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July2010 Vol.47 Issue:      3 (Supp.) Table of Contents
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Epidemiology of Cerebellar Ataxia in Al-Kharga District-New Valley (Egypt)

Wafaa M. Farghaly1, Hamdy N. El-Tallawy1, Tarek A. Rageh1,  Ghaydaa A. Shehata1, Nabil A. Metwally2, Noha M. Abo-Elfetoh1

 

Departments of Neurology, Assiut University1; El-Azhar University, Assiut Branch2; Egypt

 



ABSTRACT

Background: Rare comprehensive epidemiological studies of ataxia have been undertaken worldwide. Objective:  To estimate the prevalence of cerebellar ataxia and its subtypes in Al-Kharga District - New Valley. Methods: This is a community based study carried out through three stages. Total populations 62,583 were screened door to door (every door) by three specialists of neurology. All suspected patients were subjected to complete medical, neurological examination and brain MRI.           Results: Twenty four patients of Cerebellar ataxia were recorded in this study with prevalence rate PR 38.34/100,000(95%CI; 23.01-53.69). The order of frequency of different types of cerebellar ataxia was as follows; 8 patients had vascular cerebellar ataxia (PR: 12.8/100000; 95%CI: 3.93 - 21.64), 6 patients had ataxic cerebral palsy (PR: 9.6/100,000; 95%CI: 1.92 - 17.26), 5 patients had unclassified progressive cerebellar ataxia (PR: 8/100,000; 95%CI: 0.99-14.99), 3 patients had post encephalitic ataxia  (PR: 4.8/100000; 95%CI: 0.63 - 10.22) and 2 patients had Early onset hereditary Friedreich-like ataxia (PR: 3.2/100,000; 95%CI: 1.23 - 7.62). Conclusion: The prevalence rate of cerebellar ataxia in Al-Kharga District-New Valley (Egypt) is 38.34/100,000. [Egypt J Neurol Psychiat Neurosurg.  2010; 47(3): 527-532]

 

Key Words: cerebellar ataxia, prevalence, subtypes, Egypt.

 

Correspondence to Tarek A. Rageh. Department of neurology and psychiatry, Assiut University hospitals, Egypt.

Fax: +02 (088) 2333327. E-mail: tarek-rageh@hotmail.com.





INTRODUCTION

 

The term cerebellar ataxia is applied to indicate ataxia due to dysfunction of the cerebellum1. Ataxia describes a lack of coordination while performing voluntary movements, it may appear as clumsiness, inaccuracy, or instability, movements are not smooth and may appear disjointed or jerky2. How and where these abnormalities manifest depend on which cerebellar structures are affected, and whether the lesion is bilateral or unilateral1.

There are many diseases that may lead to ataxia, determining the cause of ataxia may be very difficult and requires a careful series of steps planned by an experienced physician3. Often, the diagnosis cannot be made immediately, but must await careful examination of the progression or resolution of symptoms over time4. In some cases (vascular, demyelinating, inflammatory and neoplasm), it is important to make the diagnosis rapidly so that treatment may be started before further damage occurs4.

Approximately 150,000 people in the United States alone are affected by ataxia, either the acquired or hereditary form with lifetime prevalence rate is about 50/100,000.1 Previously reported estimates from isolated and selected populations have yielded prevalence for hereditary ataxias between 0.31 and 41 per 100 000.5 Friedreich's ataxia is the most common inherited ataxia, occurring in 1 out of 50,000 populations1. In a study in the Trottori, Japan, a Spinocerebellar Ataxia (SCA) prevalence of 17.8 per 100.000 was found, in that study6, Spinocerebellar Ataxia type 6 (SCA6) was the most prevalent, accounting for about one-quarter of the identified families, and for 11% of the sporadic cases7.

The aim of this study is to determine the prevalence of cerebellar ataxia and its different subtypes in Al-Kharga district (Egypt).

