From mild cognitive impairment to Alzheimer's disease - influence of homocysteine, vitamin B12 and folate on cognition over time: results from one-year follow-up

BACKGROUND AND PURPOSE

People with mild cognitive impairment (MCI) have higher risk of developing dementia than the general population. Currently known risk factors for dementia include older age, low education level, gait disorders, hippocampal atrophy, and apolipoprotein E allele. Vascular risk factors may modify the neurodegenerative process. The aim of this study was therefore to assess the influence of vascular (genetic and environmental) risk factors on progression to dementia in an MCI group during a one-year period.

MATERIAL AND METHODS

Fifty-five MCI patients (30 men and 25 women) and 44 controls (25 men and 19 women) matched for age, gender and education were studied. Mild cognitive impairment was diagnosed according to Petersen criteria (Mayo Clinic Group). Neuropsychological evaluation was made. Assessed vascular risk factors included hypertension, cardiovascular disease, diabetes, cigarette smoking, hyperlipidaemia, hyperhomocysteinaemia with vitamin B12 and folate deficiency. Genetic risk factors (APOE polymorphism, C677T and A1298C MTHFR polymorphisms) were also assessed.

RESULTS

Vascular risk factors were found significantly more often in the MCI group (p = 0.041), including APOE4 allele (p = 0.018), hyperhomocysteinaemia (p = 0.012) and folate deficiency (p = 0.023). Discriminant function analysis showed that only age and hypertension are potential factors which may have an influence on progression to dementia in the MCI group within one year of prospective observation.

CONCLUSION

Vascular risk factors are associated with cognitive impairment but do not have a significant influence on progression to dementia in the MCI group.

Cerebral white matter lesions in patients with dementia - from MCI to severe Alzheimer's disease

BACKGROUND

Brain images of patients with Alzheimer's disease (AD) on magnetic resonance imaging (MRI) show white matter lesions (WML), which are attributed to degenerative changes of small vessels. These lesions are supposed to be among the factors supporting the diagnosis of probable AD; however their correlation with the severity of dementia requires further studies.

METHODS

We examined four groups of patients with cognitive impairment: Ten patients with amnestic-MCI (Mild Cognitive Impairment), 11 with mild AD (21-24 points in MMSE), 17 with moderate AD (11-20 points in MMSE) and 15 with severe AD (3-10 points in MMSE). The T2 and FLAIR MRI sequences of the brain of each patient were assessed using the White Matter Lesions Semiquantitive Rating Scale, taking into consideration the amount, size and distribution of WML.

RESULTS

WML of the brain were seen in almost all patients with AD and MCI on T2 and FLAIR sequences. The positive correlation between the patients' age and the amount and size of WML, in subcortical (T2: p<0.01, r=0.39; FLAIR: p<0.05, r=0.31) and in the periventricular region (T2: p<0.05, r=0.28; FLAIR: p<0.05, r=0.35) has been shown on both sequences. There was no correlation between the size or distribution of lesions and either hypertension or homocysteine blood level. The analysis revealed also that in both sequences, the severity of lesions in the periventricular region increased with the progression of the disease (T2: p=0.038; FLAIR: p=0.02).

CONCLUSIONS

A significant factor correlating with the location of WML in patients with MCI and AD is the age of patient. The amount and size of WML in the periventricular and subcortical regions of the brain correlates with the severity of dementia. Hypertension and hyperhomocysteinemia have no influence on the presence of described lesions.

Platelet phospholipase A2 activity in patients with Alzheimer’s disease, vascular dementia and ischemic stroke

Phospholipase A(2) (E.C. 3.1.1.4, PLA(2)) plays an essential role in metabolism of membrane phospholipids, it is related to inflammatory reactions, secretion of amyloid precursor protein and activation of NMDA receptor after ischemia. In the present study we investigated PLA(2) activity in platelets from 37 Alzheimer's disease (AD) patients, 32 vascular dementia (VaD) patients and 32 individuals with ischemic stroke as compared to 27 healthy elderly controls. PLA(2) activity was determined using radiometric assay. Mean platelet PLA(2) activity was increased in individuals with Alzheimer's disease (p < 0.001). In VaD group the enzyme activity was between the values in AD and controls, these differences being significant from both groups. In the group of patients with ischemic stroke mean PLA(2) activity was higher either 48 h after the stroke or 7 days later (in both cases p < 0.001). The results may be particularly interesting in light of the fact, that inhibitors of PLA(2) activity are known.

