65 years and older in two communities: Yorubas (N = 2,494) living in Ibadan, Nigeria, and African Americans (N = 2,212 in the community and N = 106 in nursing homes) living in Indianapolis, Indiana. The study design consisted of a screening stage followed by a clinical assessment stage for selected subjects on the basis of their performance on the screening tests. RESULTS: The age-adjusted prevalence rates of dementia (2.29%) and Alzheimer's disease (1.41%) in the Ibadan sample were significantly lower than those in the Indianapolis sample, both in the community-dwelling subjects alone (4.82% and 3.69%, respectively) and in the combined nursing home and community samples (8.24% and 6.24%, respectively). The prevalence rates of dementia and Alzheimer's disease increased consistently with advancing age in both study groups. CONCLUSIONS: To the authors' knowledge, this is the first study, using the same research method at the two sites, to report significant differences in rates of dementia and Alzheimer's disease in two different communities with similar ethnic origins.

Hereditary neurodegenerative disorders in Nigerian Africans.

Of 2.1 million patients seen in 25 years at the University College Hospital, Ibadan, Nigeria, only 25 suffered from heredodegenerative disorders of the nervous system. Six patients had hereditary ataxia, 10 essential tremor, 4 Huntington's chorea, 2 ataxia telangiectasia, and 3 Charcot-Marie-Tooth disease.

Tropical spastic paraparesis in the Seychelles Islands: a clinical and case-control neuroepidemiologic study.

We confirmed the occurrence of endemic tropical spastic paraparesis (TSP) in the Seychelles. Most patients (14/21) were low-income black women. Mean age at onset was 42.8 years (range, 20 to 65). In 62%, onset and progression were slow. Complete paralysis developed in 8/21 (38%) after an evolution of 2 to 15 years. All patients had bilateral pyramidal signs. Loss of vibratory perception occurred in 6/21 (28%). A case-control study of putative risk factors failed to show significant differences. The clinical and epidemiologic features of TSP in the Seychelles appear to be similar to those described in other tropical countries.

Comparison of the prevalence of Parkinson's disease in black populations in the rural United States and in rural Nigeria: door-to-door community studies.

A door-to-door survey of Parkinson's disease (PD) in Copiah County, Mississippi, using a pretested screening procedure (with a high sensitivity for detecting PD), followed by examination of all positives by a senior neurologist, revealed similar prevalence ratios for blacks and whites. The same procedure was applied in the community of Igbo-Ora, Nigeria, a black population of West Africa. To assure uniformity in the procedures and application of the diagnostic criteria, a neurologist from each survey site visited the other site. Among a black population of 3,521 over age 39 in Copiah County, there were 12 cases of PD, with an age-adjusted prevalence ratio of 341/100,000. The comparable figures for Igbo-Ora were as follows: population over age 39 = 3,412; cases of PD = 2; age-adjusted prevalence ratio = 67/100,000.

Cryptococcal granuloma (toruloma) of the central nervous system in a patient with schistosomiasis.

A case of cryptococcal granuloma of the brain and lung is described in a Nigerian woman who also had Schistosoma haematobium infection.

A pilot study of dementia in Ibadan, Nigeria.

The initiation of collaborative research involving investigators in developing and developed nations is a complex task. Four key areas to consider in collaborative, international research studies are discussed: administrative concerns, resources, understanding the research design, and problem solving. An example of a successful, international collaborative study of dementia in Ibadan, Nigeria is presented. Factors contributing to the successful outcome are detailed. The importance of the four key areas in the effective implementation of a research project are illustrated.

Computed tomographic density changes in schizophrenic and manic Nigerian subjects.

