[Results and compliance of transcutaneous tibial nerve stimulation on overactive bladder syndrome in patients with Parkinson's disease. Retrospective Study.] / Résultats et observance de la stimulation transcutanée du nerf tibial dans l'hyperactivité vésicale de la maladie de Parkinson idiopathique. Étude rétrospective.

PURPOSE: To investigate efficiency and tolerance of transcutaneous tibial nerve stimulation (TNS) in the overactive bladder syndrome in patients with Parkinson's disease (PD), and to identify predictive factors for compliance. METHODS: We conducted a retrospective monocentric study with a cohort of 17 patients with PD who have used TNS for an overactive bladder syndrome. The efficiency of the treatment was evaluated on the clinical improvement felt (rated out of ten). Patients were classified as « adopters ¼ if they continued using TNS for at least one year after beginning the treatment or as « non adopters ¼ if they stopped. Patients characteristics were evaluated for their predictive value for compliance with TNS. RESULTS: Out of 17 patients, there were 9 women and 8 men, median age 66 years (55-77), median history for Parkinson's disease 8 years (1-22) and for urinary symptoms 3 years (1-10). Subjective efficiency was seen in 10 patients (59%), on nocturia and/or urinary incontinence for 9 patients (mean efficiency 5.75/10 and median efficiency 6.5/10). Three patients found TNS not effective, and four patients didn't use it long enough to evaluate. Two patients had side effects and stopped the TNS (feeling of electricity and restless leg syndrome). 7 patients were classified as « adopters ¼ and 10 patients as « non adopters ¼ after one year. Most evaluated characteristics proved not to be of predictive value for compliance with TNS except nocturia and pollakiuria (P=0.03 and P=0.05). CONCLUSION: Our study seems to reveal TNS is particularly effective on nocturia and urge. Moreover, nocturia and pollakiuria appear to be predictive factors for SNT compliance. Nocturia could be a prominent symptom in SNT's prescription. But studies with more patients should be conducted for obtain better patient selection in TNS. LEVEL OF EVIDENCE: IV.

Could motor imagery be effective in upper limb rehabilitation of individuals with spinal cord injury? A case study.

STUDY DESIGN: A case study. OBJECTIVE: The aim was to investigate whether motor imagery (MI) could be successfully incorporated into conventional therapy among individuals with spinal cord injury (SCI) to improve upper limb (UL) function. SETTING: The Physical Medicine and Rehabilitation Unit at the Henry Gabrielle Hospital in Lyon, France. METHODS: The participant was an individual with a complete C6 SCI. MI content was focused on functional UL movements, to improve hand transport to reach out and grasp with tenodesis. The participant was tested before and after 15 MI training sessions (45 min each, three times a week during 5 consecutive weeks). MI ability and program compliance were used as indicators of feasibility. The Minnesota and Box and Blocks tests, as well as movement time and hand trajectory during targeted movements were the dependent variables, evaluating motor performance before and after MI training. RESULTS: The participant's ability to generate MI was checked and compliance with the rehabilitation program was confirmed. The time needed to complete the Minnesota test decreased by 1 min 25 s. The Box and Blocks score was improved by three units after MI program. Decreased movement time and enhanced hand trajectory smoothness were still observed 3 months later, despite a slight decrease in performance. CONCLUSIONS: This study supports the feasibility for introducing MI in conventional therapy. Further studies should confirm the potential role of MI in motor recovery with a larger sample.

Facial macrosomatognosia and pain in a case of Wallenberg's syndrome: selective effects of vestibular and transcutaneous stimulations.

Macro- and micro-somatognosia refer to rare disorders of the cerebral representation of the body whereby patients perceive body parts as disproportionately large or small. Here we report the experimental study of a patient who, following a left lateral medullary stroke (Wallenberg's syndrome, including vestibular deficits) complained of a persistent somatosensory illusory sensation of swelling, confined to the left side of his face (i.e., left macrosomatognosia). This hemifacial somatosensory distortion was associated with a left facial anesthesia, and a neuropathic pain affecting the three branches of the left trigeminal nerve. In this study, we first document quantitatively the patient's somatosensory illusion by using a somatosensory-to-visual matching task in which the patient modified the picture of his own face to fit his left-sided somatosensory misperception. The patient's performance revealed that macrosomatognosia was confined to the second branch of the left trigeminal nerve. Perception of the size of visual objects was comparatively preserved. Second, we investigated the effects of two peripheral stimulations, which may affect the spatial component of somatosensory deficits (caloric vestibular stimulation, CVS; transcutaneous electrical nervous stimulation, TENS) and pain (TENS). Left CVS abolished the facial somatosensory illusion, for about 30min, but had no effect on the left facial pain. Conversely, left TENS substantially reduced the neuropathic pain during stimulation, but had no effect on macrosomatognosia, indicating a double dissociation between the two disorders. These results reveal that facial macrosomatognosia may be regarded as a high-order deficit of somatosensory perception of the shape and volume of the face, which fits the definition of 'hyperschematia' (i.e., when the body takes up too much room) originally proposed by Bonnier (1905). Our data also indicate that CVS may favor the restoration of the conscious representation of the shape and size of the face. Overall, these findings lend support to the view that afferent inputs from the vestibular system can affect in a specific fashion the activity of cerebral structures involved in the building up and updating of the topological description of body parts.

Effect of prism adaptation on left dichotic listening deficit in neglect patients: glasses to hear better?

