This is fascinating German research comparing frequent fallers and infrequent fallers with a clinical diagnosis of PSP. The authors state:
“It is concluded that the occurrence of falls in PSP seems strongly associated with the deterioration of bulbar function, but not relevantly with typical parkinsonian features like rigidity and bradykinesia. The decreased ability to deal with distraction of attention under a dual-task situation points to a relevant impact of cortical and subcortical dysfunction on the frequency of falls.”
“Frequent fallers also showed an increased probability of an altered walking pattern with shortened step lengths and increased cadence under a dual-task situation.”
Frequent falling was not associated with disease duration.
Of the 26 cases studied, “13 patients suffered from Richardson’s syndrome (11 of them were frequent fallers, 2 were infrequent fallers), and 9 suffered from PSP-Parkinsonism (4 were frequent fallers, and 5 were infrequent fallers).” (One of the clinical characteristics of Richardson’s syndrome is unexplained falls as a primary symptom.) Four patients could not be assigned to a sub-type.
The “PSP Rating Scale” was used as part of the clinical investigation. These researchers described that scale as follows: “This scale comprises 28 items in six categories: daily activities (by history), behavior, bulbar, ocular motor, limb motor and gait/midline, and has been shown to be sensitive to disease diagnosis and progression.” The researchers found the PSP Rating Scale better at assessing subtle cognitive deficits in PSP than the MMSE or the FAB (Frontal Assessment Battery).
You can also find links to the scale itself and to Dr. Golbe’s research article about the scale) here:
http://forum.psp.org/viewtopic.php?t=2468 (see my post from 11/19/09)
I glanced over the full article today. I found these statements about postural instability very clear:
“It is obvious that postural instability cause falls. Postural stability may include sensory organization, a motor adjustment process, and the background tone of the muscles. Cognitive processes such as attention and learning are also important resources required for postural stability. In PSP, the visual system (due to gaze palsy) and motor adjustment processes are known to be defective, and cognitive slowing is regularly and early observed.”
The abstract is copied below. It’s quite good, compared to other abstracts.
Movement Disorders. 2010 Feb 3. [Epub ahead of print]
Clinical and dual-tasking aspects in frequent and infrequent fallers with progressive supranuclear palsy.
Lindemann U, Nicolai S, Beische D, Becker C, Srulijes K, Dietzel E, Bauer S, Berg D, Maetzler W.
Department of Clinical Gerontology, Robert-Bosch-Hospital, Stuttgart, Germany.
Progressive supranuclear palsy (PSP) is a rare neurodegenerative disease with no sufficient therapeutic options to date. Falls are the most devastating feature. The causes of these falls are not well understood.
To test the impact of PSP-associated motor and cognitive features on falls, 26 PSP patients were prospectively recruited and divided into frequent fallers (> one fall/month, 18 patients) and infrequent fallers (</= one fall/month, 8 patients). Further parameters were assessed by clinical investigation and biomechanical gait and balance analysis with and without dual-task paradigms. Physical activity was measured through an ambulatory device.
Frequent fallers scored higher on the total PSP rating scale and the subscales “history,” “mental,” “bulbar,” “supranuclear ocular motor,” and “gait/midline exam” but not on disease duration, the subscale “limb exam,” the UPDRS motor score and the sway analysis.
Frequent fallers also showed an increased probability of an altered walking pattern with shortened step lengths and increased cadence under a dual-task situation.
It is concluded that the occurrence of falls in PSP seems strongly associated with the deterioration of bulbar function, but not relevantly with typical parkinsonian features like rigidity and bradykinesia. The decreased ability to deal with distraction of attention under a dual-task situation points to a relevant impact of cortical and subcortical dysfunction on the frequency of falls.
PubMed ID#: 20131396 (see pubmed.gov for this abstract only)