 

PATIENTS AND METHODS

 

This was a community-based study carried out in Al-Kharga District-New Valley. The New Valley represents about 44 % of Egypt area. It is divided into Al-Kharga, Al-Farafra, and Al-Dakhla Districts. The team work chose this area because it is different from Nile valley countries, due to different geography, social, economic, cultural characteristics and high rate of genetic diseases as it considered as closed areas which make it a homogeneous entity. In addition, it is a poor area and far away from the medical services (as there is no neurologists, no educational hospitals for advanced health facilities concerning this specialty).

Informed written consent was obtained from all subjects included in this study or from responsible person in each family and Health Institute. Regional Ethical committee of Assiut University Hospital had approved this study.

Total population was 62,583. The distribution of sample was 44,600 (71, 3%) subjects from urban and 17,983 (28.7%) from the rural area. The study sample was investigated by multistage sampling procedure. The first stage was carried out by screening all population through door to door (every door) by three specialists of neurology in Al Kharga District - New Valley Governorate (Egypt). A reliable and valid short term Arabic screening scale was prepared specifically for detection any case with neurological impairment and it was suitable for our population8. Then, the suspected cases were referred to Assiut university hospital in which meticulous systemic and neurological evaluation were carried out by six specialists of neurology separately. Each patient was subjected to MRI, metabolic screening according to need, EEG, ----etc to confirm diagnosis.

Cerebellar ataxias were defined and classified according to clinical, mode of onset, etiology and inheritance9.

Diagnosis of cerebellar ataxia is based on a person's medical history, family history, and a complete neurological evaluation including MRI scan on the brain. All cases had cerebellar ataxia were included in this study. Ataxia due to another causes rather than cerebellar as sensory ataxia were excluded from this study. In epidemiology, the term 'prevalence' of Cerebellar ataxia usually refers to the estimated population of people who are managing Cerebellar ataxia at any given time10. Cerebellar ataxias are rare and prevalence rate of various disorders were in 100,000.

In this study, the population and patients were classified into age groups according to Nichols11 into childhood 0-<18, adulthood 18-< 40, middle age 40-<60 and elderly 60 and more.

Vascular cerebellar ataxia was diagnosed on basis of presence of history suggest of vascular origin as infarction or hemorrhage12. Ataxic Cerebral Palsy was diagnosed according to Stanely13. Postencephalitic ataxia was diagnosed   on basis of history of encephalitis confirmed by medical report from doctor or hospital prior to the onset of cerebellar ataxia with EEG record. MRI brain and/or serological findings. Unclassified progressive ataxia (? Metabolic) was diagnosed according to Fletcher9, Klemm and Conzelmann14 and Chinnery and Turnbull15. Early onset hereditary Friedreich-like ataxia was diagnosed based on clinical data16.

 

Statistical Methods

The statistical package for social sciences (SPSS) for Windows version 12.0.1 (SPSS Inc., Chicago, IL) and Epicalc 2000 were used for data analysis. The Chi Square Test, Independent –Samples T test or One Way ANOVA test followed by Post Hoc test(LSD) were used to analyze differences in proportions between groups. The 95% Confidence interval for the prevalence was calculated through Excel Program. Odds Ratio and 95% Confidence interval were used to compare sex (male and female) and residence (urban and rural) by chi square. The significant level of 0.05 was chosen.

 

RESULTS

 

Demographic data, duration of illness, radiological data of 24 patients with cerebellar ataxia are illustrated in table (1).

