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Biomedical subjects

J M Annoni

Publications and source records attributed to J M Annoni.

28 records · Page 2Linked to original sources

The contribution of attentional mechanisms to an irregularity effect at the graphemic buffer level.

This study analyzes acquired dysgraphia observed in a French-speaking woman. The results point to an impairment of the graphemic buffer, i.e., the processing stage where abstract orthographic representations are temporarily stored while planning the written production. However, the spelling errors were more frequent in the irregular than in the regular words. A qualitative analysis of the errors in the irregular misspelled words showed that, in general, these were not "regularization" errors, but rather the same characteristics as the phonologically implausible errors found in the regular words, such as letters substitutions, deletions, additions, and transpositions. Furthermore, in a list of regular and irregular words of same length and graphemic structure, the errors not only tended to concentrate on the irregularity itself but also tended to be more frequent elsewhere in the irregular words compared to the regular words. These finding are discussed in terms of a post-lexical sensitivity to irregular spelling. It is also shown that when focusing attention on the irregularity becomes necessary, this can cause a detriment to the surrounding graphemic constituents. Interaction between attentional resources and processing of orthographic representations at the graphemic buffer level is considered.

Aged↗

Medical treatment of migraine: from mechanisms of action to contraindications.

Management of migraine patients with or without aura must include appropriate medication to treat the attack and long-term preventive therapy, especially if the frequency of the attacks is greater than 2-4 per month. In both cases the choice of treatment depends on its efficacy and side effects. With regard to acute drug therapy, group studies do not suggest that ergot derivatives and sumatriptan are superior to simple analgesics and anti-inflammatory drugs, particularly if a prokinetic agent is added. These new substances are indicated for severe attacks refractory to more conventional therapy. Chronic drug abuse may induce drug-induced or rebound headaches. As regards long-term prophylaxis, group studies suggest that calcium antagonists and 5-HT-influencing drugs are superior concerning attacks frequency to beta-blocking agents, but involve very frequent side effects (weight gain and somnolence). Interesting preliminary results have also been reported with valproate and enalapril, which will confirmation by controlled studies. Finally, the choice of drug must take into account the patient's comorbidities (cardiovascular diseases, asthma, diabetes etc).

Acetaminophen↗

Percutaneous endoscopic gastrostomy in neurological rehabilitation: a report of six cases.

PURPOSE: This study reports the cases of six patients with severe chronic neurological disability and swallowing difficulties due to traumatic brain injury (TBI), anoxia and multiple sclerosis (MS). METHOD: The patients required nutritional supplement through percutaneous endoscopic gastrostomy (PEG). RESULTS: Their clinical follow-up showed a decrease of intercurrent medical complications, especially pressure sores. In addition, an improvement of oropharyngeal function was observed in some patients, also accompanied by slightly better basic psychomotor functions such as vigilance, sustained attention and tone or motor control. However, not every patient did improve with this procedure. The two MS patients benefited most, while the improvement was less homogenous in the three TBI patients. CONCLUSIONS: The advantages of PEG over nasogastric tube on oropharyngeal function can be related to the absence of pharyngeal irritation and its role in overall recovery could be due to an increase in social activities, a control of infections, a better rehabilitation schedule and a long-term effect on brain function due to better nutritional support.

Adult↗

Random motor generation in a finger tapping task: influence of spatial contingency and of cortical and subcortical hemispheric brain lesions.

OBJECTIVE: To test the hypothesis that, during random motor generation, the spatial contingencies inherent to the task would induce additional preferences in normal subjects, shifting their performances farther from randomness. By contrast, perceptual or executive dysfunction could alter these task related biases in patients with brain damage. METHODS: Two groups of patients, with right and left focal brain lesions, as well as 25 right handed subjects matched for age and handedness were asked to execute a random choice motor task--namely, to generate a random series of 180 button presses from a set of 10 keys placed vertically in front of them. RESULTS: In the control group, as in the left brain lesion group, motor generation was subject to deviations from theoretical expected randomness, similar to those when numbers are generated mentally, as immediate repetitions (successive presses on the same key) are avoided. However, the distribution of button presses was also contingent on the topographic disposition of the keys: the central keys were chosen more often than those placed at extreme positions. Small distances were favoured, particularly with the left hand. These patterns were influenced by implicit strategies and task related contingencies. By contrast, right brain lesion patients with frontal involvement tended to show a more square distribution of key presses--that is, the number of key presses tended to be more equally distributed. The strategies were also altered by brain lesions: the number of immediate repetitions was more frequent when the lesion involved the right frontal areas yielding a random generation nearer to expected theoretical randomness. The frequency of adjacent key presses was increased by right anterior and left posterior cortical as well as by right subcortical lesions, but decreased by left subcortical lesions. CONCLUSIONS: Depending on the side of the lesion and the degree of cortical-subcortical involvement, the deficits take on a different aspect and direct repetions and adjacent key presses have different patterns of alterations. Motor random generation is therefore a complex task which seems to necessitate the participation of numerous cerebral structures, among which those situated in the right frontal, left posterior, and subcortical regions have a predominant role.

Adult↗

[Sequelae of severe craniocerebral injuries. An epidemiological study in the Canton of St. Gallen].