There is paucity of computed tomography (CT) studies from developing countries, where schizophrenia is said to have more favourable outcome and present predominantly with positive symptoms. We highlight the densitometric analysis of frontal and parietal areas, assessed by tracing of regions of interest on the slice that passes through the foramen of Monro and the pineal gland. The relationships of the density values with clinical and CT measures were investigated. Fifty schizophrenics, 14 manic and 41 normal subjects were compared. The schizophrenics were assessed with Andreasen's scale for negative symptoms, and outcome was based on the social and clinical condition in the past year. There were no significant differences in mean ages and brain slice area across the groups. In analysis of variance, schizophrenics and manics had significantly higher frontal density than normals. Schizophrenics had significantly higher parietal density than manics and normals (p < 0.001). Parietal density was significantly higher than frontal density, for schizophrenics and normals (p < 0.001). For the patients, density values were not significantly correlated with linear CT measures of atrophy (e.g. ventricle: brain area ratio) and duration of illness. Density values were not significantly associated with outcome, presence of negative symptoms, and visual ratings of cortical sulci and central atrophy. Our findings indicate that schizophrenia in developing countries is also associated with non-specific brain abnormalities.

Do young schizophrenics with recent onset of illness show evidence of hypofrontality?

Young schizophrenic patients (n=43), manic controls (n=32), both groups diagnosed according to the Research Diagnostic Criteria and on remission from acute illness, and 53 normal subjects were given a battery of neuropsychologic tests selected to assess different functional areas in the brain. Compared with normal controls, patient groups showed evidence of impaired functioning of many cortical areas but with the schizophrenics having the worst performance. In addition, schizophrenic patients performed poorly in tests designed to assess frontotemporal cortical functioning. This pattern of deficits differentiated schizophrenics from both manic and normal subjects. The results suggest that widespread cognitive deficits are a feature of both schizophrenia and mania but that frontal lobe dysfunction may be more specific to the former. It would also appear that these impairments are not artefacts of age, chronicity or of institutionalization, and are present even in schizophrenic patients who may have an illness with putative better outcome than those studied in previous reports.

Cross-cultural studies in Alzheimer's disease.

The search for risk factors for Alzheimer's disease would be greatly enhanced by identification of populations with significantly different prevalence rates, particularly if these populations consisted of ethnic groups now living in different environments and cultures. Evidence is presented that two such groups are worthy of further study: subjects of African origin living in Africa and in the West and Native Americans living on and off reserves.

Obstetric neuropraxia in the Nigerian African.

The results of a prospective study of 34 Nigerian women with obstetric neuropraxia (puerperal paresis of the lower limbs) seen at the University College Hospital, Ibadan, are presented. The height of 29 (84%) was under 62 in (1.58 m). All were younger than 45, and 41% (14) were primiparous. Lumbosacral plexus injury with a foot-drop was the most frequent presenting feature (88%), bilateral involvement was observed in 13 patients (38%), femoral neuropathy was observed in nine (26%) and the ankle tendon jerks were absent in 35%. Spastic paraparesis was not uncommon (15%). Results of electromyographic examination and determinations of conduction velocities were consistent with proximal neuropraxia of the lumbasacral trunk in many of them (88%). The presentation of the fetus was cephalic in 97% of the women. The major predisposing factor was prolonged labor. Among the complications associated with the neuropraxia were hydroureters above the pelvic brim and vesico- and rectovaginal fistulae. Perinatal mortality was high particularly with labor of more than 18 hours. Recovery from the neuropraxia was complete for 76% of the patients. It is concluded that direct pressure on the lumbosacral plexus and nerve trunks by the presenting fetal part is the major factor in the pathogenesis of obstetric neuropraxia encountered in Nigerians.

Profile of dementia in a Nigerian community--types, pattern of impairment, and severity rating.

Out of 2494 subjects screened in a Nigerian community, 28 patients with dementia were identified. Alzheimer's disease was diagnosed in 18 patients (64.3%), 16 of whom had probable Alzheimer's disease. Eight patients (28.6%) had vascular dementia while one patient each had parkinsonism with dementia and depression with dementia. Patients with Alzheimer's disease were significantly older, predominantly females and illiterates. Cognitive deficit commonly took the form of memory and judgment impairment while financial mismanagement was the most frequent impaired activity of daily living. More than half of the cases had mild disease on severity rating and were comprised mainly of Alzheimer's disease subjects. These results confirm the higher frequency of Alzheimer's disease over the other types as reported in other communities.

