Pure apraxic agraphia with abnormal writing stroke sequences: report of a Japanese patient with a left superior parietal haemorrhage.
A 67 year old Japanese male patient had pure agraphia after a haemorrhage in the left superior parietal lobule. He developed difficulty in letter formation but showed no linguistic errors, consistent with the criteria of apraxic agraphia. He manifested a selective disorder of sequencing writing strokes, although he was able to orally state the correct sequences. The patient's complete recovery after 1 month, without new learning, showed that he had manifested a selective disorder of writing stroke sequences. These findings indicate that the final stage of the execution of writing according to acquired sequential memory shown as a stroke sequence can be selectively disturbed, and should be considered to be distinct from the ability of character imagery and the knowledge of the writing stroke sequence itself. This case also indicates that the left superior parietal lobule plays an important part in the execution of writing. (+info)
Impaired dexterity of the ipsilateral hand after stroke and the relationship to cognitive deficit.
BACKGROUND AND PURPOSE: Previous research has reported impaired hand function on the "unaffected" side after stroke, but its incidence, origins, and impact on rehabilitation remain unclear. This study investigated whether impairment of ipsilateral dexterity is common early after middle cerebral artery stroke and explored the relationship to cognitive deficit. METHODS: Thirty patients within 1 month of an infarct involving the parietal or posterior frontal lobe (15 left and 15 right hemisphere) used the ipsilateral hand in tests that simulated everyday hand functions. Performance was compared with that of healthy age-matched controls using the same hand. Standardized tests were used to assess apraxia, visuospatial ability, and aphasia. RESULTS: All patients were able to complete the dexterity tests, but video analysis showed that performance was slow and clumsy compared with that of controls (P<0.001). Impairment was most severe after left hemisphere damage, and apraxia was a strong correlate of increased dexterity errors (P<0.01), whereas reduced ipsilateral grip strength correlated with slowing (P<0.05). The pattern of performance was different for patients with right hemisphere damage. Here there was no correlation between grip strength and slowing, while dexterity errors appeared to be due to visuospatial problems. CONCLUSIONS: Subtle impairments in dexterity of the ipsilateral hand are common within 1 month of stroke. Ipsilateral sensorimotor losses may contribute to these impairments, but the major factor appears to be the presence of cognitive deficits affecting perception and control of action. The nature of these deficits varies with side of brain damage. The effect of impaired dexterity on functional outcome is not yet known. (+info)
Spatial deficits in ideomotor limb apraxia. A kinematic analysis of aiming movements.
Ideomotor limb apraxia is a classic neurological disorder manifesting as a breakdown in co-ordinated limb control with spatiotemporal deficits. We employed kinematic analyses of simple aiming movements in left hemisphere-damaged patients with and without limb apraxia and a normal control group to examine preprogramming and response implementation deficits in apraxia. Damage to the frontal and parietal lobes was more common in apraxics, but neither frontal nor parietal damage was associated with different arm movement deficits. Limb apraxia was associated with intact preprogramming but impaired response implementation. The response implementation deficits were characterized by spatial but not temporal deficits, consistent with decoupling of spatial and temporal features of movement in limb apraxia. While the apraxics' accuracy was normal when visual feedback was available, it was impaired when visual feedback of either target location or hand position was unavailable. This finding suggests that ideomotor limb apraxia is associated with disruption of the neural representations for the extrapersonal (spatial location) and intrapersonal (hand position) features of movement. The non-apraxic group's normal kinematic performance demonstrates that the deficits demonstrated in the apraxic group are not simply a reflection of left hemisphere damage per se. (+info)
Dyspraxia in a patient with corticobasal degeneration: the role of visual and tactile inputs to action.
OBJECTIVES: To investigate the roles of visual and tactile information in a dyspraxic patient with corticobasal degeneration (CBD) who showed dramatic facilitation in miming the use of a tool or object when he was given a tool to manipulate; and to study the nature of the praxic and neuropsychological deficits in CBD. METHODS: The subject had clinically diagnosed CBD, and exhibited alien limb behaviour and striking ideomotor dyspraxia. General neuropsychological evaluation focused on constructional and visuospatial abilities, calculation, verbal fluency, episodic and semantic memory, plus spelling and writing because impairments in this domain were presenting complaints. Four experiments assessed the roles of visual and tactile information in the facilitation of motor performance by tools. Experiment 1 evaluated the patient's performance of six limb transitive actions under six conditions: (1) after he described the relevant tool from memory, (2) after he was shown a line drawing of the tool, (3) after he was shown a real exemplar of the tool, (4) after he watched the experimenter perform the action, (5) while he was holding the tool, and (6) immediately after he had performed the action with the tool but with the tool removed from his grasp. Experiment 2 evaluated the use of the same six tools when the patient had tactile but no visual information (while he was blindfolded). Experiments 3 and 4 assessed performance of actions appropriate to the same six tools when the patient had either neutral or inappropriate tactile feedback-that is, while he was holding a non-tool object or a different tool. RESULTS: Miming of tool use was not facilitated by visual input; moreover, lack of visual information in the blindfolded condition did not reduce performance. The principal positive finding was a dramatic facilitation of the patient's ability to demonstrate object use when he was holding either the appropriate tool or a neutral object. Tools inappropriate to the requested action produced involuntary performance of the stimulus relevant action. CONCLUSIONS: Tactile stimulation was paramount in the facilitation of motor performance in tool use by this patient with CBD. This outcome suggests that tactile information should be included in models which hypothesise modality specific inputs to the action production system. Significant impairments in spelling and letter production that have not previously been reported in CBD have also been documented. (+info)
Perception of self-generated movement following left parietal lesion.
