The self-organized map, an architecture suggested for artificial neural networks, is explained by presenting simulation experiments and practical applications. The self-organizing map has the property of effectively creating spatially organized internal representations of various features of input signals and their abstractions. One result of this is that the self-organization process can discover semantic relationships in sentences. Brain maps, semantic maps, and early work on competitive learning are reviewed. The self-organizing map algorithm (an algorithm which order responses spatially) is reviewed, focusing on best matching cell selection and adaptation of the weight vectors. Suggestions for applying the self-organizing map algorithm, demonstrations of the ordering process, and an example of hierarchical clustering of data are presented. Fine tuning the map by learning vector quantization is addressed. The use of self-organized maps in practical speech recognition and a simulation experiment on semantic mapping are discussed. >

The self-organizing map

Objective
The purpose of this paper is to provide a comprehensive review of information accumulated over the past 26 years regarding the psychometric properties and utility of the Mini-Mental State Examination (MMSE).

Participants
The reviewed studies assessed a wide variety of subjects, ranging from cognitively intact community residents to those with severe cognitive impairment associated with various types of dementing illnesses.

Main Outcome Measures
The validity of the MMSE was compared against a variety of gold standards, including DSM-III-R and NINCDS-ADRDA criteria, clinical diagnoses, Activities of Daily Living measures, and other tests that putatively identify and measure cognitive impairment.

Results
Reliability and construct validity were judged to be satisfactory. Measures of criterion validity showed high levels of sensitivity for moderate-to-severe cognitive impairment and lower levels for mild degrees of impairment. Content analyses revealed the MMSE was highly verbal, and not all items were equally sensitive to cognitive impairment. Items measuring language were judged to be relatively easy and lacked utility for identifying mild language deficits. Overall, MMSE scores were affected by age, education, and cultural background, but not gender.

Conclusions
In general, the MMSE fulfilled its original goal of providing a brief screening test that quantitatively assesses the severity of cognitive impairment and documents cognitive changes occurring over time. The MMSE should not, by itself, be used as a diagnostic tool to identify dementia. Suggestions for the clinical use of the MMSE are made.

The mini-mental state examination: a comprehensive review.

https://www.thelancet.com/pdfs/journals/lancet/PIIS0140-6736(06)68880-6.pdf

Mild cognitive impairment

The NINCDS-ADRDA and the DSM-IV-TR criteria for Alzheimer's disease (AD) are the prevailing diagnostic standards in research; however, they have now fallen behind the unprecedented growth of scientific knowledge. Distinctive and reliable biomarkers of AD are now available through structural MRI, molecular neuroimaging with PET, and cerebrospinal fluid analyses. This progress provides the impetus for our proposal of revised diagnostic criteria for AD. Our framework was developed to capture both the earliest stages, before full-blown dementia, as well as the full spectrum of the illness. These new criteria are centred on a clinical core of early and significant episodic memory impairment. They stipulate that there must also be at least one or more abnormal biomarkers among structural neuroimaging with MRI, molecular neuroimaging with PET, and cerebrospinal fluid analysis of amyloid beta or tau proteins. The timeliness of these criteria is highlighted by the many drugs in development that are directed at changing pathogenesis, particularly at the production and clearance of amyloid beta as well as at the hyperphosphorylation state of tau. Validation studies in existing and prospective cohorts are needed to advance these criteria and optimise their sensitivity, specificity, and accuracy.

/pdf/research-criteria-for-the-diagnosis-of-alzheimer-s-disease-1jpda3ww0z.pdf

Research criteria for the diagnosis of Alzheimer's disease: revising the NINCDS–ADRDA criteria

Standardization of terminology used to describe the pattern and course of MS is essential for mutual understanding between clinicians and investigators. It is particularly important in design of, and recruitment for, clinical trials statistically powered for expected outcomes for given patient populations with narrowly defined entry criteria. For agents that prove safe and effective for MS, knowledge of the patient populations in definitive clinical trials assists clinicians in determining who may ultimately benefit from use of the medication. An international survey of clinicians involved with MS revealed areas of consensus about some terms classically used to describe types of the disease and other areas for which there was lack of consensus. In this report, we provide a summary of the survey results and propose standardized definitions for the most common clinical courses of patients with MS.