Effectiveness of anticonvulsant therapy in the epilepsies in Nigerian Africans.

We evaluated the effectiveness of anticonvulsant drugs in 175 Nigerians of whom 106 were males, who suffer from epilepsy. The mean age at onset of seizures was 17.5 years and over 60% had seizures for more than one year before the commencement of therapy. Partial seizures were encountered in 98 (56%) subjects, and generalised seizures in 44%. One hundred and twenty six subjects were on single drug therapy and phenobarbital was the single most commonly prescribed agent. There was complete seizure control in 30 (17%), more than 50% control in another 87 (50%), and poor control in 58 (33%) of them. The factors associated with good control were infrequent seizures and monotherapy. The duration of seizure, and absence of aetiologic factor were not correlated with good control. There was no significant difference between phenobarbital and phenytoin effectiveness in seizure control. Adverse drug effects--mainly drowsiness and movement disorders--were encountered in 61 subjects. We conclude that the currently administered anticonvulsants are effective in 67% of the Nigerian patients studied and phenobarbital should remain a major drug because of economic considerations, availability and low side effects profile.

Factors associated with epileptiform EEG patterns in Nigerian epileptics.

We reviewed electroencephalographic (EEG) records of 626 epileptic patients for the frequency of epileptiform patterns (EP). The purpose of this study was to determine the factors determining the occurrence of EP. Epileptiform pattern was detected in 46% of patients studied. The occurrence of EP was associated with age, seizure type, longer duration of epilepsy, and proximity of EEG examination to last attack. We found no association between seizure frequency, medication status at EEG examination and the occurrence of EP. The yield of diagnostically useful findings in the interictal EEG would be increased if the test is performed as close as possible to the last seizure.

Xenobiotic metabolism in idiopathic Parkinson's disease in Nigerian Africans.

The acetylator phenotype using sulphadimidine as a probe drug was studied in 20 idiopathic Parkinson's disease (IPD) patients and 21 control subjects. 10(50%) of the IPD patients belonged to the slow acetylator phenotype but this did not differ significantly from the proportion 7 (33%) of control subjects who were slow acetylators. The result does not suggest a role for acetylation in the aetiopathogenesis of IPD in Nigerian African.

Two-year remission in Nigerian epileptics.

Seizure profile of 208 male and 137 female Nigerian epileptic patients was studied. The mean age at onset was 21 years and partial seizures predominated at 53.3%. One hundred and forty eight out of the 255 patients (58%) followed up for more than two years attended clinics regularly and 107 defaulted. Only 88 patients (25.5%) were compliant with therapy. Factors associated with two-year seizure remission were: drug compliance (OR = 4.4; 95% CI: 2.0, 9.5) and less than six attacks before therapy commencement (OR = 2.3; 95% CI: 1.1, 4.7). The study revealed high clinic default rate and low therapy compliance as major problems in management of epileptic patients. Health education to improve these and early institution of therapy appear necessary to reduce the proportion of patients that could become chronic epileptics.

Screening for dementia in elderly Nigerians: results of the pilot test of a new instrument.

We developed a new instrument for the assessment of cognitive functions in elderly Nigerians as a preliminary step towards the determination of the burden of dementia in Nigerian Communities. The instrument was pilot tested on 250 cognitively-normal Nigerians and their scores compared with those of 15 subjects with clinically-diagnosed dementia. The cognitively normal subjects had a mean score of 24 (SD 2.3) while the cognitively-impaired subjects had a mean of 35 (SD 3.0) and p less than 0.01). Of those with normal cognition, subjects with at least 6 years of education had significantly lower mean scores than illiterates (p less than 0.005). The instrument was completed in 4 minutes in normal subjects as against 7 minutes in those with cognitive impairment. The 19 item instrument had a sensitivity of 80% and a specificity of 72% at a cut-off value of 27. With the elimination of 3 items related to information, the sensitivity and specificity increased to 93% and 83% respectively. We conclude that the 16 item version is adequate for a 2 stage study of dementia in this environment, its main role being that of screening in the first stage.

