Search PubMed⌕ Search

Biomedical subjects

M A Ron

Publications and source records attributed to M A Ron.

At least 19 recordsLinked to original sources
PubMed1999

Correlates of executive function in multiple sclerosis: the use of magnetic resonance spectroscopy as an index of focal pathology.

Proton magnetic resonance spectroscopy (MRS) was performed in a group of patients with multiple sclerosis (MS) and matched control subjects to examine the relationship between frontal lobe pathology and performance on tests of executive function. The N-acetyl aspartate/creatine ratio (NAA/Cr) was significantly reduced in frontal lesions and/or normal-appearing white matter in the patient group compared with the control group, but choline/creatine ratios did not differ. Although MRS abnormalities and executive deficits were not correlated for MS patients as a group, a few patients with more severe abnormalities of NAA/Cr ratio performed worse than other patients on the spatial working memory test, suggesting that subtle frontal neuropathological abnormalities detected by MRS may contribute to executive deficits. Further investigation is warranted to determine the value of MRS as an index of the pathophysiological processes leading to cognitive deficit.

Adult↗
PubMed1998

Slater revisited: 6 year follow up study of patients with medically unexplained motor symptoms.

OBJECTIVE: To investigate psychiatric and neurological morbidity, diagnostic stability, and indicators of prognosis in patients previously identified as having medically unexplained motor symptoms. DESIGN: Follow up study. SETTING: National Hospital for Neurology and Neurosurgery, London--a secondary and tertiary referral hospital for neurological disorders. SUBJECTS: 73 patients with medically unexplained motor symptoms admitted consecutively in 1989-91. 35 (48%) patients had absence of motor function (for example, hemiplegia) and 38 (52%) had abnormal motor activity (for example, tremor, dystonia, or ataxia). MAIN OUTCOME MEASURES: Neurological clinical diagnosis at face to face reassessment by a neurologist and a psychiatric diagnosis after a standardised assessment interview--the schedule for affective disorders and schizophrenia--conducted by a psychiatrist. RESULTS: Good follow up data were available for 64 subjects (88%). Only three subjects had new organic neurological disorders at follow up that fully or partly explained their previous symptoms. 44/59 (75%) subjects had had psychiatric disorders; in 33 (75%) patients, the psychiatric diagnosis coincided with their unexplained motor symptoms. 31/59 (45%) patients had a personality disorder. Three subjects had developed new psychiatric illnesses at follow up, but in only one did the diagnosis account for the previous motor symptoms. Resolution of physical symptoms was associated with short length of symptoms, comorbid psychiatric disorder, and a change in marital status during follow up. CONCLUSIONS: Unlike Slater's study of 1965, a low incidence of physical or psychiatric diagnoses which explained these patients' symptoms or disability was found. However, a high level of psychiatric comorbidity existed.

Adolescent↗
PubMed1998

Neuropsychological deficits in multiple sclerosis after acute relapse.

OBJECTIVES: To examine cognitive and neurological changes and their relation to brain pathology in patients with multiple sclerosis during acute relapse. METHODS: Thirteen patients with multiple sclerosis were examined with a battery of neuropsychological tests during acute relapse and six weeks later. Their performance was compared with the performance of 10 controls matched for age and premorbid IQ. Gadolinium (Gd) enhanced MRI was also performed in patients on both occasions. RESULTS: The patients with multiple sclerosis performed significantly worse than controls on most tests of attention and memory during acute relapse and in remission. At follow up there was a significant or trend of improvement in performance on some tests of attention for patients in whom the Gd enhanced lesion load had decreased. In this subgroup of patients, their improvement also correlated significantly with the reduction in acute lesion load. CONCLUSIONS: The findings suggest that certain neuropsychological deficits detected during an acute relapse may be reversible, particularly in patients who initially have mild cognitive impairment.

Activities of Daily Living↗
PubMed1997

Interrogative suggestibility in patients with conversion disorders.

We tested the hypothesis that increased interrogative suggestibility may contribute to the shaping and maintaining of conversions symptoms. Interrogative suggestibility was measured in 12 patients with conversion disorder and 10 control patients with confirmed neurological disease matched for age, premorbid intelligence, and as closely as possible in terms of their neurological symptoms to the patients with conversion disorder. Our observations do not support the contention that individual differences in interrogative suggestibility are of importance in the etiology of conversion disorders.

Adult↗
PubMed1997

Executive function in multiple sclerosis. The role of frontal lobe pathology.

Deficits in executive function and the relationship to frontal lesion load as detected on MRI were investigated in 42 multiple sclerosis patients. A battery of neuropsychological test examining executive skills including computerized tests of planning and spatial working memory was administered to all subjects. Performance on these tests was impaired in the patient group when compared with a group of matched controls, but not all executive skills were affected to the same extent. Although a number of executive test scores correlated with the severity of frontal lesion load, it was difficult to disentangle the specific contribution of frontal lobe pathology to the impairment on executive tasks. This study highlights the difficulties in attempting to attribute specific cognitive abnormalities to focal brain pathology in the presence of widespread disease such as in multiple sclerosis.

Adolescent↗
PubMed1996

Hippocampal age-related changes in schizophrenia: a proton magnetic resonance spectroscopy study.

We have used proton magnetic resonance spectroscopy to study in vivo N-acetyl aspartate (NAA), choline and creatine in the hippocampi of 26 schizophrenics and 38 normal controls. Measurements of NAA suggest that age-related neuronal loss occurs at a similar rate in schizophrenics and controls. On the other hand, we observe in schizophrenics age-related choline abnormalities not present in controls. We suggest that these age-related changes may be related to an abnormal myelination process and contribute to the observed clinical deterioration associated with schizophrenia.

