This 2007 article is really about the 20% of the 152 patients studied with clinical diagnoses of PSP who had “predominant behavioral and cognitive presentation, often resulting in an incorrect initial diagnosis of dementia. Patients with this presentation were younger at onset, but did not differ in their disease progression into typical PSP.” These patients are described as having a “frontal presentation.” “Why patients with PSP with frontal presentation have an earlier age at onset is unclear. Future studies are needed to confirm our observations and additional data on educational level may clarify this issue.” The most common initial misdiagnosis was FTD, which makes sense given the younger age at onset.
These are the most interesting findings that relate to all 152 patients in the study (not just the 20% with a “frontal presentation”):
* Old age at onset (greater than 72 years), “the early presence of supranuclear gaze palsy, urge incontinence, dysphagia, as well as cognitive decline and falls were all associated with a reduced survival.”
* “The observed worse performance in the verbal fluency …emphasizes the importance of this sign, which may differentiate PSP from multiple system atrophy and PD.”
* “Two recent studies showed that the severity of frontal atrophy in patients with PSP correlated with the degree of executive dysfunction in patients with PSP.”
* “Another interesting finding is the correlation between the FAB and UPDRS scores in our study. This is in line with an observed association between behavioral changes and increased motor disability in one study, and between decline in FAB scores and increased midbrain atrophy in another study. It suggests that in PSP behavioral and cognitive changes occur in parallel with motor impairment.”
[Robin’s notes: FAB = Frontal Assessment Battery. I believe this short exam was designed by a French expert on PSP, Dr. Bruno Dubois along with others, including Dr. Irene Litvan, a US expert on PSP. UPDRS = Unified Parkinson’s Disease Rating Scale]* “A correct initial diagnosis of PSP found in only 26% of the present cohort is similar to that found in other studies, which may largely be explained by the absence of supranuclear gaze palsy in the initial phase. It has frequently led to the misdiagnosis of dementia in patients with neuropsychiatric features and to the misdiagnosis of PD in patients with bradykinesia and rigidity. … Our observations support the findings of Osaki et al. that the inclusion of frontal lobe signs and personality changes into diagnostic criteria may improve the positive predictive value of PSP.”
Here’s the abstract of the article:
Neurology. 2007 Aug 21;69(Eight):723-9.
Frontal presentation in progressive supranuclear palsy.
Kaat LD, Boon AJ, Kamphorst W, Ravid R, Duivenvoorden HJ, van Swieten JC.
Department of Neurology, Erasmus Medical Center, Rotterdam, The Netherlands.
BACKGROUND: Progressive supranuclear palsy (PSP) is a progressive hypokinetic rigid disorder with supranuclear gaze palsy and frequent falls. Although clinical consensus criteria are available, an atypical presentation may lead to clinical misdiagnosis in the initial phase. In the present study we investigated the clinical presentation of PSP and its relationship to initial clinical diagnosis and survival.
METHODS: We ascertained patients with PSP in a prospective cohort by nationwide referral from neurologists and nursing home physicians. All patients underwent a structural interview and clinical examination before entering the study. Medical records were reviewed for the presence of symptoms during the first 2 years.
RESULTS: A total of 152 patients ascertained between 2002 and 2005 fulfilled the international consensus criteria for PSP. Categorical principal component analysis of clinical symptoms within the first 2 years showed apart from a cluster of typical PSP symptoms, the clustering of cognitive dysfunction and behavioral changes. Further analysis showed that 20% of patients had a predominant frontal presentation with less than two other PSP symptoms. Survival analysis showed that this subgroup had a similar prognosis to that of the total group of patients with PSP.
CONCLUSIONS: There exists a subgroup of patients with progressive supranuclear palsy (PSP) with a predominant frontal presentation, who progressed into typical PSP over the course of the disease.
PubMed ID#: 17709703 (see pubmed.gov for the abstract)