Three apraxic patients with lesions in the left parietal cortex were required to execute finger movements with either hand, while the visual feedback they received about the movement was manipulated systematically. We used a device which allowed us to present on a video monitor either the patient's hand or the examiner's hand simultaneously performing an identical or a different movement. In each trial, patients were required to decide whether the hand shown on the screen was their own or not. Hand movements produced in response to verbal command included simple (single-finger extension) and complex gestures (multi-finger extension). Ownership judgements were analysed and compared with those produced by six normal controls and two non-apraxic neurological patients. Apraxic patients and controls accurately recognized their own hand on the screen (own movement condition) and correctly identified the viewed hand as the examiner's when it performed a movement different from their own movement (incongruent movement condition). However, when the viewed hand was the examiner's hand executing their own movement (congruent movement condition), apraxic patients were significantly more impaired than controls. When the results were analysed as a function of gesture type, the number of correct responses was significantly lower for apraxic patients with respect to controls only for complex gestures. Interestingly, when patients executed the finger gestures inaccurately, they still failed to recognize the examiner's hand as alien, and claimed that the correct movement presented on the screen was their own. These results confirm that parietal lesions alter the representational aspects of gestures, and suggest a failure in evaluating and comparing internal and external feedback about movement. We conclude that the parietal cortex plays an important role in generating and maintaining a kinaesthetic model of ongoing movements. (+info)
Dark adaptation, motor skills, docosahexaenoic acid, and dyslexia.
Dyslexia is a widespread condition characterized by difficulty with learning and movement skills. It is frequently comorbid with dyspraxia (developmental coordination disorder), the chief characteristic of which is impaired movement skills, indicating that there may be some common biological basis to the conditions. Visual and central processing deficits have been found. The long-chain polyunsaturated fatty acids (LCPUFAs) are important components of retinal and brain membranes. In the preliminary studies reported here, dark adaptation was shown to be impaired in 10 dyslexic young adults when compared with a similar control group (P < 0.05, repeated-measures analysis of variance); dark adaptation improved in 5 dyslexia patients after supplementation with a docosahexaenoic acid (DHA)-rich fish oil for 1 mo (P < 0.05, paired t test on final rod threshold); and movement skills in a group of 15 dyspraxic children improved after 4 mo of supplementation with a mixture of high-DHA fish oil, evening primrose oil, and thyme oil (P < 0.007 for manual dexterity, P < 0.02 for ball skills, and P < 0.03 for static and dynamic balance; paired t tests). The studies were small and had designs that did not allow firm conclusions to be made. However, when considered with other evidence from another closely related condition, attention-deficit hyperactivity disorder, for which reduced ability to elongate and desaturate the essential fatty acids linoleic acid and alpha-linolenic acid to arachidonic acid and DHA, respectively, has been proposed, the studies suggest that more research, including double-blind, placebo-controlled studies, would be useful to clarify the benefits of LCPUFAs in dyslexia and other closely related conditions. (+info)
Portal systemic encephalopathy presenting with dressing and constructional apraxia.
We report a case with portal systemic encephalopathy who presented with dressing and constructional apraxia and subtle weakness of the left hand. We initially suspected a cerebrovascular attack in the right cerebral hemisphere, but brain T1-weighted magnetic resonance (MR) imaging revealed high intensity in the basal ganglia and hyperammonemia was detected. We performed abdominal MR angiography, which visualized an intrahepatic portal systemic shunt. Cerebral blood flow, measured by xenon-enhanced computed tomography, was decreased in the bilateral, but more dominantly right-sided, parietal watershed regions. We speculate that these boundary territories might be susceptible to damage by toxic metabolites of hepatic encephalopathy. (+info)
Worster-Drought syndrome, a mild tetraplegic perisylvian cerebral palsy. Review of 47 cases.
A retrospective case-note analysis was undertaken of 47 children with a congenital upper motor neurone bulbar palsy (excluding pure speech dyspraxia) to clarify the phenotype of Worster-Drought syndrome (WDS) and to record its associated features and complications. The results revealed that the study children had significant bulbar problems (with 80% still needing a modified diet and a similar number using augmentative communication methods at last review). There were also high rates of predictable bulbar complications (86% had dribbling, 60% had glue ear, gastro-oesophageal reflux in 40%, history of poor nutrition in 40% and aspiration in 40%). Most of the children had additional complex impairments (91% had mild pyramidal tetraplegia, 81% learning difficulties, 60% congenital defects, 41% neuropsychiatric problems and 28% epilepsy). Over half of the children had significant medical problems in the first year, but mean age at diagnosis was 6 years. There were no obvious causes in pregnancy or birth. Six children had a family history of WDS and 32% (12/37) had abnormal neuroimaging including five with bilateral perisylvian polymicrogyria. In our experience, WDS is not uncommon, is relatively easily diagnosed and is crucial not to miss as the management of these children's multiple impairments is complex and requires a careful team approach. WDS falls clearly within the cerebral palsies as a syndrome that includes motor impairment arising from static damage to the brain in early life. The common presence of cognitive, behavioural and seizure impairments strongly supports the cerebral cortical (presumably perisylvian) localization. Its core elements are a suprabulbar paresis, a mild spastic tetraplegia and a significant excess of cognitive and behavioural impairments and epilepsy. The complete overlap in phenotype between WDS and the bilateral perisylvian syndrome leads us to propose that they are the same condition. WDS is startlingly absent from epidemiological studies of the cerebral palsies and rarely diagnosed, presumably because of lack of clinical awareness of the condition and lack of major gross motor impairments. (+info)