Table (2) illustrated that twenty four patients had cerebellar ataxia, with prevalence rate 38.34/100,000(95% CI: 23.01-53.69). Those patients were classified into: Seventeen patients with cerebellar ataxia (70.8%) had Acquired ataxia (Non-inherited cerebellar ataxias) with lifetime prevalence was 27.16/100,000(95% CI: 14.3- 40.1) and seven patients (29.2%) had Inherited cerebellar ataxias with lifetime prevalence was 11.19/100,000(95% CI: 2.90-19.47). The order of frequency of different types of cerebellar ataxia was as follows; 8 patients had vascular cerebellar ataxia (PR: 12.8/100000; 95%CI: 3.93 - 21.64), 6 patients had ataxic cerebral palsy (PR: 9.6/100,000; 95%CI: 1.92 - 17.26), 5 patients had unclassified progressive cerebellar ataxia (PR: 8/100,000; 95%CI: 0.99-14.99), 3 patients had post encephalitic ataxia  (PR: 4.8/100000; 95%CI: 0.63 - 10.22) and 2 patients had Early onset hereditary Friedreich-like ataxia (PR: 3.2/100,000; 95%CI: 1.23 - 7.62). There were non-statistically significant difference in the prevalence rate between male and female (Table 3). Table (4) showed the order of age specific prevalence of different types of cerebellar ataxia at different age groups.


 

Table 1. Demographic, Clinical and radiological criteria of patients with ataxia in El-Kharga district, Egypt

 

Variables

Patients data

Age (mean±SD)

29.26±23.19 (rang 5-70)

Sex (n & %)

     Males

     Females

 

13                (54.2%)

11               (45.8%)

Residence (number & percentage)

     Rural

     Urban

 

9 (36.0%)

16 (64.0%)

Level of education (number & percentage):

preschool

Illiterate

Read and write

Primary school

Preparatory school

Secondary school

University

 

4 (16.7%)

15(62.5%)

0

2 (8.3%)

3 (12.5%)

0

1 (4.2%)

Duration of illness /month (mean ±SD)

33.84 ± 56.07 (0.00-264.0)

MRI finding (no. & %)

·                  Normal

·                  Infarction

·                  Hemorrhage

·                  Atrophic changes

 

12(50%)

6(25%)

1(4.2%)

5(20.8%)

MRI  magnetic resonance imaging, SD standard deviation

 

 

Table 2. Classification and lifetime prevalence rate of cerebellar ataxia and its different types in El-Kharga district, Egypt.

 

 

Number (prevalence rate/100,000

95%Confidince Interval

Acquired ataxia(Non-inherited cerebellar ataxias):

·                  Vascular ataxia

·                  Postencephalitic ataxia

·                  Ataxic Cerebral Palsy

17(27.16)

8 (12.78)

3 (4.79)

6 (9.59)

14.3- 40.1

3.93 - 21.64

0.63 - 10.22

1.92 - 17.26

Inherited cerebellar ataxias:

·                  Early onset hereditary Friedreich-like ataxia

·                  Progressive metabolic ataxia

7 (11.19)

2  (3.20)

5  (7.99)

2.90-19.47

1.23 - 7.62

0.99-14.99

Total cerebellar ataxia

24 (38.35)

23.01-53.69

Values were given as number (prevalence rate /100,000)

Monte Carlo confidence level 95% was used

 

 

Table 3. Prevalence rate of cerebellar ataxia and its subtypes, according to sex and residence distribution community in El-Kharga district, Egypt.

 

 

 

Male

(n =32165)

Females

(n =30418)

P value

Urban

(n = 44600)

Rural

(n = 17983)

P value

Acquired ataxia (Non-inherited cerebellar ataxias)

·                  Vascular ataxia

·                  Postencephaltic ataxia

·                  Ataxic Cerebral Palsy

10(31.1)

4 (12.44)

2 (6.22)

4 (12.44)

7 (23.01)

4 (13.15)

1 (3.29)

2 (6.58)

0.356

0.606

0.521

0.371

12(26.91)

6 (13.45)

2 (4.48)

4 (8.97)

5 (27.80)

2 (11.12)

1 (5.56)

2(11.13)

0.418

0.584

0.632

0.552

Inherited cerebellar ataxias

·                  Early onset hereditary Friedreich-like ataxia

·                  Progressive  metabolic ataxia

3(9.3)

2 (6.22)

1 (3.11)

4(13.2)

0

4 (13.15)

0.471

-

0.171

3(6.73)

2 (4.48)

1 (2.24)

4 (22.24)

0

4 (22.24)*

0.107

-

0.026

Total  cerebellar ataxia

13(40.42)

12(39.45)

0.473

15 (33.63)

9 (50.05)

0.230

P value < 0.05 at Exact Sig. (1-sided); Values were given as number (Prevalence rate /100,000)

Table 4. Prevalence rate cerebellar ataxia and its subtypes per 100,000, according to age groups distribution.

