Influence of Experimental Warming on the Rate and Duration of Fruit Growth and Oil Accumulation in Young Olive Trees (cvs. Arbequina, Coratina).

Olive tree cultivation in new warmer areas and climate change have increased the global interest in understanding how air temperature affects both fruit growth and oil accumulation. The aims of this study were to evaluate the rate and duration of fruit growth and oil accumulation in response to experimental warming (+3) in a semiarid region of Argentina; and assess how warming affected fatty acid composition. Young, potted olive trees (cvs. Arbequina, Coratina) were warmed (T+) or maintained near ambient temperature (T0) inside open top chambers in the field during oil accumulation in 2014-2015 or 2015-2016 using different trees in each season. Warming reduced the rate of both fruit growth and oil accumulation in T+ compared to T0 in both cultivars. These rate reductions under T+ led to large decreases in final fruit dry weight and oil concentration. In contrast, the durations (i.e., days) of fruit growth and oil accumulation were most often not affected. Cultivar x temperature interactions were observed in 2014-2015 with warming decreasing oleic acid and increasing linoleic acid in cv. Arbequina, while cv. Coratina showed no response to warming. However, no interactions were found in 2015-2016. Studying how fruit growth and oil accumulation respond to adaptation strategies against increasing air temperatures should be a priority in both young and mature olive trees of numerous cultivars given crop expansion to new regions and future climate scenarios.

Influence of environmental growth temperature on tocopherol and sterol oil concentrations in olive fruit.

BACKGROUND: Tocopherols and sterols are minor components of virgin olive oils that contribute to oil quality. Based on observations at different geographical locations, it has been suggested that environmental temperature during fruit growth affects tocopherol and sterol oil concentrations in olive fruit. However, controlled experiments have not been conducted to directly assess their responses to temperature. In this study, a manipulative experiment using open-top chambers (OTCs) was performed in the field to evaluate the responses of these oil components to a moderate air temperature increase during oil accumulation in young trees of two olive cultivars (Arbequina, Coratina). The two temperature levels in the OTCs were a control about 1 °C above ambient temperature (T0) and a heated treatment (T+) with a target temperature of 4 °C above T0. RESULTS: Total tocopherol and sterol oil concentrations in olive fruit were generally higher in the T+ temperature treatment than in the control at the end of the oil accumulation period. The increase in total tocopherols in T+ appeared to be related to a decrease in fruit oil concentration with heating. Individual sterols showed both significant increases and decreases due to T+, and some differences in response occurred between the two cultivars. CONCLUSION: These findings provide evidence that growth temperature affects tocopherol and sterol oil concentrations in olive fruit at the end of the oil accumulation period. Cultivars should be carefully chosen for new olive-growing regions, and the results could be relevant for global warming scenarios in existing growing regions. © 2021 Society of Chemical Industry.

Effects of prolonged elevated temperature on leaf gas exchange and other leaf traits in young olive trees.

Despite the economic importance of long-lived crop species in the Mediterranean Basin and their expansion to new warmer regions, their potential responses to prolonged temperature increases have not been adequately addressed. The objectives of this study were to: (i) assess leaf gas exchange responses to prolonged elevated temperature in young olive trees; (ii) evaluate some additional leaf traits such as stomatal density and size under these same conditions; and (iii) determine whether photosynthetic acclimation to temperature was apparent. A field experiment with two temperature levels was conducted using well-irrigated, potted olive trees (cvs. Arbequina, Coratina) grown in open-top chambers during the summer and early fall in two growing seasons. The temperature levels were a near-ambient control (T0) and a heated (T+) treatment (+4 °C). Maximum photosynthetic rate (Amax), stomatal conductance (gs), transpiration (E) and chlorophyll fluorescence were measured. Stomatal size and density and trichome density were also determined. The Amax, gs and chlorophyll fluorescence were little affected by heating. However, leaf E was higher at T+ than T0 in the summer in both seasons due in large part to the moderate increase in vapor pressure deficit that accompanied heating, and consequently water-use efficiency was reduced in heated leaves. When reciprocal temperature measurements were conducted in mid-summer of the second season, Amax values of T0 and T+ leaves were higher under the temperature level at which they grew than when measured at the other temperature level, which suggests some thermal acclimation. Stomatal size and density were greater in T+ than in T0 grown leaves in some cases, which was consistent with a greater E in T+ leaves when measured at both temperature levels. These results suggest that acclimation to long-term changes in temperature must be carefully considered to help determine how olive trees will be influenced by global warming.