Adolescent↗
PubMed1996

Memory impairment in schizophrenia: its' relationship to executive function.

The presence of memory impairment in schizophrenia has frequently been documented but much less attention has been given to the qualitative aspects of this impairment and its association to executive function. Using a cognitive-process approach, we examined memory and executive function in 25 patients who met DSM-III-R criteria for schizophrenia. Patients were matched with 25 healthy volunteers. The schizophrenic group was found to have a significant impairment in immediate memory, with relatively spared long-delay memory. Performance on verbal learning and recognition memory was similar to that of controls. Memory deficits were present irrespective of the encoding strategies used and were unrelated to chronicity. In addition, the schizophrenics performed worse than controls on tests of executive function, but the degree of impairment was greater on tests of response initiation and suppression. This pattern of performance resembled that found in patients with subcortical or frontal lesions which was supported by some significant correlations between aspects of memory and executive function. Our results suggest that in schizophrenia, specific executive functions may make a selective contribution to the pattern of memory performance in schizophrenia which is subserved by frontal and to a lesser extent hippocampal/diencephalic systems.

Adult↗
PubMed1996

Pathological laughing and crying.

OBJECTIVE: To review the clinical features, neurobiological correlates and treatment of pathological laughing and crying. METHOD: Selective literature review. RESULTS: Attacks of involuntary, irresistible laughing or crying have long been recognised as sequelae of brain damage. There is controversy about the clinical features of these attacks, the stimuli that provoke them and their relation to affective disorder. The pathophysiology of pathological laughing and crying is still unclear. It can occur in the presence of focal as well as diffuse brain disease. Treatment with antidepressant medications has been found to be of benefit in patients with cerebrovascular disease and multiple sclerosis. CONCLUSIONS: Clinicians should remain vigilant for these symptoms, and offer effective treatments, such as antidepressants, where indicated. Further research is needed to delineate the underlying neurobiological correlates of pathological laughing and crying. The efficacy of both pharmacological and non-pharmacological interventions requires critical evaluation.

Brain↗
PubMed1995

Proton magnetic resonance spectroscopy of systemic lupus erythematosus involving the central nervous system.

We examined 13 patients with neurological manifestations of systemic lupus erythematosus (SLE) based on previous and/or current neurological or psychotic episodes by magnetic resonance imaging (MRI) and proton magnetic resonance spectroscopy (MRS) together with psychiatric and cognitive assessment. MRI was abnormal in 7 patients, showing high signal lesions in the white matter and/or cerebral atrophy. Proton MRS centred on white matter lesions in 5 patients showed a reduction in the N-acetyl aspartate creatine ratio compared with normal appearing white matter in the SLE group and in 10 healthy controls. This pattern of abnormality does not allow differentiation of SLE lesions from the chronic plaques occurring in multiple sclerosis. There was a very high incidence of current psychiatric morbidity in the SLE group, namely in 12 of the 13 patients. There was no correlation between the presence of current psychiatric involvement and/or cognitive dysfunction and abnormalities detected with MRI or MRS.

Adult↗
PubMed1995

Proton magnetic resonance spectroscopy: an in vivo method of estimating hippocampal neuronal depletion in schizophrenia.

Diffuse loss of cortical volume and ventricular enlargement have been demonstrated in schizophrenia using imaging. In addition, histological studies have provided evidence that the number of neurons in the medial temporal lobe structures is reduced and that the cytoarchitecture is abnormal. In an attempt to correlate these histological findings with in vivo estimates of neuronal integrity we have studied the concentration of the neuronal marker N-acetyl aspartate (NAA) in the hippocampi of schizophrenics using in vivo Magnetic Resonance Spectroscopy (MRS). Compared with a group of healthy volunteers schizophrenics showed a 22% loss of NAA in the left hippocampus. Two other metabolites, choline and creatine showed bilateral reduction in schizophrenics and these achieved significance in the left hippocampus. These results indicate a significant depletion of NAA in schizophrenia and are in close agreement with the reported neuronal loss in the hippocampus detected histologically. We propose that in vivo MRS is a valid measure of integrity of neuronal populations in schizophrenia.

Adult↗
PubMed1995

Psychotic and depressive symptoms in Parkinson's disease. A study of the growth hormone response to apomorphine.

BACKGROUND: The growth hormone (GH) response to apomorphine, thought to reflect central dopaminergic receptor sensitivity, has been reported as enhanced in acute schizophrenia. We investigated this response in relation to the psychotic episodes associated with Parkinson's disease (PD). METHOD: The GH response to apomorphine was measured in three groups of patients with Parkinson's disease: those currently psychotic (n = 9), those with a past history of psychosis (n = 7) and those who had never been psychotic (n = 8). RESULTS: Apomorphine-induced GH response was not related to psychosis but was unexpectedly associated with measures of depression. CONCLUSIONS: Visual hallucinations were a prominent feature in the psychotic patients and the atypical nature of these psychoses might explain why we found no evidence of dopaminergic sensitivity. Serotonergic dysfunction would be in keeping with this. Dopaminergic mechanisms may contribute to the minor depressive symptomatology seen in PD.

Aged↗
PubMed1994

Volumetric MRI measurements in bipolars compared with schizophrenics and healthy controls.

Twenty-six patients with RDC bipolar disorder were compared with a previously reported group of 48 RDC schizophrenics and 34 healthy controls, using volumetric MRI measurements of cerebral, cortical and sulcal volumes. The bipolar group appeared no different from the controls, and both of these groups had significantly larger cerebral and cortical volumes than the schizophrenics. Our previous report of a significantly reduced cortical volume in the schizophrenic group, with a corresponding increase in the volume of sulcal fluid is, therefore, not a generalized feature of psychotic illness but may be more specific to schizophrenia.

Adult↗