Defining the clinical course of multiple sclerosis Results of an international survey

“Every man takes the limits of his own field of vision for the limits of the world.” SCHOPENHAUER, Psychological Observations: Studies in Pessimism . The primary purpose of this paper is to explain a simple, clinically useful test for visual neglect. The results of this test, which was standardized with normal subjects and presented to patients with unilateral cerebral lesions, shed light on the nature of visual neglect. In this paper the term “visual neglect” refers to a defective and, therefore, a reduced ability to attend to one or more components of the visual world.

A simple test of visual neglect

Progressive supranuclear palsy (Steele et al.) has a characteristic pattern of dementia: (1) forgetfulness, (2) slowing of thought processes, (3) emotional or personality changes (apathy or depression with occasional outbursts of irritability), and (4) impaired ability to manipulate acquired knowledge. In many neurological disease states associated with subcortical pathology a similar pattern of dementia exists. The neurobehavioural changes of progressive supranuclear palsy thus typify a clinical pattern which may be referred to as subcortical dementia. The subcortical dementias have a striking clinical resemblance to the dementia which occurs after bifrontal lobe disease. However, the subcortical dementias can be clearly distinguished clinically from cortical dementias, other than frontal dementias. We propose as a tentative hypothesis that there may be common pathophysiological mechanisms underlying the subcortical dementias—in particular, disturbances of timing and activation. There are immediate practical implications of this hypothesis: drugs which have an effect on subcortical timing and activating mechanisms may be useful in the treatment of subcortical dementias.

https://jnnp.bmj.com/content/jnnp/37/2/121.full.pdf

The `subcortical dementia' of progressive supranuclear palsy

The concept of mild cognitive impairment (MCI) draws attention to cognitive changes not severe enough to warrant the diagnosis of dementia. As used today, it covers many pathological disorders and characterises a diverse population of patients who attend memory clinics. Our concern is the underlying heterogeneity. We suggest that it will soon be possible (if it is not already) to identify the underlying pathological disorders before the affected patients meet the criteria of dementia, thanks to specific neuropsychological assessments, neuroimaging, and biomarkers. In particular, patients with Alzheimer's disease (AD), the most important subgroup of patients with MCI, can already be identified before appearance of the fully developed clinical dementia syndrome. Accordingly, this paper proposes diagnostic criteria for "prodromal AD".

https://www.thelancet.com/pdfs/journals/laneur/PIIS1474-4422(04)00710-0.pdf

Amnestic MCI or prodromal Alzheimer's disease?

Clinica;l Neurology of Aging is a comprehensive text and reference work that covers the scientific foundations and also offers much practical clinical advice on the diagnosis and management of neurological disorders in the aged. The book is divided into six sections: Scientific Basis of Geriatric Neurology, Clinical Examination and Diagnostic Studies, Mental Status, Special Senses, Motor Control and Peripheral Nerve Function, and Common Neurologic Conditions in the Elderly. This thorough revision of a well-established text includes new chapters on competency and ethics, problems of daily living, pychopharmacology, and stability and falls. Written in an accessible style, this book will be invaluable to clinicians and neurologists who treat elderly patients.

Clinical Neurology of Aging

A new form of language therapy has been used successfully with aphasic patients who had severe, long-term, stable defects and for whom other forms of therapy had failed. One explanation for these results suggests that latent language capacities of the nondominant hemisphere may be stimulated.

Martin L. Albert

Papers

A simple test of visual neglect

The `subcortical dementia' of progressive supranuclear palsy

Amnestic MCI or prodromal Alzheimer's disease?

Clinical Neurology of Aging

Melodic intonation therapy for aphasia.