Olive Cultivation in the Southern Hemisphere: Flowering, Water Requirements and Oil Quality Responses to New Crop Environments.

Olive (Olea europaea L.) is a crop well adapted to the environmental conditions prevailing in the Mediterranean Basin. Nevertheless, the increasing international demand for olive oil and table olives in the last two decades has led to expansion of olive cultivation in some countries of the southern hemisphere, notably in Argentina, Chile, Perú and Australia. While the percentage of world production represented by these countries is still low, many of the new production regions do not have typical Mediterranean climates, and some are located at subtropical latitudes where there is relatively little information about crop function. Thus, the primary objective of this review was to assess recently published scientific literature on olive cultivation in these new crop environments. The review focuses on three main aspects: (a) chilling requirements for flowering, (b) water requirements and irrigation management, and (c) environmental effects on fruit oil concentration and quality. In many arid and semiarid regions of South America, temperatures are high and rainfall is low in the winter and early spring months compared to conditions in much of the Mediterranean Basin. High temperatures have often been found to have detrimental effects on olive flowering in many olive cultivars that have been introduced to South America, and a better understanding of chilling requirements is needed. Lack of rainfall in the winter and spring also has resulted in an urgent need to evaluate water requirements from the flower differentiation period in the winter to early fruit bearing. Additionally, in some olive growing areas of South America and Australia, high early season temperatures affect the timing of phenological events such that the onset of oil synthesis occurs sooner than in the Mediterranean Basin with most oil accumulation taking place in the summer when temperatures are very high. Increasing mean daily temperatures have been demonstrated to decrease fruit oil concentration (%) and negatively affect some aspects of oil quality based on both correlative field studies and manipulative experiments. From a practical standpoint, current findings could be used as approximate tools to determine whether the temperature conditions in a proposed new growing region are appropriate for achieving sustainable oil productivity and quality.

Treatment of dystonia in extensor hallucis longus and digitorum muscles with neurotomy of the branches of the deep fibular nerve: Preliminary results.

INTRODUCTION: Dystonia in extensor hallucis and/or digitorum muscles can be observed in pyramidal and extrapyramidal lesions and results in pain in these toes, spontaneous or when walking, problems and discomfort when putting on shoes and socks, and cutaneous lesions on the toes. The objective of this study was to assess the efficacy and safety of deep fibular nerve neurotomy for the extensor hallucis longus (EHL) and/or the extensor digitorum longus (EDL) branches in the treatment of extension dystonia of the hallux and/or other toes. PATIENTS AND METHODS: A deep fibular nerve neurotomy was performed in 20 patients (n=19 for the EHL, n=6 for the EDL). We retrospectively analyzed the treatment's efficacy and safety and assessed the patients' self-reported improvement and overall treatment satisfaction. RESULTS: Dystonia totally disappeared in 15 cases (75%); it persisted at a minimal level in the other patients. The patients reported a decrease in pain (P<0.01) and fewer difficulties putting on shoes and socks (P<0.001) and had a high median level of satisfaction (8.5/10). Adverse effects were rare and transient. The identification of the nerve branches was sometimes difficult. DISCUSSION: Deep fibular nerve neurotomy for the EHL and/or EDL branches seems to be an effective treatment for extension dystonia of the hallux and/or other toes and its consequences for the adult neurological patient. However, these encouraging preliminary results should be confirmed by prospective, longer-term studies.

The Cognitive Assessment scale for Stroke Patients (CASP) vs. MMSE and MoCA in non-aphasic hemispheric stroke patients.

INTRODUCTION: CASP specifically assesses post-stroke cognitive impairments. Its items are visual and as such can be administered to patients with severe expressive aphasia. We have previously shown that the CASP was more suitable than the Mini Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA) in aphasic patients. Our objective was to compare the above scales in non-aphasic stroke patients, and assess to what extent the solely visual items of the CASP were problematic in cases of neurovisual impairments. METHODS: Fifty non-aphasic patients admitted to Physical Medicine and Rehabilitation (PM&R) units after a recent left- or right-hemisphere stroke were evaluated with the CASP, MMSE and MoCA. We compared these three scales in terms of feasibility, concordance, and influence of neurovisual impairments on the total score. RESULTS: Twenty-nine men and 21 women were included (mean age 63 ± 14). For three patients, the MoCa was impossible to administer. It took significantly less time to administer the CASP (10 ± 5 min) than the MoCA (11 ± 5 min, P=0.02), yet it still took more time than MMSE administration (7 ± 3 min, P<10(-6)). Neurovisual impairments affected equally the total scores of the three tests. Concordance between these scores was poor and only the CASP could specifically assess unilateral spatial neglect. CONCLUSION: The sole visual format of the CASP scale seems suitable for administration in post-stroke patients.

