Are the basal ganglia involved in language comprehension? A neurophysiological attempt

Deficits of language comprehension in non-demented patients with Parkinson's disease (PD) have been observed. These alterations concern verbal fluency, the semantic domain and the cognitive-linguistic flexibility. An involvement of the nucleus candatus in linguistic comprehension has been hypothesized. The event-related potentials (ERPs) represent an electrophysiological tool for studying the global cognitive state (P300) and linguistic functions of semantic and syntactic postlexical integration (N400 and P600, respectively). To evaluate language comprehension in patients with PD by means of ERPs and neuropsychological evaluation and to compare these results with those obtained in a case of restless legs syndrome (RLS) secondary to ischemic stroke in the basal ganglia region

Visual and auditory event related potentials in Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is classically described as an upper and lower motor neuron disease without clinical sensory disorders. Various studies have been conducted to explore and understand motor impairment but in the last years also cognitive functions have drawn attention in ALS patients investigating extra-motor involvment. Recent neuropsychological studies have been carried out to evaluate specific cognitive dysfunction also supported by MRI, PET and SPECI findings. All papers report subtle cognitive impairment especially related to the frontal lobe functions. Gil et al (1995) performed an auditory ERPs study and they found 60% of patients had P300 delayed latency. To further investigate the relationship between ALS and cognitive function, visual and auditory oddball ERPs were recorded in 10 patients by using 30 electrodes. Attention was focused on latency and amplitude of P300 and on its topographic distribution. Neuropsychological evaluation allowed to test the cognitive status of patients and psychometric tests were selected to assess intelligence, executive functions, attention, memory, word fluency, visuo-motor and visual-constructive skills. Motor disability was scored by ALS Severity Scale including bulbar and spinal score. Depression state was evaluated by using Hamilton Scale. Results of ERPs were compared to 10 healthy age-matched controls. Preliminary data show abnormalities of P300 in about 50% of patients. Correlations between visual and auditory P300 latency and amplitude, psychometric tests, disease duration, physical disability and depression will be discussed

Visual and auditory event-related potentials in sporadic amyotrophic lateral sclerosis

Objectives: To investigate the relationship between amyotrophic lateral sclerosis (ALS) and cognitive function by means of oddball event-related potentials (ERPs) and to determine the usefulness of this methodology in the cognitive status assessment of physically disabled patients. Methods: Visual and auditory oddball ERPs were recorded in 16 consecutive sporadic ALS patients. A comprehensive battery of neuropsychological (NP) tests assessed intelligence, executive functions, attention, memory, word fluency, visuo-motor and visual-constructive skills. Results: All patients performed visual and auditory ERPs and 75% of cases showed abnormal N200 and/or P300 waves. Ten patients (62.5%) carried out the entire psychometric evaluation with significant impairment on tests of executive function and attention. A significant correlation between delayed visual (P&lt;0.04) and auditory (P&lt;0.04) P300 latency and impaired NP tests was found. Conclusions: In agreement with literature data, our findings confirm the hypothesis of cognitive impairment in ALS patients especially on attention and executive functions suggesting a more extensive degeneration beyond the motor areas. ALS causes severe physical disabilities and such a condition may interfere with NP testing. Thus, the P300 seems to be a useful tool for the assessment of cognition and attention when severe physical deficits are present.</br

Neuropsychophysiological findings in a case of long-standing overt ventriculomegaly (LOVA)

Long-standing overt ventriculomegaly in adults (LOVA) is a clinical entity characterized by chronic hydrocephalus with infant onset, slow evolution and clinical disturbances during adulthood. Few cases are reported in literature describing the evident contrast between the severity of hydrocephalus and the relatively spared neurological functioning and cognitive aspects. The authors describe a 59-year-old man with congenital hydrocephalus complaining of persistent gait impairment. Neurological examination showed a mild paraparesis, severe higher cortical function impairment but relatively sparing of daily living activity. Computed tomography (CT) and magnetic resonance imaging (MRI) revealed a very remarkable ventriculomegaly compressing the brain cortex but sparing the cerebellum and the brainstem. Brain Single Photon Emission Computer Tomography (SPECT) showed a prevalent cerebellar perfusion as well. Neuropsychological testing was consistent with severe cognitive deterioration and attention disorders. Language and praxis functions seemed to be preserved. Auditory oddball ERPs (P300) showed morphological abnormalities especially of late components. This case report demonstrates in vivo the level of adaptation to which human brain can reach under chronic mechanic stress conditions. The striking poor cerebral parenchyma representation and the relatively spared language and praxic abilities account for a functional reorganization of residual structures due to the neural plasticity

Longitudinal study of cognitive dysfunction in multiple sclerosis: neuropsychological, neuroradiological, and neurophysiological findings

Objective: (1) To assess cognitive function and cerebral magnetic resonance imaging (MRI) involvement in relapsing-remitting multiple sclerosis; (2) to monitor disease evolution, cognitive dysfunction, and cerebral lesion burden over time (mean 8.5 year follow up period); (3) to study the relation between clinical, neuropsychological, and MRI data. On follow up assessment, visual and auditory oddball event related potentials (ERPs) were recorded as psychophysiological evaluation of cognitive status. Correlations between neuropsychological, MRI, and ERP data were also analysed. Methods: Neuropsychological study assessed verbal and non-verbal IQ, deterioration index (DI) from WAIS subtests, conceptual reasoning, attention, verbal and visuospatial short-term and long term memory. MRI assessment detected presence of demyelinating lesions by using a semiquantitative method as well as cortical and subcortical atrophy over time. Results: Attention, short-term and long term visuospatial memory were mildly impaired at baseline and remained unaltered longitudinally. At retesting a significant worsening of verbal long term memory (p=0.023), DI presence (p=0.041) and the increase of supratentorial and subtentorial MRI lesions load (p=0.001) emerged. Expanded disability status scale score correlated significantly with total lesion burden at both evaluations (p=0.043 and p=0.024 respectively). Temporal, occipital, and frontal horn lesions as well as cortical atrophy correlated significantly with attention and memory tests at baseline. Follow up assessment revealed significant correlation between cortical atrophy and attention as well as visuospatial short-term memory; spatial long term memory correlated significantly with lesions in body of lateral ventricle and frontal lobe. ERP study showed P300 latency abnormalities in 75% of patients, involving specifically more visual P300 (58.4 % of cases) than auditory wave (41.6 %). Visual P300 latency and amplitude correlated significantly with DI and auditory P300 latency with frontal horn and brain stem lesions. Conclusions: These findings revealed mild cognitive impairment in MS patients particularly consistent with slowing information processing over time. Increased MRI lesions do not correlate with the clinical course of the disease and cognitive deficit evolution. Thus, cognitive dysfunction could be related to disease peculiarity and not to the time course. Correlations between P300, neuropsychological, and MRI findings provide further information about ERP application to examine cognitive impairment in MS and probably to investigate their neural origin.</br