 

 

 

Childhood

n=25,539

Early

adulthood

n=23,070

Late

adulthood

n=10,758

Elderly

n=3,216

P value

Acquired ataxia (Non-inherited cerebellar ataxias):

* Vascular ataxia

* Postencephaltic ataxia

* Ataxic Cerebral Palsy

7(27.41)

0

1 (3.92)

6 (23.50)

3(13.0)

1 (4.33)

2 (8.67)

0

3(27.89)

3 (27.9)

0

0

4(124.38)

4(124.38)

0

0

0.082

0.000*

0.692

0.015*

Inherited cerebellar ataxias:

*Early onset hereditary Friedreich-like ataxia

* Progressive ataxia

4(15.66)

1(3.92)

3 (11.75)

2(8.67)

0

2 (8.67)

1(9.3)

1(9.30)

0

0

0

0

0.326

0.829

0.233

Total cerebellar ataxia

11 (43.07)

5(21.68)

5(46.50)

4(124.38)

0.223

We compare different age groups by proportions as trend using Epicalc2000, rate /100,000)

 


DISCUSSION

 

This is a community based study aimed to determine the prevalence rate of cerebellar ataxia among all population who lived in Al-Kharga District. The prevalence rate of cerebellar ataxia varies considerably between studies and countries. The lifetime prevalence of cerebellar ataxia in our study is 38.34 /100,000. This prevalence is nearly similar to the prevalence of cerebellar ataxia in USA which is 50/100,000.1 However, this prevalence rate is higher than other results as in Libya17, in which the prevalence was 2.7/100,000 and in Italy18, it was 9/100,000. These prevalence rates were underestimated as the authors specify their work only upon spinocerebellar ataxia while other studies due to acquired ataxias as well as hereditary ataxias19 not involved in their studies. The prevalence of Acquired ataxia (Non-inherited cerebellar ataxias) in this study is 27.16 /100,000 (95%CI; 14.3- 40.1), which is higher than study carried out in south east Wales, UK in 2004 (prevalence rate 8.4 per 100,000 (95% CI 7.2 to 11.6)20. This difference returned to, in they recorded only late onset acquired ataxia > 18 years.

The prevalence rate of inherited cerebellar ataxia in our study is 11.2/100,000 (95% CI: 2.90-9.47).This is matched with previous study in Italy at 2004, yielding prevalence rate 9/100,000(95% CI: 5-24)18. However, our results are higher than previous study which was carried out in Norwegian with prevalence rate 6/100,000 (95% CI: 2-19)19 and 1.8 per 100 000 ((95% CI: 0.8 to 2.7) in South East Wales, UK (late onset acquired ataxia > 18 years18.

The lifetime prevalence rate of early onset hereditary Friedreich-like ataxia in this study is 3.2/100,000 that is matched with the range of 2-4.7/100,000 lifetime prevalence rate in previous studies17,21,22. As regard other types like as vascular, Postencephalitic and unclassified progressive ataxia (? Progressive metabolic ataxia), there is a paucity of data and the lack of health records about these types.

There is no significant difference between male and females in Friedreich’s ataxia21.Our results were matched with that as regard lifetime prevalence for ataxia and its subtypes. However, the lifetime prevalence rate of unclassified progressive ataxia (? Progressive metabolic as Leukodystrophy and MERF mitochondrial disease) was significant higher in rural community more than urban community. This can be explained as Al Kharga District is closed area, in which it has high prevalence of genetic diseases. In addition, the consanguinous marriage is highly in the rural area than urban community.