Rarity of dementia (by DSM-III-R) in an urban community in Nigeria.

Dementia of the elderly, a public health problem world-wide, is underdocumented in black Africa. We carried out a door-to-door survey in Idikan in NW3 ward, a political and administrative unit, with a population of 9000: in Ibadan city, Nigeria, to determine the burden of dementia. Census and demographic listing was done by trained clinical students who concurrently administered a modified Mini Mental State Examination as a screening instrument to those aged 40 years or more. Only 2 out of 932 subjects refused: 293 (31%) were aged 65 years or more. Those who were positive to the screening test and 20% of negatives were investigated by neurologists. Decline in cognitive function significantly correlated with age, female sex and low level of education. Impaired cognition was present in 41 (4.4%) but was due to depressive disorders in 7 (0.6%) patients. In none of the remaining 34 (3.8%) subjects could a diagnosis of dementia as defined by DSM-III-R be justified.

Prevalence of headache and migrainous headache in Nigerian Africans: a community-based study.

In a door-to-door survey in a Nigerian town with stable population of about twenty thousand, 18,594 subjects were screened with a questionnaire, which involved a complete census, administered by non-doctor, including primary health care personnel. Migrainous headache was diagnosed on the basis of combination of responses to the questionnaire shown in a pilot study validated by neurological examination to have 92% sensitivity and 99% specificity. Crude life time prevalence ratio of at least one episode of headache unspecified was 51 percent (50% in males and 52% in females). The crude prevalence ratio of migrainous headache was 5.3 per 100 (5 per 100 in males and 5.6 per 100 in females), with peak age-specific prevalence ratios in the first decade in both males and females. Migrainous headache was three times as common in females as in males in the second and third decades. Prevalence of migrainous headache in Nigerian Africans appears less than in Caucasians. No social status was at special risk to developing migrainous headache.

The distinctive value of temperature pattern in liver cirrhosis and abdominal tuberculosis.

We assessed the temperature pattern in liver cirrhosis and abdominal tuberculosis during the first week of admission, before institution of definitive therapy. In 22 patients with liver cirrhosis, 59.19pc had subnormal temperatures and 9.1pc were pyretic. In 19 patients with abdominal tuberculosis, 31.6pc had subnormal temperatures and 36.8pc were pyretic (P less than 0.05). The group mean temperature of the cirrhotic patients lies within the subnormal temperature range while that of patients with abdominal tuberculosis lies within the normal range. This study suggests that patients with liver cirrhosis tend to develop subnormal temperatures much more than those with abdominal tuberculosis while pyrexia was commoner in the latter. The pattern of a carefully recorded and charted temperature can thus be of added distinctive value in situations where liver cirrhosis and abdominal tuberculosis pose diagnostic problems, where definitive diagnosis cannot be readily made or is delayed as a result of inadequate facilities.

Determination of ages of elderly Nigerians through historical events: validation of Ajayi-Igun 1963 listing.

We compared ages of 59 elderly Nigerians subjects determined independently by records and historical events to validate the Ajayi-Igun listing of 1963. There was no statistically difference between the mean ages of the subjects as determined by the 2 methods (p > 0.05). In almost 50% of the subjects, the ages were exactly the same by both methods and in 93.2%, the difference in ages was 3 years. There was a high significant correlation between the two methods of age determination (Spearman correlation coefficient rs = 0.989, p < 10(-5)). Our study validate the use of historical listing for accurate age determination in Nigerians and its use is advocated for epidemiologic studies and other demographic needs in circumstances where written records of births are lacking.