Effect of rhythmic auditory stimulation on gait in Parkinsonian patients with and without freezing of gait

[Abstract] Freezing of gait (FOG) in Parkinson’s disease (PD) rises in prevalence when the effect of medications decays. It is known that auditory rhythmic stimulation improves gait in patients without FOG (PD-FOG), but its putative effect on patients with FOG (PD+FOG) at the end of dose has not been evaluated yet. This work evaluates the effect of auditory rhythmic stimulation on PD+FOG at the end of dose. 10 PD+FOG and 9 PD-FOG patients both at the end of dose periods, and 10 healthy controls were asked to perform several walking tasks. Tasks were performed in the presence and absence of auditory sensory stimulation. All PD+FOG suffered FOG during the task. The presence of auditory rhythmic stimulation (10% above preferred walking cadence) led PD+FOG to significantly reduce FOG. Velocity and cadence were increased, and turn time reduced in all groups. We conclude that auditory stimulation at the frequency proposed may be useful to avoid freezing episodes in PD+FOG.Xunta de Galicia; 2007/000140-0Xunta de Galicia; PGIDIT06PXIC137004P

Sight and insight – on the physiological role of nitric oxide in the visual system

[Abstract] Research in the fields of cellular communication and signal transduction in the brain has moved very rapidly in recent years. Nitric oxide (NO) is one of the latest discoveries in the arena of messenger molecules. Current evidence indicates that, in visual system, NO is produced in both postsynaptic and presynaptic structures and acts as a neurotransmitter, albeit of a rather unorthodox type. Under certain conditions it can switch roles to become either a neuronal ‘friend’ or ‘foe’. Nitric oxide is a gas that diffuses through all physiological barriers to act on neighbouring cells across an extensive volume on a specific time scale. It, therefore, has the opportunity to control the processing of vision from the lowest level of retinal transduction to the control of neuronal excitability in the visual cortex.Xunta de Galicia; XUGA13401B96Ministerio de Educación y Cultura; FIS97/040

Effects of rhythmic sensory stimulation (auditory, visual) on gait in Parkinson’s disease patients

[Abstract] This study has focused on how sensory stimulation affects gait in Parkinson’s disease (PD). The kinematic parameters of gait [cadence, step amplitude, velocity, coefficient of variation of stride time (CVstride-time), and the coefficient of variation of the step amplitude (CVstep-amplitude)] were analysed in 25 PD patients and 10 control subjects. Step amplitude, velocity and CVstride-time were altered in the patients with PD. However, when kinematic parameters were analysed as a function of disease severity, none of the parameters differed between early PD (I–II Hoehn and Yahr) and the controls. Nevertheless, more severely affected PD patients (III–IV Hoehn and Yahr) walked with a reduced step amplitude, lower velocity, higher CVstride-time, and higher CVstep-amplitude than the controls. The administration of auditory stimulation at a frequency matching the preferred walking cadence led to a decrease in the CVstride-time in PDIII–IV patients, and to an increase in step amplitude in PDIII–IV and controls. Visual stimulation at the same frequency did not modify any of the altered kinematic parameters in PDIII–IV patients. When different stimulation frequencies were utilised, auditory stimulation significantly changed some of the altered walking parameters in Parkinson patients. Frequencies matching preferred walking cadence or above this, up to the fastest walking, were those that seem to interact most effectively with the abnormal kinematic parameters in PDIII–IV patients. Visual stimulation negatively modulated cadence in PDIII–IV in the frequency range used. Sensory stimulation facilitates gait in PD. Studies using sensory stimulation as a tool to facilitate walking should take into account the grade of disability of the patients.Galicia. Consellería de Innovación, Industria e Comercio; PGIDIT06PXIC137004PNGalicia. Consellería de Educación; 2007/000140-

A simple, repeated rTMS protocol effectively removes auditory verbal hallucinations in a single patient study

Letter to the Edito

Looking back: corticothalamic feedback and early visual processing

[Abstract] Although once regarded as a simple sensory relay on the way to the cortex, it is increasingly apparent that the thalamus has a role in the ongoing moment-by-moment processing of sensory input and in cognition. This involves extensive corticofugal feedback connections and the interplay of these with the local thalamic circuitry and the other converging inputs. Here, using the feline visual system as the primary model, some of the latest developments in this field are reviewed and placed in the perspective of an integrated view of system function. Cortical feedback mediated by ionotropic and metabotropic glutamate receptors, and effects mediated by the neuromodulator nitric oxide, all have a role in integrating the thalamic mechanism into the cortical circuit. The essential point is that the perspective of higher-level sensory mechanisms shifts and modulates the thalamic circuitry in ways that optimize abstraction of a meaningful representation of the external world. This review is part of the TINS special issue on The Neural Substrates of Cognition.Ministerio de Ciencia y Tecnología; BFI2002–320