In childhood, the age specific prevalence rate was higher frequency of inherited and genetic type followed by Postencephalitic type. This matched with other previous studies, which reported that, the early age of onset and affection of inherited ataxic type as Friedreich's, and unclassified progressive type7,9,14,21. In early adulthood, all types were recoded except CP type. The same was noticed in middle age group in addition to disappearance of unclassified progressive type. 

In elderly group, the only recorded type was vascular type. That could be explained by the increase prevalence rate of stroke at this age group as the chance of having a stroke approximately doubles for each decade of life after age 55 years12. On the other hand, the speed at which the ataxia progresses varies between different types of ataxias and between individuals, but it is very slow, and changes take place over many years23. The age at which symptoms begin also varies between the types of cerebellar ataxias. Some tend to start in childhood, others later on in life23.

 

Conclusion

The prevalence rate of cerebellar ataxia Al-Kharga District (Egypt) is 38.4/100,000 (95%CI; 23.01-53.69). The order of frequency of different types of cerebellar ataxia was as follows; Acquired (none inherited) cerebellar ataxia is 27.2/100,000 and followed by Inherited cerebellar ataxia is 11.2/100,000.

 

[Disclosure: Authors report no conflict of interest]

 

REFERENCES

 

1.        Schmahmann JD. Disorders of the Cerebellum: Ataxia, Dysmetria of Thought, and the Cerebellar Cognitive Affective Syndrome. J Neuropsychiat Clin Neurosci. 2004; 16:367–78.

2.        Storey E, Gardner RJ, Knight MA, Kennerson ML, Tuck RR, Forrest SM, et al. A new autosomal dominant pure cerebellar ataxia. Neurology. 2001; 57(10):1913-5.

3.        Miyoshi Y, Yamada T, Tanimura M, Taniwaki T, Arakawa K, Ohyagi Y et al. A novel autosomal dominant spinocerebellar ataxia (SCA16) linked to chromosome 8q22.1-24.1. Neurology.  2001; 57(1):96-100.

4.        Koide R, Kobayashi S, Shimohata T, Ikeuchi T, Maruyama M, Saito M, et al. A neurological disease caused by an expanded CAG trinucleotide repeat in the TATA-binding protein gene: a new polyglutamine disease? Hum Mol Genet. 1999; 8(11):2047-53.

5.        Muzaimi MB,  Thomas J,  Palmer-Smith S, Rosser L, Harper PS, Wiles CM,  et al. Population based study of late onset cerebellar ataxia in South East Wales. J Neurol Neurosurg Psychiatry. 2004; 75:1129–34.

6.        Nakamura K, Jeong SY, Uchihara T, Anno M , Nagashima K, Nagashima T, et al. SCA17, a novel autosomal dominant cerebellar ataxia caused by an expanded polyglutamine in TATA-binding protein. Hum Mol Genet. 2001; 10(14):1441-8.

7.        Fujigasaki H, Martin JJ, De Deyn PP, Camuzat A, Deffond D, Stevanin G, et al. CAG repeat expansion in the TATA box-binding protein gene causes autosomal dominant cerebellar ataxia. Brain. 2001; 124(Pt 10):1939-47.

8.        El-Tallawy HN, Farghaly WM, Metwally NA, Shehata GA, Rageh TA, Abo-Elfetoh NA. Epidemiology of Non-Fatal Cerebrovascular Stroke (CVS) in Al-Kharga District-New Valley (Egypt), 1st Egyptian International Neuroepidemiology Conference. Neuroepidemiology.  2009; 32:242–50.[Abstract]

9.        Fletcher N. Tremor, ataxia, and cerebellar disorders. In: Donaghy M, Brain WRB, editors.  Brain's diseases of the nervous system. Oxford: Oxford University Press: 2002. p.980-94.

