This may not be helpful. I do find it a bit disappointing that these are the ONLY research studies I could find on this topic of "startle" and "falling" in PD.

redline.jpg

Startle responses in Parkinson patients during human gait.

1: Exp Brain Res. 2006 May;171(2):215-24. Epub 2005 Nov 24.Click here to read
http://www.ncbi.nlm.nih.gov/entrez/q...indexed=google

Department of Rehabilitation Medicine, Radboud University of Nijmegen Medical Center, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands.

Falls frequently occur in patients with Parkinson's disease (Bloem et al. 2001). One potential source for such falls during walking might be caused by the reaction to loud noises. In normal subjects startle reactions are well integrated in the locomotor activity (Nieuwenhuijzen et al. 2000), but whether this is also achieved in Parkinson patients is unknown. Therefore, in the present study, the startle response during walking was studied in eight patients with Parkinson's disease and in eight healthy subjects. To examine how startle reactions are incorporated in an ongoing gait pattern of these patients, unexpected auditory stimuli were presented in six phases of the step cycle during walking on a treadmill. For both legs electromyographic activity was recorded from biceps femoris and tibialis anterior. In addition, we measured the stance and swing phases of both legs, along with the knee angles of both legs and the left ankle angle. In all subjects and all muscles, responses were detected. The pattern of the responses, latency, duration, and phase-dependent modulation was similar in both groups. However, the mean response amplitude was larger in patients due to a smaller habituation rate. No correlation was found between the degree of habituation and disease severity. Moreover, a decreased habituation was already observed in mildly affected patients, indicating that habituation of the startle response is a sensitive measure of Parkinson's disease. The results complement the earlier findings of reduced habituation of blink responses in Parkinson's disease. With respect to behavioral changes in healthy subjects we observed that startle stimuli induced a shortening of the step cycle and a decrease in range of motion. In the patient group, less shortening of the subsequent step cycle and no decrease in range of motion of the knee and ankle was seen. It is argued that the observed changes might contribute to the high incidence of falls in patients with Parkinson's disease.

PMID: 16307244 [PubMed - in process]

redline.jpg

The auditory startle response in the Steele-Richardson-Olszewski syndrome and Parkinson's disease.

1: Brain. 1992 Aug;115 ( Pt 4):1181-92.Click here to read
http://www.ncbi.nlm.nih.gov/entrez/q...&dopt=Abstract

MRC Human Movement and Balance Unit, Institute of Neurology, Queen Square, London, UK.

The startle response to an unexpected auditory stimulus was studied in eight patients with a clinical diagnosis of the Steele-Richardson-Olszewski syndrome (SRO), 11 patients with idiopathic Parkinson's disease (PD) and 12 normal subjects. The patients with PD were studied 'on' at the time of maximal effect of their treatment; five of these patients were also studied in their 'off' state without treatment. The auditory startle response was absent in three patients with SRO: in the remaining five the latency to onset of earliest electromyography activity (EMG) of the auditory startle response was delayed and few muscles (orbicularis oculi, sternocleidomastoid and rectus abdominis) were recruited in the response. In PD the auditory startle response was similar to that recorded in normal subjects, both in terms of the pattern of muscles recruited and the amplitude of the EMG responses, but the latency of responses in orbicularis oculi and sternocleidomastoid muscles were significantly delayed. This result was not influenced by treatment with L-dopa. In patients with SRO the finding of an abnormal startle response is consistent with loss of neurons in the lower pontine reticular formation. This region is intimately involved in the startle response in animal studies. In patients with PD the late auditory startle response might be related to withdrawal of facilitatory input to brainstem centres and reticulospinal pathways from basal ganglia. The similarity of the responses in patients when 'on' and 'off' suggests these pathways are not under potent dopaminergic control.

PMID: 1393510 [PubMed - indexed for MEDLINE]

redline.jpg

Falling in Parkinson's disease: the impact on informal caregivers

Authors: Christine Davey a; Rose Wiles b; Ann Ashburn b; Caroline Murphy b
Affiliations: a North Yorkshire Alliance Research and Development Unit Bootham Park York UK.
b School of Health Professions and Rehabilitation Sciences University of Southampton UK.
DOI: 10.1080/09638280400000195
Publication Frequency: 24 issues per year
Published in: journal Disability & Rehabilitation, Volume 26, Issue 23 December 2004 , pages 1360 - 1366
Subject: Rehabilitation;
Formats available: PDF (English)
http://neurotalk.psychcentral.com/forumdisplay.php?f=34

Abstract
Purpose: The aim of this study was to explore the views and experiences of the informal caregivers of repeat fallers with Parkinson's disease. Method: Individuals were invited to participate in this study if they were the informal caregiver of a person with Parkinson's disease (PD) who had experienced more than one fall in the previous 12 months. Participants were interviewed about their experience of managing falls using a semi-structured interview schedule. Interview data were transcribed and analysed using thematic analysis. Results: Fourteen caregivers (11 female) participated in the study. All were marital partners of a repeat faller with Parkinson's disease. The average age of the participants was 69.9 years (44 - 79). Their partners had had PD for an average of 16.7 years. Six major themes emerged from the analysis of the interview data, four directly related to falls management (the falls; consequences of the falls for the person with PD; caregivers' experiences of falls; consequences of falls for the caregiver). The majority of caregivers were frightened about their spouse falling. They used a number of methods of getting their spouse up from the floor but often injured themselves as a consequence. Caregivers highlighted the high level of care they provided and the social and psychological impact of the condition on them. They received limited help in looking after their spouse and little information about falls or about the disease in general. Conclusion: Caregivers in this study felt unprepared for their role and expressed a need for more support and advice, especially about managing falls.

view citations (1)