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Articles by A. J. Lees
Total Records ( 3 ) for A. J. Lees
  M Selikhova , D. R Williams , P. A Kempster , J. L Holton , T Revesz and A. J. Lees
 

We have carried out a systematic review of the case files of 242 donors with pathologically verified Parkinson's disease at the Queen Square Brain Bank for Neurological Disorders in an attempt to corroborate the data-driven subtype classification proposed by Lewis and colleagues (Heterogeneity of Parkinson's disease in the early clinical stages using a data driven approach. J Neurol Neurosurg Psychiatry 2005; 76: 343–8). Cases were segregated into earlier disease onset (25%), tremor dominant (31%), non-tremor dominant (36%) and rapid disease progression without dementia (8%) subgroups. We found a strong association between a non-tremor dominant disease pattern and cognitive disability. The earlier disease onset group had the longest duration to death, and greatest delay to the onset of falls and cognitive decline. Patients with a tremor dominant disease pattern did not live significantly longer than non-tremor dominant patients and showed no difference in mean time to onset of falls and hallucinations. Rapid disease progression was associated with older age, early depression and early midline motor symptoms, and in 70% of the cases, tremulous onset. The non-tremor dominant subgroup had a significantly higher mean pathological grading of cortical Lewy bodies than all other groupings (P < 0.05) and more cortical amyloid-β plaque load and cerebral amyloid angiopathy than early disease onset and tremor dominant groups (P = 0.047). An analysis of cases with pathologically defined neocortical Lewy body disease confirmed the link between bradykinetic onset, cognitive decline and Lewy body deposition in the neocortex. Although neuropathological examination failed to distinguish the other subtypes, the classification scheme was supported by an analysis of clinical data that were independent of the basic subgroup definitions.

  M Jahanshahi , C. R. G Jones , J Zijlmans , R Katzenschlager , L Lee , N Quinn , C. D Frith and A. J. Lees
 

Patients with Parkinson’s disease experience motor and perceptual timing difficulties, which are ameliorated by dopaminergic medication. We investigated the neural correlates of motor timing in Parkinson’s disease, including the effects of dopaminergic medication on patterns of brain activation. Eight patients with Parkinson’s disease and eight healthy controls were scanned with H152 positron emission tomography while engaged in three tasks: synchronization (right index finger tapping in synchrony with a tone presented at 1 Hz), continuation (tapping at 1 Hz in the absence of a tone), and a control simple reaction time task. During the first 6 scans, the patients were assessed after overnight withdrawal of medication. Scans 7–12 were completed with the patients in the ‘ON’ state, after injections of apomorphine, a dopamine receptor agonist. For the healthy controls, relative to the control reaction time task, motor timing (synchronization + continuation) was associated with significantly greater activation in left medial prefrontal cortex (Brodmann area 10, 32), right hippocampus, bilateral angular gyrus (Brodmann area 39), left posterior cingulate (Brodmann area 31) and left nucleus accumbens/caudate. This pattern of brain activation during motor timing was not observed for patients, who showed significantly greater activation in bilateral cerebellum, right thalamus and left midbrain/substantia nigra compared to the control participants. Relative to the externally-paced synchronization task, the internally controlled continuation task was associated with greater activation in the dorsolateral prefrontal cortex (Brodmann area 46/9) in both the control and Parkinson’s disease groups. Analysis of medication-related effects indicated that cortical activation was significantly more predominant during motor timing when the patients were ‘ON’ medication, whereas pallidal and cerebellar activations were evident ‘OFF’ medication. Effective connectivity analysis established that activity in the left caudate nucleus was associated with increased activity in the right lentiform nucleus and cerebellum ‘OFF’ medication, and with increased activity in the prefrontal cortex ‘ON’ medication. These results suggest that in Parkinson’s disease, in the ‘OFF’ medication state, excessive inhibitory pallidal outflow is associated with a lack of adequate frontal activation and reliance on the cerebellum for motor timing. In contrast, our results establish for the first time that administration of dopaminergic medication increases striatal-frontal connectivity between the caudate nucleus and prefrontal cortex during motor timing.

  H Ling , S. S O'Sullivan , J. L Holton , T Revesz , L. A Massey , D. R Williams , D. C Paviour and A. J. Lees
 

The pathological findings of corticobasal degeneration are associated with several distinct clinical syndromes, and the corticobasal syndrome has been linked with a number of diverse pathologies. We have reviewed all the archival cases in the Queen Square Brain Bank for Neurological Disorders over a 20-year period with either a clinical diagnosis of corticobasal syndrome or pathological diagnosis of corticobasal degeneration in an attempt to identify the main diagnostic pitfalls. Of 19 pathologically confirmed corticobasal degeneration cases, only five had been diagnosed correctly in life (sensitivity = 26.3%) and four of these had received an alternative earlier diagnosis. All five of these had a unilateral presentation, clumsy useless limb, limb apraxia and myoclonus, four had cortical sensory impairment and focal limb dystonia and three had an alien limb. Eight cases of corticobasal degeneration had been clinically diagnosed as progressive supranuclear palsy, all of whom had vertical supranuclear palsy and seven had falls within the first 2 years. On the other hand, of 21 cases with a clinical diagnosis of corticobasal syndrome, only five had corticobasal degeneration pathology, giving a positive predictive value of 23.8%; six others had progressive supranuclear palsy pathology, five had Alzheimer’s disease and the remaining five had other non-tau pathologies. Corticobasal degeneration can present very commonly with a clinical picture closely resembling classical progressive supranuclear palsy or Richardson’s syndrome, and we propose the term corticobasal degeneration-Richardson’s syndrome for this subgroup. Cases of corticobasal degeneration-Richardson’s syndrome have delayed onset of vertical supranuclear gaze palsy (>3 years after onset of first symptom) and the infrequent occurrence of predominant downgaze abnormalities, both of which can be helpful pointers to their underlying corticobasal degeneration pathology. Fourty-two per cent of corticobasal degeneration cases presented clinically with a progressive supranuclear palsy phenotype and 29% of cases with corticobasal syndrome had underlying progressive supranuclear palsy pathology. In contrast, in the Queen Square Brain Bank archival collection, corticobasal syndrome is a rare clinical presentation of progressive supranuclear palsy occurring in only 6 of the 179 pathologically diagnosed progressive supranuclear palsy cases (3%). Despite these diagnostic difficulties we conclude that corticobasal degeneration is a discrete clinicopathological entity but with a broader clinical spectrum than was originally proposed.

 
 
 
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