Severe head injuries often lead to serious medical and socioeconomic sequelae. The incidence rate indicated in other studies shows a wide variation due to differences in selection criteria. Based upon an unselected population, the incidence of severe head injury was calculated and the surviving patients were interviewed and clinically examined 3 years after the accident in order to describe the course, rehabilitation and psychosocial sequelae after severe head injury. Retrospectively we collected 80 patients living in the canton of St. Gallen who had a severe head injury requiring hospitalization in 1987, indicating an incidence of 20 per 100,000 inhabitants. 22 (28%) of these patients died as a consequence of the head trauma. The best predictor was the Glasgow coma score at admission, which showed a highly significant direct correlation with survival rate. Regarding the degree of impairment of survivors the duration of posttraumatic amnesia was the best predictive parameter. Of the 45 patients controlled 3 years after the head trauma only 11% were severely impaired in daily activities. 79% of the patients who were gainfully employed before the accident were working full- or at least part-time. However, only 3 patients (7%) were absolutely free of symptoms. Most patients suffered from cognitive and emotional deficits. Based on an estimated incidence for minor head trauma of 174 per 100,000 inhabitants, a total annual incidence for all head traumas of 194 per 100,000 inhabitants is calculated, with severe head injury representing about 1/9 of all head injuries.

Adolescent↗

Pharmacology of the vestibular hair cell-afferent fiber synapse in the frog.

The isolated, intact, membranous labyrinth of the frog (Rana temporaria) has been investigated electrophysiologically in vitro to determine the nature of the transmitter substance at the synapse between the vestibular hair cells and afferent fibers. Spontaneous synaptic activity can be monitored with intra-axonal recordings from the afferents. Increased K+ in the bath results in an increase in frequency of presynaptic release, as indicated by an increased frequency of spontaneous synaptic potentials. Adding Mg2+ and lowering Ca2+ results in a decrease in synaptic potential frequency (often to zero) with no change in their mean amplitude, indicating pre-synaptic blockade. Extracellular recordings from individual vestibular afferents indicate that bath-applied glutamate and related acidic amino acids consistently increase the firing rates of these afferents in a dose-dependent manner with no evidence of desensitization. In the presence of presynaptic blockade (high Mg2+/low Ca2+), bath application of glutamate and its agonists results in a reversible depolarization of vestibular afferents, suggesting a postsynaptic action of these substances. 2-Amino-5-phosphonovaleric acid, kynurenic acid, and other acidic amino acid antagonists reversibly decrease the amplitudes of spontaneously occurring synaptic potentials without affecting their frequency, indicating subsynaptic blockade. These antagonists also block the postsynaptic depolarizations due to glutamate and its agonists. GABA and its agonists and antagonists have no consistent effect upon afferent activity. These findings suggest that glutamate, aspartate, or a related compound is the transmitter at this synapse. However, the antagonists used, or the receptors themselves, are not selective enough to discriminate adequately between the agonists. Therefore, which of these glutamate agonists are actually involved in synaptic transmission remains to be determined.

Afferent Pathways↗

Respiratory function in chronic hemiplegia.

Dynamic spirometry was examined in 23 non-smoking hemiplegic patients after the acute phase. The decrease of slow inspiratory forced capacity is related to motor impairment and does not vary with time. The forced inspiratory and expiratory vital capacities are similar to the slow inspiratory vital capacity in the first 6 months of the disease, but significantly decrease later independent of the motor impairment. The peak expiratory flow is highly variable but is clearly decreased, and is related to motor impairment. These results point to a restrictive respiratory syndrome due to mechanical limitation of thorax excursions caused by weakness, hypotonicity, and incoordination of the trunk musculature. The importance of long-term physiotherapy of the trunk is emphasized.

Adult↗

Severe traumatic brain injury--epidemiology and outcome after 3 years.

In 1987 80 patients living in the region of St Gallen, Switzerland, suffered from head injury with neuroradiologically visible intracranial lesions (annual incidence 20/100,000). One-quarter died during the first month after injury, and six others during the following 3 years. All except three of the 45 survivors interviewed and examined after 3 years had symptoms and functional impairment related to injury: neuropsychological (78%), behavioural (58%), neurological (53%), and related to bone or soft tissue trauma (36%). Half of the patients suffered from headache. Although these impairments caused little disability--only 5% of the patients had a Glasgow Outcome Score of 2 or 3--handicap in social life was reported in half of them and only 13 of 29 working before the accident were able to resume their former work. The consequences for long-term management of these patients are discussed.

Adolescent↗

Four case reports illustrating the contribution of intensive cognitive rehabilitation in patients neuropsychologically handicapped as a result of brain damage.

The authors describe the principles and functioning of a 7-week course of interdisciplinary treatment for small groups of patients with cognitive and behavioral difficulties resulting from brain damage. The programme is intended for patients with less severe physical disability. It outlines a programme of individual, practically oriented workshops and of more theoretical group sessions working on cognitive and communications handicaps. The work is based on conceptual explanations, coping strategies and training techniques. The neurological and neuropsychological consequences of four subjects accepted on such a programme are presented, as well as some of the principles of treatment used for these patients. The efficacy of such programmes is discussed, given the classical post-traumatic picture of brain-injured patients. The programme consists of 1 week of evaluation and 6 weeks of therapeutic sessions.

Adult↗