Biomedical subjects

M Didic

Publications and source records attributed to M Didic.

7 recordsLinked to original sources

PubMed2004

Evaluation of visual recognition memory in MCI patients.

BACKGROUND: Neurofibrillary tangles seen early in Alzheimer disease (AD) initially appear in a subregion of the perirhinal cortex. In the monkey, damage to the perirhinal cortex impairs performance on visual recognition memory tasks. The authors evaluated impairment of visual recognition memory as a potential early diagnostic marker of AD. METHODS: The authors developed a visual delayed matching-to-sample task (DMS48) designed to assess visual recognition memory in humans. Twenty-three patients fulfilling the criteria of amnestic mild cognitive impairment (MCI) (mean Mini-Mental State Examination [MMSE]: 26.6, SD = 1.6) were recruited. All underwent a full neuropsychological evaluation, which included the Free and Cued Selective Reminding (FCSR) test. Their performance was compared with that of 10 patients with mild AD, 20 patients with moderate AD, 20 patients with Parkinson disease (PD), and 40 age-matched controls. RESULTS: Control subjects and patients with PD performed close to ceiling. Patients with mild AD had very low scores, while patients with moderate AD answered at random. MCI patients obtained scores that were between those of control subjects and patients with mild AD (78%, SD = 16%). MCI patients who failed on the DMS48 had lower scores on free recall (p < 0.05) and received less benefit from cueing (p < 0.01) on the FCSR than the other MCI, suggesting a profile of genuine memory impairment related to medial temporal lobe lesions. CONCLUSION: The DMS48, a test of visual recognition memory, is impaired early in the course of patients with MCI. Further studies are necessary to determine whether the evaluation of visual recognition memory may contribute to the identification of patients with AD.

Aged↗

PubMed2004

[The human perirhinal cortex].

The perirhinal cortex is a structure that lies within the medial temporal lobe. In the present paper, we review current knowledge of the anatomical boundaries and functional correlates of this structure. In the past decade, numerous animal studies have attempted to understand the contribution of the perirhinal cortex to memory. Taken together, they suggest that the perirhinal cortex is crucially involved in recognition memory. This function appears to be independent from those assumed to be subserved by the hippocampus. In humans, data are scarce but tend to corroborate results found in the animal literature. The perirhinal cortex appears to support context-free (non-episodic) knowledge, such as general knowledge about the world and "item-specific" memories. Models of declarative memory that take into account the specific contribution of the perirhinal cortex are discussed, along with their potential application to early cortical neurodegenerative disorders.

Animals↗

PubMed1999

[Progressive focal cortical atrophies].

Progressive focal cortical atrophies are degenerative conditions characterised by the insidious onset and gradual exacerbation of an impairment in a single cognitive domain related to circumscribed cerebral atrophy. Several focal cortical syndromes with deficits in the realm of cognition are reviewed: progressive impairment of language (primary progressive aphasia), speech (progressive anarthria), semantic memory (semantic dementia), episodic memory (pure progressive amnesia), vision (progressive perceptual or visuo-spatial deficits) and gesture (progressive apraxia). These conditions are histologically heterogeneous and can be associated with focal non-specific neuronal loss and gliosis with some spongiform changes (non-specific lesions), pathological features of Pick's disease (inclusion bodies and swollen neurones) or Alzheimer's disease (AD) (senile plaques and neurofibrillary tangles). A relationship between neuropsychological profiles and lesional types emerges from this review of the literature. Non-fluent primary progressive aphasia, semantic dementia and progressive anarthria are usually associated with non-specific lesions and Pick-type pathology. Progressive disorders of episodic memory and progressive visuo-spatial deficits are more often related to AD. If adequate clinical characterisation can determine the underlying disorder, it appears even more important to establish the neuropsychological profile in patients with cortical degenerative disease. Progressive deficits of only one domain of cognition may well be due to preferential involvement of anatomically and functionally defined neural systems and could therefore be considered as "system atrophies". There remains no doubt that these syndromes are particularly well suited models for studies on the relationship between cerebral functions and their neural substrate.

Aged↗

PubMed1998

A permanent pure amnestic syndrome of insidious onset related to Alzheimer's disease.

A 55-year-old patient experienced a pure amnestic syndrome of insidious onset that worsened progressively. Subsequently, her memory disorder stabilized and remained her only cognitive impairment for several years. She ultimately developed more widespread cognitive decline and terminal dementia. Postmortem examination 18 years after the onset revealed numerous senile plaques and neurofibrillary tangles consistent with Alzheimer's disease. A permanent pure amnestic syndrome of insidious onset may represent a further type of focal cerebral degeneration.

Alzheimer Disease↗

PubMed1998

Progressive loss of speech: a neuropsychological profile of premotor dysfunction.

Several patients with 'progressive loss of speech output' or 'progressive anarthria' of degenerative origin have been reported in the literature. We report 5 clinical cases with slowly progressive loss of speech output and initially no deficit in other cognitive domains. The early clinical features were analysed in an attempt to identify the anatomo-functional systems implied in the degenerative process. The first phase of the disorder was characterised by impaired articulation consistent with speech apraxia, telegraphic style and a difficulty to elaborate a series of orofacial or hand movements. It is argued that these symptoms result from an impairment of complex motor processing due to dysfunction of the ventral premotor system. In the second phase, a decrease in spontaneous speech and self-initiated action was combined with exaggerated dependency on external stimuli, interpreted as dysfunction of the dorsal premotor system. We suggest that the neuropsychological profile of the disorder may result from progressive degeneration of the premotor cortex.

Aged↗

PubMed1996

[2 cases of frontal dementia with non-specific histological lesions: clinico-pathological and nosological discussion].

We report two cases of "frontal lobe dementia", patho-anatomically defined by non-specific as neuronal loss, gliosis and spongosis. The review of the literature permit to discuss the clinical picture of "fronto-temporal dementia" in regard to neuropathological basis. Further, the boundaries with Pick's disease, Kraepelin disease, subcortical gliosis and the "prions diseases" are considered. Without more precise nosological status, tacking in count the great variability of the clinical signs, we can concluded that, at present time, the term of frontal type dementia with "non-specific histological features", that underlines the neuropathological characteristics is the most appropriate to define this clinico-pathological entity.

Aged↗

PubMed1992

[Early detection of morphologic-functional changes in the airways using a simple method of inhalation scintigraphy].

In order to validate a method of inhalation scintigraphy with 99mTc-labeled human serum albumin in the early diagnosis of morphologic-functional changes of the airways 35 volunteers and patients (12 healthy non-smokers and smokers each, 11 patients with bronchitis) were studied. Deposition of the aerosol immediately after inhalation was calculated quantitatively by a ROI technique and qualitatively (scoring of central deposition, homogeneity, and recognizability of lung outline). Additionally, the regional clearance of the inhaled aerosol was determined by continuous lung imaging up to 60 min (mainly regional mucociliary removal rates). Discrimination between healthy volunteers and patients with bronchitis was possible by means of deposition patterns immediately after inhalation. On the other hand, no differences could be recognized in this way between healthy non-smokers and smokers. Regional mucociliary removal was higher in non-smokers than in smokers, but there was no difference between smokers and patients with bronchitis.

Adult↗