This is a follow on to Dr. David Williams’ research at the Queen Square Brain Bank in London on PSP. He argues that there are three different types of PSP. The least common type he calls “pure akinesia with gait freezing” (PAGF). He recently published a paper on PAGF. The abstract follows.
Movement Disorders. 2007 Aug 21; [Epub ahead of print]
Pure akinesia with gait freezing: A third clinical phenotype of progressive supranuclear palsy.
Williams DR, Holton JL, Strand K, Revesz T, Lees AJ.
Faculty of Medicine (Neurosciences), Monash University (Alfred Hospital Campus), Melbourne, Australia.
The clinical syndrome of pure akinesia has most often been associated with progressive supranuclear palsy (PSP) and is characterized by difficulty initiating gait and “freezing” during walking, writing and speaking. Similar syndromes have been described under the rubrics of primary progressive freezing gait and primary gait ignition failure. We investigated the specificity of the clinical syndrome of pure akinesia with gait freezing (PAGF) for PSP-tau pathology. Among 749 patients archived at the QSBB, only 7 fulfilled proposed diagnostic criteria of: gradual onset of freezing of gait or speech; absent limb rigidity and tremor; no sustained response to levodopa; and no dementia or ophthalmoplegia in the first 5 years of disease. In these cases detailed pathological examination was performed. PSP was the pathological diagnosis in six patients, and Parkinson’s disease (PD) in the seventh. As defined, this syndrome had a positive predictive value of 86% for PSP-tau pathology. In the cases with PSP there were no additional features of coexistent vascular or PD and the median PSP-tau score was 3, reflecting relative mild tau load. The clinical syndrome of PAGF appears to have a high specificity for PSP-tau pathology. This relatively uncommon presentation of PSP-tau pathology has less severe tau accumulation than in the more common, “classic” PSP clinical phenotype: Richardson’s disease.
PubMed ID#: 17712855