Feasibility of the cognitive assessment scale for stroke patients (CASP) vs. MMSE and MoCA in aphasic left hemispheric stroke patients.

INTRODUCTION: Post-stroke aphasia makes it difficult to assess cognitive deficiencies. We thus developed the CASP, which can be administered without using language. Our objective was to compare the feasibility of the CASP, the Mini Mental State Examination (MMSE) and the Montreal Cognitive Assessment (MoCA) in aphasic stroke patients. MATERIAL AND METHODS: All aphasic patients consecutively admitted to seven French rehabilitation units during a 4-month period after a recent first left hemispheric stroke were assessed with CASP, MMSE and MoCA. We determined the proportion of patients in whom it was impossible to administer at least one item from these 3 scales, and compared their administration times. RESULTS: Forty-four patients were included (age 64±15, 26 males). The CASP was impossible to administer in eight of them (18%), compared with 16 for the MMSE (36%, P=0.05) and 13 for the MoCA (30%, P=0.21, NS). It was possible to administer the CASP in all of the patients with expressive aphasia, whereas the MMSE and the MoCA could not be administered. Administration times were longer for the CASP (13±4min) than for the MMSE (8±3min, P<10(-6)) and the MoCA (11±5min, P=0.23, NS). CONCLUSION: The CASP is more feasible than the MMSE and the MoCA in aphasic stroke patients.

Integration of visual and haptic informations in the perception of the vertical in young and old healthy adults and right brain-damaged patients.

OBJECTIVE: Multimodal perception raises the issue of sensory integration. The aim of this study is to assess whether the visuo-haptic subjective vertical could be predicted from the visual and haptic unimodal performances, according to a Bayesian model, which optimizes the reliability of the multimodal estimate. The limits of the model were assessed by evaluating the impact of aging, cerebral damage and spatial deficits. METHOD: Young and older healthy participants, as well as patients with a right hemisphere lesion, suffering from spatial neglect or not, had to align a rod with the gravitational vertical in the visual, haptic and visuo-haptic modalities. RESULTS: Visuo-haptic subjective vertical was correctly predicted by the model in healthy participants, as well as in patients in spite of different performances. An anticlockwise deviation of the subjective vertical was observed in the neglect group whatever the experimental conditions. By contrast, no deviation was observed in both non-neglect and healthy groups, for the visual and the visuo-haptic modalities. Nevertheless, the haptic subjective vertical was deviated, anticlockwise in the non-neglect patients and older healthy adults, and clockwise in the young healthy adults. Moreover, the variance was the smallest in the bimodal condition. CONCLUSION: The integration of visual and haptic signals appeared to obey a Bayesian model optimizing the reliability of the multimodal estimate. This holds true despite of aging, brain damage or visuospatial disorders. Regarding the perception of the vertical, multisensory integration does not seem thus to depend only on right posterior cortical areas.

Body representations and brain damage.

We review changes in body representation in patients with brain hemisphere damage and discuss their relationship with impaired limb movements in peripersonal space, navigation between objects/obstacles and control of the body's general posture and balance. The egocentric representation of the body's median sagittal axis (considered as the main zone around which movements are anchored) has been studied in most detail. This reference is distorted in patients with spatial neglect and involves a combination of ipsilesional translation and contralesional tilt. There are clear links with the patients' difficulties in egocentric tasks, activities of daily living and postural control. In both healthy subjects and patients, this reference axis can be modulated by somaesthetic, vestibular and visual stimulations; these phenomena have been used in rehabilitation programmes to reduce disease-induced deviations. A few studies have analyzed other lateral body reference (at the shoulders, in particular). These references were found to be more severely affected than the body midline (notably on the contralesional side). The severity of the distortion was related to the presence of lesions that mainly affected the parietal, somatosensory and multimodal association cortex (notably around the intraparietal sulcus) and, to a lesser extent, the middle temporal and frontal dorsolateral premotor cortex. These convergent results suggested that patients (notably those with neglect) have a complex distortion of the body schema and the perceptive representations of the body, that does not simply correspond to poor awareness of the contralateral hemicorpus.

