A total of 513 (1.3%) of 40,360 screened patients showed up with at least one dementia related term. Of this group, 44% were female 56% male. The mean age of the group of 513 patients extracted by key word search was 58.1 (SD= 18.9, range 19-96). Clinical diagnoses were symptomatic epilepsy in 264 (51.5%), cryptogenic in 120 (23.4%), idiopathic in 73 (14.2%), and no epilepsy in 56 (10.9%) patients. The mean age at epilepsy onset was 45.6 years (SD= 25.5, range 0-94), the average duration 13.4 years (SD= 13.4, range 0-71),
As for the diagnosis of dementia or a neurodegenerative disease condition, 65 of the 513 extracted patients (12.7%) had a definitive diagnosis of dementia, and 34 (6.6%) got the diagnosis of suspected dementia (Figure 1). The exact ICD-11 diagnoses are listed in Table 1. Table 2 summarizes the reported comorbidities for this group, the most frequent being arterial hypertension, depression, cerebral infarct and brain atrophy. Apart from the target diagnosis of dementia, 25 (4.9% of 513) patients had been given the diagnosis of mild cognitive impairment (MCI). The diagnoses of an evident or suspected neurodegenerative disease without dementia was given to 26 (5.1% of 513) and 8 (1.6% of 513) patients, respectively.
Table 1: Frequencies of different dementia diagnoses
Dementia diagnosis
|
Frequency (n=99)
|
ICD-11
|
Advanced dementia
|
2
|
6D8Z.XS25
|
Alzheimer dementia
|
7
|
6D80.Z
|
Alzheimer dementia type 2
|
2
|
6D80.0
|
Beginning dementia
|
9
|
6D8Z.XS5W
|
Dementia
|
26
|
6D8Z
|
Dementia due to Down Syndrome
|
1
|
6D85.9
|
Fronto-temporal dementia
|
1
|
6D83
|
Fronto-temporal lobar degeneration
|
2
|
8A23
|
Mixed dementia
|
3
|
6D80.2
|
Parkinson's dementia
|
2
|
6D85.0
|
Suspected Lewy-Body-dementia DD vascular dementia
|
1
|
6D82/6D81
|
Suspected Alzheimer dementia
|
3
|
6D80.Z
|
Suspected Alzheimer dementia type 1
|
3
|
6D80.1
|
Suspected beginning dementia
|
1
|
6D8Z.XS5W
|
Suspected dementia
|
24
|
6D8Z
|
Suspected Lewy-Body-dementia
|
2
|
6D82
|
Suspected Lewy-Body-dementia DD Creutzfeldt-Jakob-Disease
|
1
|
6D82/6D85.5
|
Suspected mixed dementia
|
1
|
6D80.2
|
Vascular dementia
|
7
|
6D81
|
Vascular dementia DD fronto temporal dementia
|
1
|
6D81/6D83
|
Table 2: Comorbidities of patients with dementia diagnoses
Additional diagnosis
|
Frequency (n=99)
|
Arterial hypertension
|
33
|
Depression
|
19
|
Cerebral infarct
|
16
|
Brain atrophy
|
15
|
Atrial fibrillation
|
14
|
Polyneuropathy
|
11
|
Traumatic brain injury
|
11
|
Status epilepticus
|
9
|
Coronary artery disease
|
8
|
Delirium
|
7
|
Diabetes mellitus Type 2
|
7
|
Microangiopathy
|
7
|
Hippocampal sclerosis
|
6
|
Parkinson’s disease
|
6
|
Presbycusis
|
5
|
Hypercholesteremia
|
5
|
Meningioma
|
5
|
Nicotine addiction
|
5
|
Subarachnoidal hemorrhage
|
5
|
Alcohol addiction
|
4
|
Urinary tract infection
|
4
|
Hypothyroidism
|
4
|
Pulmonary embolism
|
4
|
Kidney insufficiency
|
4
|
Sleep-apnea syndrome
|
4
|
Chronic pain syndrome
|
4
|
Tremor
|
4
|
Transposing the numbers of diagnosed or suspected dementia in the 513 extracted patients (19.3% of 513) into an estimate for all 40,360 patients whose files were screened for dementia related terms, a prevalence of 0.25% can be inferred.
The literature clearly identifies age and a late onset of epilepsy as risk factors for dementia in epilepsy. Accordingly, in the group of 513 extracted patients, the likelihood of getting a (suggested) dementia diagnosis increased with chronological age and with the age at epilepsy onset. Patients with a diagnosis of (suggested) dementia as a group were significantly older (age 71.4 ± 14.9 years vs. 54.8 ± 18.3 years, F=69.5, p<0.001) and their age at the onset of epilepsy was significantly later (age 58.2 ± 25.0 years vs. 41.7 ± 24.5 years, F= 24.6, p<0.001) than in patients without (suggested) dementia.
Taking an age of 60 years as a cut-off, 6.9% of the younger subgroup (age < 60yrs.: n=264) were affected, whereas in the older subgroup (age ≥ 60yrs.: n=249) it were 31% (Chi2 = 48.3(1) p<0.001). The odds ratio (OR) for the older versus younger group of having diagnosed or suspected dementia was 6.1 (95% CI: 3.5-10.7), the respective relative risk (RR) was significantly increased by 88.4% (RR= 1.9, p<.001, 95% CI: 1.6-2.2).
As regards the age at epilepsy onset, in the early onset subgroup (onset < age 60: n=221) 13.1% patients of this group got a (suspected) dementia diagnosis as compared to 32.0% in the late onset, subgroup (onset ≥ 60 yrs.: n=125) (Chi2 = 17.9(1) p<0.001). The odds ratio (OR) for having a diagnosis of dementia or suspected dementia was 3.1 (95% CI: 1.81-5.36) for the late onset epilepsies, and the RR for having a LOE (60 and older) and a (suspected) dementia diagnosis (n=99) was significantly increased by 88.9% in this group (RR=1.9, p<.001, 95% CI: 1.5-2.5).
Neither the diagnosis of different types of epilepsy, the year of diagnosis, the duration of epilepsy, nor gender were associated with different prevalence of a (suspected) dementia diagnosis (all p>0.1).
Finally, the files of the 99 (suspected) dementia patients were screened in regard to the question of which diagnosis came first, epilepsy or dementia, respectively whether the treating physician had made any assumption about the relation between the two diagnoses. In 8.1% of the cases the dementia diagnosis had preceded the epilepsy diagnosis, in 23.2% it was diagnosed after epilepsy, in 18.2% it appeared coincident, in 9.1% it was perceived as independent, 15.2% had no epilepsy, and in 26.3% of the cases no information or assumption was available.