Journal of Neurology & Neurophysiology

The Study of Electroencephalographic Changes in Patients Diagnosed with Dementia

Karthikeyan KV^*, Subramaniyan K and Shanu T ^*Correspondence: Karthikeyan KV, Department of Neurosurgery, Department of Neurology, Chettinad Academy of Research and Education, Chettinad Healthcity, Tamilnadu, India, Tel: 044-47428567, Email:

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Introduction

Dementia is a progressive deterioration of intellect, behavior and personality because of diffuse disease of cerebral hemispheres, maximally affecting the cerebral cortex and hippocampus. This disease can occur at any age but is most common in elderly. Incidence increases with increasing age. If it is occurs below the age of 65 years then it is labeled as presenile dementia.

Dementia Classification

Classification is based on causes

1. Degenerative-Pure dementia, Alzheimer’s disease Frontotemporal dementia

2. Dementia plus syndrome-Dementia with lewy bodies, Parkinson’s disease with dementia, Progressive supranuclear palsy, Hungtington’s disease

3. Cerebrovascular disease-Multiple infarct dementia, Subcortical ischemic vascular dementia

4. Structural disorders-Normal pressure hydrocephalus

5. Infectious-Creutzfeltd jakob disease, HIV,Syphilis

6. Nutritional-Thiamine and Vit B12def

7. Metabolic-Liver disease, Thyroid disease

8. Trauma-Head injury

9. Neoplasia or paraneoplasia-Frontal tumour

Symptoms

Classified based on site of involvement:

Frontal premotor cortex-Behavioural changes, Irresposible, Antisocial behavior, Antisocial behavior;Parietotemporal region- Disturbances of memory and language. Subcortical-Apathetic, Poor knowledge;Cortical- Dysphasia, Agnosia, Apraxia.

Criteria for Dementia

Diagnostic and statistical manual of mental disorders [DSM-5] criteria classifies dementia as a major cognitive disorder.

Criteria

One or more significant impairments in cognitive behaviors such as, Memory, Language, Execution of purposeful movement, Recognition, Familiarity, Selfcontrol management, Mathematics, Emotional expression\comprehension and Writing.

Initial Patient Assessment

The patient assessment should begin with detailed clinical history with focus on cognitive and behavioural symptoms. Detailed description of behavioural changes should be obtained from patient attenders especially close relatives such as spouses, parents, children etc.

Examinations

During examination look for focal signs, abnormal movements,pseudo-bulbar signs , Primitive reflexes like prout reflex, grasp reflex, glabellar tap reflex, palmomental reflex.

Mini mental status examination [MMSE]

1. 25-30: No cognitive impairment

2. 18-24: Mild cognitive impairment

3. 0-17: Severe cognitive impairment.

EEG in Demetia

An increase in EEG slow wave activity (theta and delta frequencies) together with decreased activity in the alpha frequency band are considered to be typical findings in the various types of dementia. Study of 38 patients with a diagnosis of AD at various stages of dementia EEG recordings were evaluated and found A decrease in alpha coherence and an increase in delta coherence were found to be most significantly correlated with the degree of dementia, assessed using the Mini-Mental State Examination score. EEG can be a useful tool in differentiating dementia from pseudodementia on the one hand [1-4].

Role of EEG as Biomarker in the Early Detection and Classification of Dementia. EEG as a useful clinical evaluation tool in the discrimination of AD and/or VaD and/or other types of dementia [5,6].

EEG comparisons in early Alzheimer’s disease, dementia with Lewy bodies and Parkinson’s disease with dementia patients with a 2-year followup Laura Bonanni,1 Astrid Thomas,1PietroTiraboschi, Bernardo Perfetti, SaraVaranese1and Marco Onofrj.

The authors in above study to evaluate whether EEG abnormalities can discriminate between DLB, AD and PDD in the earliest stages of dementia and to do this 50 DLB, 50 AD and 40 PDD patients and they found Our first relevant finding was the identification of slow activities (5.6–7.9 Hz) in posterior derivations of all DLB patients, which significantly differentiated these patients from those with AD.

EEG findings in dementia with Lewy bodies and Alzheimer’s diseaseR C G Briel, I G McKeith, W A Barker, Y Hewitt, R H Perry, P G Ince, A F Fairbairn-Seventeen of the total of 19 records from the patients with DLB were abnormal. Thirteen showed loss of alpha activity as the dominant rhythm and half had slow wave transient activity in the temporal lobe areas.

Materials and Methods

This study is an observational cross section study to analyse the EEG changes in dementia patients in a tertiary care hospital. A total of 30 patients were included in this study. All the patients diagnosed with Dementia/ Major Neurocognitive Disorder (DSM-5) attending the OPD were included. Patient below the age of 18 and patients who were found to have technical difficulty in carrying out EEG were excluded from this study.

Descriptive statistics were applied to calculate demographic variables like Mean, Median, Standard Deviation, Confidence Interval. Pie chart /Bar graph will be used to explain the EEG changes in demented individuals.

Results and Discussions

In this study surprisingly 70 Percent of the patients were females in contrast to many other studies in literature.

In this study maximum number of age group is 65-75(30%), in accordance with other studies. Younger the age lesser the incidence. This study showed more than 70 percent of the patients showed abnormal EEG activities. More male patients showed abnormal EEG patterns than their female counterparts. As expected the EEG findings shows more abnormalities in increased with age. Commonest EEG activity seen is slowing of activity of all the waves. Longer the duration of the dementia higher the incidence of EEG abnormalities seen in this study.

Analysing the EEG findings of 30 patients who were on medications and who were without medications, it is found to be 11 abnormal patients were without medications and 10 abnormal patients were with medications and 9 normal patients were without medications and none of them were with medication.

MMSE scoring and EEG findings and Statistically significant correlation between MMSE Scoring and EEG Findings (P <0.001).

Conclusion

In this study EEG was done for patients presenting with Dementia to a tertiary care hospital during the study period. Additionally MMSE scoring was also performed for the patients. EEG was found to be normal in 9 patients and abnormal in 21 patients. It was also found that the incidence of dementia is higher in males (56.66 %) compared to females (43.33 %).According to the age group, In this study shows maximum number of age group involving the dementia is 65-75(30%).The study shows a statistically significant correlation between MMSE Scoring and EEG Findings in patients with dementia attending a tertiary care hospital (P <0.001). Combined MMSE and EEG in dementia patients with larger group will give more information.

Conflict of Interests

The authors hereby declare there is no conflict of interests associated with this study or any of the procedures and materials used for the purpose of the study.

References

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