Gesture comprehension, knowledge and production in Alzheimer's disease.

BACKGROUND AND PURPOSE: Although apraxia is a typical consequence of Alzheimer's disease (AD), the profile of apraxic impairments is still subject to debate. Here, we analysed apraxia components in patients with AD with mild-to-moderate or moderately severe dementia. METHODS: Thirty-one patients were included. We first evaluated simple gestures, that is, the imitation of finger and hand configurations, symbolic gestures (recognition, production on verbal command and imitation), pantomimes (recognition, production on verbal command, imitation and production with the object), general knowledge and complex gestures (tool-object association, function-tool association, production of complex actions and knowledge about action sequences). Tests for dementia (Mini Mental State Examination and the Dementia Rating Scale), language disorders, visual agnosia and executive function were also administered. RESULTS: Compared with controls, patients showed significant difficulties (P ≤ 0.01) in subtests relating to simple gestures (except for the recognition and imitation of symbolic gestures). General knowledge about tools, objects and action sequences was less severely impaired. Performance was frequently correlated with the severity of dementia. Multiple-case analyses revealed that (i) the frequency of apraxia depended on the definition used, (ii) ideomotor apraxia was more frequent than ideational apraxia, (iii) conceptual difficulties were slightly more frequent than production difficulties in the early stage of AD and (iv) difficulties in gesture recognition were frequent (especially for pantomimes). CONCLUSION: Patients with AD can clearly show gesture apraxia from the mild-moderate stage of dementia onwards. Recognition and imitation disorders are relatively frequent (especially for pantomimes). We did not find conceptual difficulties to be the main problem in early-stage AD.

Hemianopia and neglect influence on straight-ahead perception.

In spatial neglect, the pathological ipsilesional deviation of the subjective straight ahead (SSA) received both 'translational' and 'rotational' interpretations. Furthermore, hemianopia per se could also influence straight-ahead (SA) perception. Here, we aimed at disentangling the relative effects of neglect and hemianopia on the SSA by using a method analyzing translation and rotation in parallel. We included patients with a right hemisphere stroke. Ten had neglect and hemianopia, 6 neglect only, 3 hemianopia only, and 12 neither one nor the other. 15 were controls. Participants had to adjust a bar, movable in translation and rotation, SA of the navel, in darkness. Patients with spatial neglect showed systematic rightward translation, greater when hemianoptic. The rotation component appeared more variable and was influenced by the presence of a visual field defect, as most of the patients with hemianopia showed an anticlockwise rotation and most of the patients without hemianopia a clockwise rotation. Non-neglect patients and control subjects demonstrated a fair performance level. In conclusion, both neglect and hemianopia resulted in a translation error of the SSA to the ipsilesional side. In neglect patients, additional hemianopia resulted in a counterclockwise rotation. Furthermore, rotation and translation errors appeared dissociated, suggesting a different coding of these dimensions by the right posterior hemisphere.

Loss of the Parkinson's disease-linked gene DJ-1 perturbs mitochondrial dynamics.

Growing evidence highlights a role for mitochondrial dysfunction and oxidative stress as underlying contributors to Parkinson's disease (PD) pathogenesis. DJ-1 (PARK7) is a recently identified recessive familial PD gene. Its loss leads to increased susceptibility of neurons to oxidative stress and death. However, its mechanism of action is not fully understood. Presently, we report that DJ-1 deficiency in cell lines, cultured neurons, mouse brain and lymphoblast cells derived from DJ-1 patients display aberrant mitochondrial morphology. We also show that these DJ-1-dependent mitochondrial defects contribute to oxidative stress-induced sensitivity to cell death since reversal of this fragmented mitochondrial phenotype abrogates neuronal cell death. Reactive oxygen species (ROS) appear to play a critical role in the observed defects, as ROS scavengers rescue the phenotype and mitochondria isolated from DJ-1 deficient animals produce more ROS compared with control. Importantly, the aberrant mitochondrial phenotype can be rescued by the expression of Pink1 and Parkin, two PD-linked genes involved in regulating mitochondrial dynamics and quality control. Finally, we show that DJ-1 deficiency leads to altered autophagy in murine and human cells. Our findings define a mechanism by which the DJ-1-dependent mitochondrial defects contribute to the increased sensitivity to oxidative stress-induced cell death that has been previously reported.