Unilateral neglect is a disabling syndrome frequently observed following right hemisphere brain damage. Symptoms range from visuo-motor impairments through to deficient visuo-spatial imagery, but impairment can also affect the auditory modality. A short period of adaptation to a rightward prismatic shift of the visual field is known to improve a wide range of hemispatial neglect symptoms, including visuo-manual tasks, mental imagery, postural imbalance, visuo-verbal measures and number bisection. The aim of the present study was to assess whether the beneficial effects of prism adaptation may generalize to auditory manifestations of neglect. Auditory extinction, whose clinical manifestations are independent of the sensory modalities engaged in visuo-manual adaptation, was examined in neglect patients before and after prism adaptation. Two separate groups of neglect patients (all of whom exhibited left auditory extinction) underwent prism adaptation: one group (n = 6) received a classical prism treatment ('Prism' group), the other group (n = 6) was submitted to the same procedure, but wore neutral glasses creating no optical shift (placebo 'Control' group). Auditory extinction was assessed by means of a dichotic listening task performed three times: prior to prism exposure (pre-test), upon prism removal (0 h post-test) and 2 h later (2 h post-test). The total number of correct responses, the lateralization index (detection asymmetry between the two ears) and the number of left-right fusion errors were analysed. Our results demonstrate that prism adaptation can improve left auditory extinction, thus revealing transfer of benefit to a sensory modality that is orthogonal to the visual, proprioceptive and motor modalities directly implicated in the visuo-motor adaptive process. The observed benefit was specific to the detection asymmetry between the two ears and did not affect the total number of responses. This indicates a specific effect of prism adaptation on lateralized processes rather than on general arousal. Our results suggest that the effects of prism adaptation can extend to unexposed sensory systems. The bottom-up approach of visuo-motor adaptation appears to interact with higher order brain functions related to multisensory integration and can have beneficial effects on sensory processing in different modalities. These findings should stimulate the development of therapeutic approaches aimed at bypassing the affected sensory processing modality by adapting other sensory modalities.

Looking while imagining: the influence of visual input on representational neglect.

BACKGROUND: Subjects with hemispatial neglect often exhibit representational neglect: a failure to report details from the left side of mentally visualized images. This failure could reflect impaired ability to generate the left side of the mental image, or it could reflect failure to explore the left side of a normally generated mental image. When subjects with hemispatial neglect look at pictures or drawings, their attention tends to be drawn to objects on the right side, thereby aggravating their failure to explore the left side. If representational neglect represents a failure to explore the left side of a normally generated mental visual image, then it should be improved by blindfolding, which removes the attention-catching right-sided stimuli. However, if representational neglect represents a failure to generate the left side of the mental visual image, then blindfolding should have little impact on reporting of details of the image. METHODS: To determine which of these explanations is correct, we asked eight normal participants and eight brain-damaged patients with left representational neglect to imagine the map of France and to name as many towns as possible in 2 minutes. In different sessions, participants performed the task with eyes open or while blindfolded. RESULTS: Normal participants mentioned more towns while blindfolded than with vision, thus suggesting a distracting effect of visual details on mental imagery. Patients with neglect, however, showed no appreciable effect of blindfolding on reporting of details from either side of mental images. CONCLUSION: Representational neglect may represent a failure to generate the left side of mental images.

Visually guided reaching: bilateral posterior parietal lesions cause a switch from fast visuomotor to slow cognitive control.

The visually guided reaching of two patients with bilateral optic ataxia was explored in two experiments. In Experiment 1 simple delayed pointing was compared with immediate pointing. In the immediate pointing task both variable and constant errors increased with target eccentricity. In contrast to the performance of control subjects and contrary to their own beliefs, the patients both showed improved accuracy in the delay condition. This improvement was manifest as a reduction in both pointing variability and in the constant angular error towards the point of fixation. Both angular errors and their improvement with the delay were proportional to target eccentricity. Experiment 2 used a task in which the target was pre-viewed 5s prior to its re-exposure for pointing ('delayed real pointing'). On some trials a conflict was introduced between the present and previous visual information by changing the target's location during the delay. In contrast to control subjects, who ignored the pre-viewed location and aimed directly at the current target, both patients with optic ataxia initiated their movements towards the previously viewed target location. Evidently they relied on off-line information in preference to on-line visual information. In addition, the patients often failed to detect the changes in target location. One of the patients sometimes even guessed incorrectly that the target had changed its location, and her movement trajectory was then more affected by her false belief than by the target's actual location. These findings confirm that posterior parietal lesions severely disrupt direct visuomotor transformations, and suggest that the residual performance is mediated indirectly by expectations or beliefs about target position.

Prism adaptation improves representational neglect.

Previous work has shown that various symptoms of unilateral neglect, including the pathological shift of the subjective midline to the right, may be improved by a short adaptation period to a prismatic shift of the visual field to the right. We report here, in two neglect patients the improvement of imagery neglect after prism exposure. Despite a strong neglect observed for mental images, as well as for conventional tests, the mental evocation of left-sided information from an internal image of the map of France was fully recovered following prism adaptation to the right. This improvement could not be explained by the alteration of visuomotor responses induced by the prism adaptation. Therefore, prism adaptation may act not only on sensory-motor levels but also on a higher cognitive level of mental space representation and/or exploration.

Implicit processing of somaesthetic information: a dissociation between where and how?

We present the case of a patient with a lesion of the thalamus who was completely anaesthetized on his right side. He was unable to detect and describe a tactile stimulus applied to his affected right arm, but could direct his normal left hand toward the specific right hand site where the stimulus had been applied when so instructed ('blind touch'). Strikingly, this pointing ability disappeared when the patient had to indicate on a picture of an arm where the stimulus was applied, and when he had to name the stimulus location during his pointing. Similar results were also obtained for localizing the unfelt fingertip ('blind proprioception'). Neuropsychological case studies have demonstrated that brain lesions can produce reciprocal dissociations between object identification (what is the object) and object-oriented action (how to direct a movement to the object). Along these lines, it is suggested that our patient exhibited a dissociation between a 'where' system and a 'how' system for tactile and proprioceptive stimuli.