A simple procedure using auditory stimuli to improve movement in Parkinson´s disease: a pilot study

[Abstract] It has been suggested that sequential movements in Parkinsonian patients might be improved by the effects of external rhythmic cues, either visual or acoustic, acting as a sort of timekeeper. In lin e with that idea, we have developed a portable system which allows the patient suffe ring from bradykinesia and rigidity to initiate appropriate auditory stimulation when he/she is not able to move . Here we present data from six Parkinson’s Disease (PD) patients studied with surface electromyography, while walking along an 8.5m walkway . All showed remarkable improvement in the EMG parameters studied while using the device. The results are consistent with prior reports on rhythmic auditory facilitation in Parkinson’s disease gait, and suggest that this repr esents a novel and inexpensive tool to help people afflicted by PD in daily motor performance

Aquatic therapy versus conventional land-based therapy for Parkinson's disease: an open-label pilot study

[Abstract] Objectives: To assess and compare 2 different protocols of physiotherapy (land or water therapy) for people with Parkinson’s disease (PD) focused on postural stability and self-movement, and to provide methodological information regarding progression within the program for a future larger trial. Design: Randomized, controlled, open-label pilot trial. Setting: Outpatients, Parkinson’s disease Center of Ferrol - Galicia (Spain). Participants: Individuals (N 11) with idiopathic PD in stages 2 or 3 according to the Hoehn and Yahr Scale completed the investigation (intervention period plus follow-up). Interventions: After baseline evaluations, participants were randomly assigned to a land-based therapy (active control group) or a water-based therapy (experimental group). Participants underwent individual sessions for 4 weeks, twice a week, for 45 minutes per session. Both interventions were matched in terms of exercise features, which were structured in stages with clear objectives and progression criteria to pass to the next phase. Main Outcome Measures: Participants underwent a first baseline assessment, a posttest immediately after 4 weeks of intervention, and a follow-up assessment after 17 days. Evaluations were performed OFF-dose after withholding medication for 12 hours. Functional assessments included the Functional Reach Test (FRT), the Berg Balance Scale (BBS), the UPDRS, the 5-m walk test, and the Timed Up and Go test. Results: A main effect of both therapies was seen for the FRT. Only the aquatic therapy group improved in the BBS and the UPDRS. Conclusions: In this pilot study, physiotherapy protocols produced improvement in postural stability in PD that was significantly larger after aquatic therapy. The intervention protocols are shown to be feasible and seem to be of value in amelioration of postural stability–related impairments in PD. Some of the methodological aspects detailed here can be used to design larger controlled trials.Galicia. Consellería de Educación; E04D043802BRGalicia. Consellería de Innovación, Industria e Comercio; PGIDIT06PXIB137036P

Visual response augmentation in cat (and macaque) LGN: potentiation by corticofugally mediated gain control in the temporal domain

[Abstract] Visual responses of neurons are dependent on the context of a stimulus, not only in spatial terms but also temporally, although evidence for temporally separate visual influences is meagre, based mainly on studies in the higher cortex. Here we demonstrate temporally induced elevation of visual responsiveness in cells in the lateral geniculate nucleus (LGN) of cat and monkey following a period of high intensity (elevated contrast) stimulation. This augmentation is seen in 40–70% (monkey–cat) of cells tested and of all subtypes. Peaking at ∼ 3 min following the period of intense stimulation, it can last for 10–12 min and can be repeated and summed in time. Furthermore, it is dependent on corticofugal input, is seen even when high contrast stimuli of orthogonal orientation are used and therefore results from a/any prior increase in activity in the retino-geniculo-striate pathway. We suggest that this reflects a general mechanism for control of visual responsiveness; both a flexible and dynamic means of changing effectiveness of thalamic activity as visual input changes, but also a mechanism which is an emergent property of the thalamo-cortico-thalamic loop.Xunta de Galicia; XUGA13401B96Ministerio de Educación y Cultura; FIS-97/040