An analysis of communication in conversation after severe traumatic brain injury.

BACKGROUND AND OBJECTIVE: Communication disorders have been reported following severe traumatic brain injury. However, we have little information about patient behaviour during dyadic interaction. Here, we analyzed conversation at the rehabilitation and chronic phase post traumatic brain injury (TBI), to define the main mechanisms of verbal and non-verbal communication disorders and relationship with other cognitive difficulties. METHODS: Sixteen patients were evaluated at the rehabilitation phase (2-12 months) and 18 at the chronic phase (after 2 years) following severe TBI. They were compared with equivalent groups of matching (gender, age, education level) control subjects. We used the Lille Communication Test, which comprises three parts: participation to communication (greeting, attention, engagement), verbal communication (verbal comprehension, speech outflow, intelligibility, word production, syntax, verbal pragmatics, verbal feedback) and non-verbal communication (understanding gestures, affective expressivity, producing gestures, pragmatics, non-verbal feedback). We also investigated executive functions (Stroop test, trail-making test, categorical evocation), language (Montreal-Toulouse protocol) and behaviour (Neurobehavioural Rating Scale). Verbal communication disorders were relatively equivalent at the rehabilitation and chronic phases. RESULTS: Patients were impaired (P < or = 0.01) in their participation to communication, especially in greeting behaviour. Verbal communication was mostly affected by difficulties in producing fluent and intelligible language and using pragmatics (responding to open questions, presenting new information and introducing new themes, organizing discourse and adapting to interlocutor knowledge). Non-verbal communication was impaired by difficulties in using pragmatics (mostly adapted prosody). Participation and verbal communication correlated with the executive functions, language and behavioural assessment. CONCLUSIONS: Disorders of social communication justify systematic assessment in patients with TBI.

Value and efficacy of early supported discharge from stroke units.

OBJECTIVES: The goal of early supported discharge (ESD) is to reduce the duration of in-patient care in stroke units (SUs) and to optimize the management of pre- and post-discharge rehabilitation. Here, we report on and discuss ESD's effects on various outcome parameters in stroke patients. METHODS: Analysis of randomized, controlled studies and meta-analyses identified in the Medline and Cochrane databases. RESULTS: ESD interventions have been evaluated in more than 10 studies. Most of the included patients had suffered from mild or moderate strokes. Meta-analyses have shown that when compared with standard care, ESD has a positive effect on the risk of death or institutionalisation, death or dependence and participation in instrumental activities of daily living (iADL). In-patient hospitalization in the SU and the overall cost of care were significantly lower. Individual studies showed variability in the inclusion criteria, type of care, comparisons performed and conclusions drawn. ESD's superiority in terms of the risk of death or dependency was mainly reported in a Norwegian study and that in terms of iADL was reported in a Swedish study. There was no specific effect on functional impairment and personal ADL (pADL). DISCUSSION: This technique reduces the length of the in-patient stay and the overall cost of care while lowering the risk of death or institutionalisation and promoting participation in iADL. However, studies on this topic are heterogeneous.

Evidence of persisting cognitive impairment in a case series of patients with locked-in syndrome.

OBJECTIVE: Previous research on cognition and locked-in syndrome (LIS) is limited to single case reports, and usually reported normality of performance. Here, cognitive disorders in a group of LIS patients are investigated, using a specific test relying only on a yes/no response indicated by eye movements or verbally. METHODS: Nine patients with LIS resulting from brainstem stroke were compared with seven patients with frontal or frontotemporal lesions and 16 matching normal control subjects. The test comprised 19 subtests of perception (visual and auditory recognition), oral comprehension (identity, words and sentences), written comprehension (words and sentences), orientation (in time and place), immediate and delayed memories (verbal and visuo-spatial information), calculation and problem solving, and analysis of verbal logic. RESULTS: LIS patients showed significant difficulties in auditory recognition (associative level), oral comprehension of complex sentences, delayed visuospatial memory, mental calculation and problem solving. Patients with hemispheric lesions were more severely impaired. Single case analysis revealed that four LIS patients showed cognitive disorders in at least three subtests. These disorders were not related to a specific localisation of lesions. CONCLUSIONS: Moderate and selective cognitive disorders can be observed in LIS patients. Systematic assessment is needed, because of their possible consequences for communication and rehabilitation protocols.

[The adolescent to adulthood transition of persons with traumatic-brain injury: the physical-medicine point of view]. / La transition adolescent à adulte du traumatisme crânien: le point de vue de la médecine physique.