Vascular risk factors and intensity of cognitive dysfunction in MCI

Patients with Mild Cognitive Impairment (MCI) have a greater risk of developing dementia than general population. Lots of evidence suggests that cardiovascular risk factors appear more often in the MCI than in general population The aim of this study was to evaluate association between cardiovascular risk factors and intensity of cognitive impairment in MCI patients. We evaluated 24 MCI patients (9 women and 15 men) fulfilling Mayo Clinic Group Criteria. Taking under consideration presence of cardiovascular diseases patients were divided into two groups: first group (n=16) MCI with cardiovascular diseases and second group (n=8) MCI without cardiovascular disorders. Cognitive functions were assessed by neuropsychological tests battery including MMSE, Clock Drawing Test, Trail Making Test (TMT), Verbal Fluency Test with letters FAS, Auditory Verbal Learning Test (AVLT). In the MCI group with vascular risk factors we have found more distinct dysfunction of learning new information, recall and short-term memory than in MCI patients without vascular pathology. In conclusion we may suggest that more distinct cognitive deficit may indicate higher risk of developing dementia, that is why patients with MCI should be under special supervision, with at least annual neuropsychological evaluation.

[Melkersson-Rosenthal syndrome as a rare cause of recurrent facial nerve palsy]

Melkersson-Rosenthal syndrome is a rare cause of recurrent facial nerve palsy. The syndrome is classically characterized by a triad of signs consisting of facial edema, recurrent peripheral facial nerve paralysis, and congenital fissured tongue, although it may also present in a mono- or oligosymptomatic form. The paper presents a 24-year-old woman with right-sided peripheral facial nerve palsy and a history of left-sided episodes of facial nerve palsy. Magnetic resonance angiography of the cerebral vessels suggested compression of the right seventh and eighth cranial nerves by a vascular loop. The authors describe the patient with a complete picture of Melkersson-Rosenthal syndrome and discuss the diagnosing process and treatment.

[Inferior frontal region hypoperfusion in Parkinson disease with dementia]

INTRODUCTION

Dementia is more frequent in patients suffering from Parkinson's disease (PD) then in general population. The mechanism for mental deterioration in PD remains controversial. The aim of our study was comparison of the regional cerebral perfusion quantified by single photon emission computed tomography in patients suffering from idiopathic Parkinson's disease with and without dementia.

MATERIAL AND METHODS

We examined 49 PD patients: 22 PD patients with dementia and 27 PD patients without dementia. Dementia was recognized according to ICD-10 and DSM-IV criteria. Cognitive functions were executed by means of the Mini Mental State Examination (MMSE) and neuropsychological assessment. The Unified Parkinson's Disease Rating Scale (UPDRS) and Modified Hoehn & Yahr Scale was used to quantify the severity of PD. SPECT was performed with Siemens Diacam single--head rotating gamma camera after intravenous application of technetium 99m hexamethylpropylene amine oxime (99mTc-HMPAO). The perfusion values were expressed as cortical or basal ganglia regions of interest (ROIs)/cerebellum activity ratios.

RESULTS

In both examined group of patients the lowest uptake was in basal ganglia region, while the highest uptake was in occipital region. In the subgroup of PD patients with dementia significant hypoperfusion affecting the inferior frontal cortices was observed.

CONCLUSIONS

In Parkinson's disease with dementia hypoperfusion in inferior frontal region can be found.

[Parkinsonism in chronic occupational metallic mercury intoxication]

Parkinson syndrome occurs in the course of chemical intoxication, especially Mn, CS2, CO. It is rarely caused by chronic mercury intoxication. We present the case of 55 year old man who was exposed to metallic mercury vapor during 33 years of working in the chemical plant at the production of chlorine. On several occassions patient was removed from contact with Hg because of the symptoms of increased Hg absorption. At the age of 52 he developed hand tremor, balance and gait disturbance with bradykinesia, paresthesias of the upper extremities, neurobehavioral abnormalities, slight memory loss, and spatial disorientation. Psychoneurological examination revealed dementia, Parkinson's syndrome and ataxia of the lower limbs. Mercury excretion in the urine, which equaled 18.3 mu\g creatinine, confirmed exposure to Hg. MRI of the head revealed cortical and cerebellar atrophy. Electroneurography examination found features of subclinical peripheral sensory axonopathy of the upper limbs. Despite atypical clinical course (parkinsonismus) chronic mercury encephalopathy was diagnosed based on documented occupational exposure and diagnostic test results.