Environmental noise-exposed workers: event-related potentials, neuropsychological and mood assessment.

Prolonged environmental noise exposure can induce pathogenic effects on various physical and psychosocial responses. The first aim of this study was to investigate whether long-term occupational noise exposure could affect neurophysiological, neuropsychological and emotional statuses, with particular respect to attention and working memory. The second aim was to evaluate the effects on the tactile P300 of a specific stressor (background traffic noise) vs a non-specific stress inductor (Stroop test). The comparison between a group of noise-exposed workers (traffic police officers), and a control group (office employees) did not show marked differences in cognitive and emotional profiles. The amplitude of the baseline cognitive potential (P300), recorded during a tactile (electric) discrimination task, resulted higher in noise-exposed workers than in controls, and this enhancement was associated with a lower level of trait anxiety and better mood profiles. Moreover, we found a wider P300 amplitude reduction in traffic police officers than in controls, under noisy conditions due to traffic. The effect of the Stroop test as a stress inductor was negligible and similar in the two groups. The wider amplitude of the non-auditory P300 in traffic police officers in the baseline condition could be a sign of cross-modal cerebral plasticity enhancing attentive processes in the 'stress-free' sensory channel. In addition, noise-exposed workers presented a higher cerebral sensitivity to stress selectively when they were exposed to the habitual environmental stressor.

Alpha rhythms in mild dements during visual delayed choice reaction time tasks: a MEG study.

Can simple delayed response tasks affect latency and amplitude of magnetoencephalographic midline alpha rhythms (6-12 Hz) in early dementia? We recruited 15 mild Alzheimer's disease (AD) and 10 vascular dementia (VaD) patients (paired mini mental state exam of 17-24). The control groups comprised 18 young and 22 elderly normal subjects. In the first task, a simple "cue" stimulus (one bit) was memorized along a brief delay period (3.5-5.5s) up to a "go" stimulus triggering (right or left) button press. In the second task, the "cue" stimulus remained available along the delay period. Event-related reduction in power of the alpha rhythms indexed the cortical activation (event-related desynchronization, ERD) for the trials associated with correct behavioral responses. Behavioral performances to both tasks were lower in the AD and VaD patients than in the normal subjects. In particular, just four AD and five VaD patients executed a sufficient amount of correct responses for the alpha ERD analysis, so they were included in a unique group. In both tasks, the alpha ERD peak was later in latency in the demented and normal elderly subjects than in the normal young subjects. Furthermore, the alpha ERD peak was stronger in amplitude in the demented patients than in the normal subjects. These results suggest that simple delayed response tasks during physiological recordings are quite difficult for patients even at an early dementia stage. Such difficulty may induce the abnormal amount of the related cortical activation in dementia as revealed by the alpha ERD.

Mini-mental state examination and mental deterioration battery: analysis of the relationship and clinical implications.

OBJECTIVES: To explore the associative structure between a screening test for dementia, the Mini-Mental State Examination (MMSE), and a neuropsychological battery for the detection of dementia, the Mental Deterioration Battery (MDB). DESIGN: A retrospective analysis. SETTING: Psychology unit of a general hospital in Rome, Italy. PARTICIPANTS: Three hundred consecutive outpatients and inpatients referred to our hospital on the basis of suspected cognitive impairment and evaluated between January 1999 and March 2000. MEASUREMENTS: MMSE and MDB. RESULTS: Of the 300 subjects evaluated by the MMSE score, 142 (47.3%) were considered to be cognitively healthy, and 116 (38.7%) were mildly and 42 (14.0%) moderately impaired. Factor analysis of MDB extracted three factors able to account for 75% of the total variance: a visuospatial factor, verbal memory ability, and a language skill. Using MMSE as an independent variable, a linear regression model could account for the visuospatial and language factors and a cubic regression model for the verbal memory factor. Within the normal MMSE boundaries (24-30), a dramatic decrease of verbal memory could be documented, whereas the slope is less steep in the mild impairment group (16-23). CONCLUSIONS: Our findings indicate the presence of a warning range within the normal MMSE interval. Thus, the traditional MMSE cutoff values may not be appropriate in detecting early phases of dementia. When patients score about 27 on MMSE, it should be of interest to check whether they fail only on long-term memory tests, because this could be a first signal of a preclinical condition heralding clear dementia (e.g., mild cognitive impairment).

Motor cortex excitability in Alzheimer's disease: a transcranial magnetic stimulation follow-up study.

