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At least 667 records · Page 37Linked to original sources
PubMed1988

The effects on auditory function of damage to the pontine olivo-cochlear bundle in man.

A patient with multiple sclerosis (MS) in whom a lesion developed in the pons between successive nuclear magnetic resonance image scans (MRI) is described. The patient developed intolerance of loud sounds, with distorted perception of speech and music, and abnormalities of stapedius reflex threshold, masked speech audiometry, and masking level difference assessment in the presence of an unchanged pure tone threshold. These abnormalities partially resolved over a number of months. It is postulated that the efferent olivo-cochlear bundle was involved on one side of the pons and the abnormalities are interpreted in terms of bilateral removal of inhibition from the hair cells of the cochlea.

Adult↗
PubMed2004

Temporal kinetics of prefrontal modulation of the extrastriate cortex during visual attention.

Single-unit, event-related potential (ERP), and neuroimaging studies have implicated the prefrontal cortex (PFC) in top-down control of attention and working memory. We conducted an experiment in patients with unilateral PFC damage (n = 8) to assess the temporal kinetics of PFC-extrastriate interactions during visual attention. Subjects alternated attention between the left and the right hemifields in successive runs while they detected target stimuli embedded in streams of repetitive task-irrelevant stimuli (standards). The design enabled us to examine tonic (spatial selection) and phasic (feature selection) PFC-extrastriate interactions. PFC damage impaired performance in the visual field contralateral to lesions, as manifested by both larger reaction times and error rates. Assessment of the extrastriate P1 ERP revealed that the PFC exerts a tonic (spatial selection) excitatory input to the ipsilateral extrastriate cortex as early as 100 msec post stimulus delivery. The PFC exerts a second phasic (feature selection) excitatory extrastriate modulation from 180 to 300 msec, as evidenced by reductions in selection negativity after damage. Finally, reductions of the N2 ERP to target stimuli supports the notion that the PFC exerts a third phasic (target selection) signal necessary for successful template matching during postselection analysis of target features. The results provide electrophysiological evidence of three distinct tonic and phasic PFC inputs to the extrastriate cortex in the initial few hundred milliseconds of stimulus processing. Damage to this network appears to underlie the pervasive deficits in attention observed in patients with prefrontal lesions.

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PubMedDate not supplied

Training to improve awareness of disabilities in clients with unilateral neglect.

OBJECTIVE: Awareness of disabilities is known to be a central problem of rehabilitation among clients with large right cerebrovascular lesions and unilateral neglect. The aim of this study was to evaluate the effect of an intervention program focused on improving the awareness of disabilities in four participants with unilateral neglect. The intervention program developed for this study was based on the assumption that awareness of disabilities is a prerequisite for being able to learn and use compensatory techniques in the performance of activities of daily living (ADL). METHOD: The study followed a single-case experimental ABA design. The Assessment of Awareness of Disability was used to measure awareness of disabilities; the Assessment of Motor and Process Skills was used to measure ADL ability; and neuropsychological tests were used to assess unilateral neglect and sustained attention. The intervention program used meaningful and purposeful occupations as therapeutic change agents to improve awareness of disabilities. RESULTS: Awareness of disabilities and ADL ability improved in all four participants; unilateral neglect decreased in three participants; and sustained attention improved in two participants. CONCLUSION: The preliminary findings indicate that training to improve awareness of disabilities might improve the ability to learn the use of compensatory techniques in the performance of ADL in clients with unilateral neglect. The effects of the intervention strategy need to be evaluated further in future research.

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PubMed2000

Cognitive dysfunction in obsessive-compulsive disorder.

OBJECTIVE: Assessment of cognitive functions among obsessive-compulsive disorder (OCD) patients would help in understanding the neurobiology and brain areas involved in that disorder. The objective of this work was to study the cognitive dysfunction in OCD patients and to identify its correlation with both the clinical picture and the severity of the disorder. METHOD: Neuropsychological and electrophysiological event-related potentials were tested in 30 OCD patients and compared with 30 normal volunteers of a matched gender, age and education. RESULTS: Results showed a defective visuospatial recognition, which worsens with chronicity, deteriorated set-shifting abilities, overfocused attention to irrelevant stimuli and delayed selective attention to relevant tasks. Mild cases showed better selective attention than severe cases. Obsessive cases had a defective visual memory, while compulsive cases had delayed perception of task relevant stimuli. Mixed cases showed disturbed information-processing both early and late. CONCLUSION: OCD patients have a characteristic pattern of cognitive dysfunction that differs among patients of varied severity, chronicity and symptom type. We suggest a striatofrontoparietal neural pathophysiology. OCD seems to be a heterogeneous disorder, both clinically and pathophysiologically.

Adolescent↗
PubMed2000

Mechanisms of functional restoration after brain injury.

The mechanisms accounting for clinical improvement after brain injury are still a matter of debate. Better knowledge of the recovery process is important for it might be influenced by therapy. This article reviews a number of studies devoted to the physiopathology of recovery from aphasia and visuo-spatial neglect after the acute stage, using various methods (cerebral blood flow and metabolism measurements, dichotic listening, transcranial Doppler ultrasonography, functional magnetic resonance imaging) with special reference to the contribution of methods using activation procedures.

Brain Injuries↗
PubMed2004

[Neurocognitive abilities in schoolchildren with periventricular leukomalacia. Preliminary results in 15 patients].

INTRODUCTION: Apart from chronic motor disorder and the possible sensory deficits (visual, propioception) associated to periventricular leukomalacia (PVL), disorders involving the integration of higher functions due to bilateral injury to the occipital parietal junction are relatively common. AIMS: Our aim was to further our knowledge of the neuropsychological characteristics of this non progressive cerebral motor disorder. Patients and methods. We analysed a sample of 15 patients with spastic diplegia due to PVL who did not present mental retardation (verbal IQ> 75 and mean verbal IQ= 91, WISC R) in order to evaluate their visual gnosis praxis, verbal and visual memory, psycholinguistic and attentional capabilities. RESULTS: Disorders involving visuospatial integration and visual constructive memory are frequent. Long term verbal memory is poor (in fact in some cases it is clearly deficient), but can be improved with associative learning. They do not present any difficulties regarding attention and some subjects display deficiencies in the pragmatic use of language. This research is still underway and the findings presented here are preliminary. CONCLUSIONS: The neuropsychological profile of the diplegic children who were studied shares the characteristics of non verbal learning disorder. The declarative memory disorder observed in several of the subjects in our sample, who were all born premature and below weight, can be accounted for by a bihippocampal pathology or by a dysexecutive disorder.

Adolescent↗
PubMed1989

[Neglect--the frequently neglected syndrome of neglect].

In daily clinical practice "neglect" is the term for a syndrome following a right parietal lesion with inability of the patient to concentrate on events on the left side. A patient is described who was admitted for headaches and in whom neurologic investigation revealed left sided neglect as the only sign. A glioma of the right hemisphere was found. The clinical search for neglect is described and possible mechanisms are discussed. Neglect is regarded as a disturbance of directed attention. The arguments in favour of attributing dominance for this function to the right hemisphere are presented.

Brain Neoplasms↗
PubMedDate not supplied

[Anterior choroid artery syndrome with neuropsychological and oculomotor disorders].

A patient with infarct in the region of the right anterior choroidal artery presented neuropsychological signs corresponding to a minor hemisphere syndrome and disorders of horizontal oculomotricity similar to those obtained in unilateral parietal-occipital lesions. An anatomic interpretation of the latter finding is attempted.

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