10.     Ross JB, Finklestein S, Arana GW. The predictive power of diagnostic tests and the effect of prevalence of illness. Arch Gen Psychiatry. 1983; 40 (5): 569–73.

11.      Nichols TA, Rogers WA, Fisk AD, West LD. How old are you? For age classifications as reported in human factors, Proc Human Factors Ergo. 2001; 260- 1.

12.      Min WK, Kim YS, Kim JY, Park SP, Suh CK. Atherothrombotic Cerebellar Infarction : Vascular Lesion-MRI Correlation of 31 cases. Stroke. 1999: 30; 2376-81.

13.     Stanley F, Blair E, Alberman E. Cerebral Palsies: Epidemiology and Causal Pathways. London: MacKeith Press; 2000.

14.      Klemm E, Conzelmann E. Adult onset metachromatic leukodystrophy presenting without psychiatric symptoms. J Neurol.1989; 9:427-9.

15.     Chinnery P, Turnbull D. Clinical features, investigation and management of patients with defects of mitochondrial DNA. J Neurol Neurosurg Psychiatry. 1997; 3: 559-63.

16.     Koht J, Tallaksen CM. Cerebellar ataxia in the eastern and southern parts of Norway. Acta Neurol Scand Suppl. 2007; 187:76-9.

17.     Sridharan R, Radhakrishnan K, Ashok PP, Mousa ME. Prevalence and pattern of Spinocerebellar degeneration s` in northeast stern Libya. Brain. 1985; 108:831-43.

18.     Zortea M, Armani M, Pastorello E, Nunez GF, Lombardi S, Tonello S, et al. Prevalence of inherited ataxias in the province of Padua, Italy. Neuroepidemiology. 2004; 23:275-80.

19.     Klockgether T. Ataxias. Diagnostic procedure and treatment, Nervenarzt. 2005 Oct; 76(10):1275-83; quiz 1284-5.[Abstract]

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21.     Friedreich's ataxia. [Internet]. Wikipedia, the free encyclopedia; 2008. [Updated 2008 Feb]. Available from: http://en.wikipedia.org/wiki/Friedreich_ataxia.

22.     Polo JM, Calleja J, Combarros O, Berciano J. Hereditary ataxias and paraplegias in Cantabria, Spain an epidemiological and clinical study. Brain. 1991: 114; 855-66.

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الملخص العربى

 

وبائيات مرض الرنح فى إقليم الخارجة بالوادى الجديد- مصر

 

قد تمت هذه الدراسة من خلال مسح ميدانى شامل لأبناء منطقة الخارجة بالوادى الجديد لدراسة نسبة حدوث مرض الرنح.

تمت دراسة اثنين وستون ألف وخمسمائة ثلاث وثمانون فردا حيث تم فحص هؤلاء الأفراد بواسطة ثلاثة أخصائيين أمراض عصبية من خلال المنازل( كل المنازل) وقد تم فحص الحالات المشتبه أصابتها بمرض الرنح بواسطة ثلاثة استشاريون للأمراض العصبية بمستشفى الخارجة العام ثم تم نقل هؤلاء المرضى لجامعة أسيوط حيث قام ثلاثة آخرون من استشاريون الأمراض العصبية بفحص هؤلاء المرضى كل على حدة وقد تم عمل أشعة بالرنين المغناطيسى على المخ لهؤلاء المرضى. 

أوضحت الدراسة: عدد المرضى المصابون أربعة وعشرين مريضا و أن نسبة الإصابة بهذا المرض تمثل  38.34/ 100,000 

وقد كانت أكثر نسبة من هذا المرض ممثلة فى صورة الرنح الناتج من الإصابة بالسكتة الدماغية ثم الشلل الدماغى الممثل فى صورة رنح  ثم الرنح الغير مصنف ثم الرنح الناتج من الالتهابات بالمخ ثم الرنح المسمى بـ  Friedreich's ataxia



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