Traumatic-brain injury (TBI) is relatively frequent and can involve children and adolescents; it causes not only physical but also important neuropsychological and behavioral problems that can impair familial, social, and professional reintegration. The affected person requires long-term follow-up of medical, psychological, and social problems. The transition from childhood to adulthood, which can cause problems related to the lack of organization and training of specialized TBI medicosocial teams and structures in adult care for both the family, which is reluctant to change, and the patient, who often shows anosognosia, therefore requires organized coordination between pediatric and adult-care teams. This transition must be prepared early and in collaboration with the patient and his family. It first concerns physicians, both pediatric and adult specialists, who need to develop closer collaboration and cooperation. However, the patient should remain the main actor, because the objective is to transfer diversified healthcare, which depends on the TBI patient's individual problems. This relates to medical treatments and, more generally, the life project, which should not be disturbed by divergent practices. The main measures enabling harmonious transfer are training, establishment of specific procedures, and, most particularly, networking.

Comparison of botulinum toxin injection and neurotomy in patients with distal lower limb spasticity.

BACKGROUND AND PURPOSE: We compared the efficacy of botulinum toxin injection (BTI) and tibial nerve neurotomy (TNN) in an open-label study of 34 post-stroke hemiplegic patients with distal lower limb deformation. METHODS: The dose of BT was 300 U (Botox). TNN was performed with a 6-12 month delay on the motor branches of the tibial nerve. Muscles to be treated were selected according to the distal deformity (equinus, varus and clawing toes). Patients were assessed following each treatment for spasticity, motor control, range of movements, balance, gait and the Rivermead Motor Assessment. RESULTS: TNN (M3, M6 and Y1) resulted in a more significant effect than BTI (D15, M2 and M5) on most of the measures: ankle plantar flexor spasticity, range of movement in dorsiflexion and eversion, foot position in upright situation, Functional Ambulation Categories (barefoot), RMA, gait velocity (comfortable condition), subjective benefit and use of walking aids. Patients treated for tibialis posterior or flexor digitorum longus spasticity often complained of subjective sensory disorders at the plantar sole over a period of 4-6 weeks. CONCLUSION: In conclusion, TNN is more effective than BTI on most of the functional parameters. The interest of BTI lies in the preliminary testing of the efficacy of a technique for reducing spasticity on lower limb function.

Reducing rightward bias of subjective straight ahead in neglect patients by changes in body orientation.

BACKGROUND: The subjective straight ahead (SSA), a measure of the representation of body orientation, has been shown to be shifted to the lesion side in neglect patients, and to be influenced by stimulation of sensory systems involved in postural control. METHOD: This study investigates the influence of changing body orientation in the sagittal plane on the SSA in 21 patients with a right hemispheric lesion, of whom 12 had neglect, in comparison with six healthy control subjects. In order to quantify both horizontal components of SSA error (ie, yaw rotation and lateral shift), the study used a method requiring the alignment of a luminous rod with SSA. RESULTS: Neglect patients showed a significant rightward shift in the sitting position, which was greatly reduced in the supine position. No shift occurred in patients without neglect or in controls. Yaw rotation did not reach significance in any group. CONCLUSION: The data showed that the body centred frame of reference, mostly translated in neglect, is strongly improved in the supine position. Changing body orientation seems to be a convenient tool to correct the representation of body midline.

[The risk-benefit of high doses of botulinum toxin injections for muscle spasticity ]. / Place des doses élevées dans les injections de toxine botulique.

OBJECTIVE: To bring general elements of reflection on the use of the high doses of botulinum toxin in spastic children and adults. MATERIAL AND METHODS: Review of the literature on the high doses and the benefit-risk associated with botulinum toxin injections. RESULTS: The medical literature exclusively relates to the use of the high doses in children and adolescents. Comparative work with conventional doses suggests a relative interest, but with a risk of increased side effects. Several articles report on treatments with high and even very high doses in series of patient, with a documented effectiveness. But their justification remains partial and the study of the possible side effects is limited. Reflections are brought to contribute to the debate on the use of high doses, taking into account the local physiological effect of botulinum toxin, the risk of regional and general diffusion, the need for a progressive strategy, the variability of effects, the cost of the treatment and the need for obtaining an informed consent of the patient and of significant others. CONCLUSION: The use of high doses of botulinum toxin increases progressively, but must remain very careful.