Transient cognitive and behavioral stabilization of patients with Alzheimer's disease (AD) is the main goal of acetylcholinesterase inhibitor (AChEI) therapy. Response to treatment is variable and it is usually assessed clinically via neuropsychological scales. Functional neuroimaging could ideally permit the objective evaluation of the topographic correlates of therapy on brain functioning, but is expensive and little available on a large scale. On the other hand, neurophysiological methods such as transcranial magnetic stimulation (TMS) could offer an alternative, low-cost and risk free tool of assessing response to treatment in AD. Previous TMS studies have demonstrated hyperexcitability and asymptomatic motor cortex reorganization in the early stages of AD in patients with normal motor function. The aim of this study was to compare motor cortex functionality in 10 AD patients before and after long-term AchEIs therapy in order to monitor potential drug-related changes in cortical excitability and organization. Examined parameters of motor cortex physiology were found to be unchanged in patients with stabilized cognitive performance during the therapy. TMS, along with clinical, neuropsychological, and neuroimaging data, could be an inexpensive measure of biological progression in AD and it might supplement traditional methods to assess the effects of therapy.

Hyperhomocysteinemia, intima-media thickness and C677T MTHFR gene polymorphism: a correlation study in patients with cognitive impairment.

OBJECTIVE: Intima-media thickness (IMT) seems associated with risk of Alzheimer disease (AD). Homocysteine (hcy) is a risk factor for vascular diseases and dementia. This study aimed at investigating the possible relationship among IMT, plasma hcy and C677T methylentetrahydrofolate reductase (MTHFR) polymorphism in relation to cognitive status. METHODS: Sixty-three patients with cognitive impairment and 64 controls underwent biochemical, neuropsychological and carotid ultrasound assessment. RESULTS: After age and folate adjustment, plasma hcy correlated with both Mini Mental State Examination (MMSE) score (r=-0.7, p<0.01) and IMT (r=0.7, p<0.01). Among patients with cognitive impairment, carriers of TT677 MTHFR genotype had plasma hcy (p<0.001) and IMT (p<0.01) values higher than non carriers. Furthermore, multiple regression analysis showed that MMSE scores were associated with plasma hcy (beta=-0.3, p=0.01), IMT (beta=-0.3, p=0.01) and TT677 MTHFR genotype (beta=-0.3, p=0.02). Structural equation modelling showed that the relation between hcy levels and MMSE score was partly direct (parameter estimate=-0.6; p=0.01) and partly mediated by IMT values (parameter estimate=-0.4; p=0.03). Finally, IMT resulted associated with hypertension (parameter estimate=0.8; p<0.0001). CONCLUSION: Our findings suggest that TT677 MTHFR genotype promotes plasma homocysteine increase which in turn may favour intima-media thickening in patients with cognitive impairment. Hcy may promote neuronal damage through multiple mechanisms, including a micro-vascular damage, mediated by IMT increase, and a direct neuro-toxic effect.

Use of an Italian version of the telephone interview for cognitive status in Alzheimer's disease.

OBJECTIVES: Validation of an Italian version of the Telephone Interview for Cognitive Status (I-TICS). METHODS: Telephone administration of the I-TICS within 6 weeks of face-to-face testing with the Mini Mental State Examination (MMSE), in Probable Alzheimer's disease (AD) patients and healthy controls. Two hundred and seven consecutive outpatients with cognitive impairment were recruited from Dementia Clinic of University Campus BioMedico. Of these, 45 probable AD patients with complete data were analyzed. Other dementias, Mild Cognitive Impairment (MCI), and patients with incomplete data were excluded. The control sample consisted of 64 age- and sex-matched healthy subjects. For diagnosis, an extensive clinical evaluation, laboratory testing, brain imaging, EEG, neuropsychological battery and a depression scale were used. For I-TICS validation, telephone I-TICS and face-to-face MMSE were administered. RESULTS: The I-TICS correlated highly and linearly with the MMSE (Pearson's r=0.904). Conversion equations are provided. Sensitivity and specificity were similar between tests (area under curve=0.894 for the I-TICS; 0.966 for the MMSE). I-TICS sensitivity was 84% and specificity 86% at a cut-off score of 28. No significant difference in accuracy with the MMSE was present. Total agreement between I-TICS and MMSE was 'substantial' at 86% (Cohen's K=0.717). Repeated testing in a subset of patients showed a disease progression related decrease of 4.2 points/year (t=2.664; p=0.018) in I-TICS scores. CONCLUSION: The I-TICS is a valid instrument in clinical and research screening and monitoring of AD. Potential applications in other dementias and MCI are worth further studies.

Cognitive impairment in elderly ED patients: need for multidimensional assessment for better management after discharge.

We describe the prevalence of cognitive impairment in a population aged 65 and older requiring urgent medical services and to propose global evaluation, involving cognitive, functional and social aspects, during the emergency department (ED) visit to define an individualized care protocol. A total of 150 patients aged 65 and older attended at the ED were screened for cognitive impairment using the Mini-Mental State Examination (MMSE). Patients with an MMSE score lower or equal to 23 were included in the second step of the study, namely evaluation involving neuropsychological instruments to assess cognitive and functional status and a questionnaire exploring socioeconomic conditions and type of support need. Cognitive impairment was detected in 24 patients (16%). In no case of mild impairment had a cognitive deficit already been diagnosed. The functional and socioeconomic profile enabled proposing a strategy for better management of the patients discharged by the ED.