View unanswered posts | View active topics It is currently Wed Nov 26, 2014 9:58 pm



Reply to topic  [ 9 posts ] 
 More Psychomotor Slowing in LBD than AD 
Author Message

Joined: Fri Aug 11, 2006 1:46 pm
Posts: 4811
Location: SF Bay Area (Northern CA)
Post More Psychomotor Slowing in LBD than AD
This French research concludes that psychomotor slowing (especially visual inspection time) is a useful diagnostic marker when evaluating someone for LBD or Alzheimer's, and when identifying "LBD patients at risk of hallucinations." In LBD, visual inspection time "was very impaired and correlated with visual hallucinations" while simple reaction time "lengthening was related to attentional disorders." The psychomotor slowing pattern was different for the AD group.

Visual inspection time test "is a discrimination task requiring the subject to determine which of two vertical lines (left or right) is the shortest." Subjects are looking at a 15" monitor where white stimuli were displayed at the center of the black screen.

In the simple reaction time test, letters are displayed randomly on the screen. The response "consisted of pressing one of two buttons" with the preferred hand when any of the letters is displayed.

Of course one key weakness of this study is that there is not pathological confirmation of the various diagnoses. The diagnostic accuracy (in the US) for LBD is less than 30%. The diagnostic accuracy for AD is much higher (75% plus).

I've copied the abstract below.

Robin



Here's the abstract:

Dementia and Geriatric Cognitive Disorders. 2010 May 20;29(5):388-396. [Epub ahead of print]

Psychomotor Slowing in Mild Cognitive Impairment, Alzheimer's Disease and Lewy Body Dementia: Mechanisms and Diagnostic Value.

Bailon O, Roussel M, Boucart M, Krystkowiak P, Godefroy O.
Department of Neurology and the Laboratoire de Neurosciences Fonctionnelles et Pathologies (UMR CNRS 8160), University Hospital of Lille, Lille, and University Hospital of Amiens, Amiens, France.

Abstract
Background: Although psychomotor slowing is frequent in Alzheimer's disease (AD) and Lewy body dementia (LBD), its mechanism and diagnostic value have not been examined.

Objective: To (i) assess psychomotor speed in patients with mild cognitive impairment (MCI), AD and LBD, (ii) determine the underlying mechanisms, and (iii) examine whether psychomotor slowing constitutes a useful diagnostic marker.

Methods: Psychomotor speed was assessed in MCI (n = 11) and mild dementia due to AD (n = 23) or LBD (n = 18) and controls (n = 52) with visual inspection time (VIT), digital tapping, simple reaction time (SRT) and choice reaction time (CRT) tests.

Results: MCI did not differ from controls.

Both dementia groups showed different patterns. In AD, VIT (p = 0.0001), tapping (p = 0.021), SRT (p = 0.0001) and decision time (p = 0.0001) were impaired as compared to controls. In LBD, VIT (p = 0.0001) was very impaired and correlated with visual hallucinations (p = 0.001); SRT lengthening (p = 0.0001) was related to attentional disorders (p = 0.0001).

Conclusions: Psychomotor slowing of AD is due to slower perceptuomotor and decision processes. In LBD, psychomotor slowing is due to visual and attention disorders, and subtle visual disorders contribute to hallucinations. VIT and CRT are useful diagnostic markers. Copyright © 2010 S. Karger AG, Basel.

PubMed ID#: 20484908 (see pubmed.gov for this abstract only)


Fri May 21, 2010 8:08 pm
Profile

Joined: Wed Dec 30, 2009 1:46 pm
Posts: 3213
Location: WA
Post 
Wow. I would never have guessed that hallucinations in LBD were a result of psychomotor slowing. But there have been a few instances where my husband has indicated a person standing in the living room and then, after a while, said, 'Oh, I guess it's the dog'. Is it just because it takes their brain so long to make the necessary analysis of the visual image, Robin?

Most of the time, though, he can specifically describe the person or object in question and it's nothing like what is there. Or am I totally missing the point this study has made? Thanks.
----------------------------------------
Pat [64] married to Derek [80] for 34 years; husband dx PDD/LBD 2005, probably began 2002-2003; Stage 3 or 4, depending. I am his caregiver at home.
----------------------------------------


Fri May 21, 2010 10:08 pm
Profile

Joined: Fri Aug 11, 2006 1:46 pm
Posts: 4811
Location: SF Bay Area (Northern CA)
Post 
I don't think hallucinations in LBD are as a result of psychomotor slowing. So my reading of the article was a bit different from yours.

I think the article is saying that severe psychomotor slowing is correlated with hallucinations.


Fri May 21, 2010 10:41 pm
Profile

Joined: Wed Dec 30, 2009 1:46 pm
Posts: 3213
Location: WA
Post 
Quote:
In LBD, psychomotor slowing is due to visual and attention disorders, and subtle visual disorders contribute to hallucinations
I guess that statement made me think that.


Fri May 21, 2010 11:17 pm
Profile

Joined: Sat Mar 28, 2009 6:01 pm
Posts: 101
Post 
Visual disorders, such as macular degeneration, contribute to a kind of hallucination known to opthomologists as Benet's Syndrome. For years before he had other Parkinson symptoms, my husband has been seeing things that are not there due to macular degeneration, or that is what we believed. They were always the same. Since his diagnosis of LBD, however, the images have changed, and he no longer can understand and discount them as consequences of his lost central vision. Due to the dementia, to him they are now real.

I have thought for some time that the many years he suffered from macular degeneration, even though he made a significant adjustment by using special reading machines, binoculars, etc. must have been a factor in the subsequent neurological degeneration. Luckily, he still retains peripheral vision -- he can look down and see his feet -- which is a big help in directing his movement during transfers.

I am sorry to say that he is declining more steeply these last few days, and needs much more comfort and reassurance to ease his anxiety about swallowing as he becomes weaker due to loss of weight and UTI symptoms. I think his hallucination (of a horse that comes into his room at night to eat the grass, he thinks, on a painting by his bed) actually calms him and keeps him from feeling alone. This is such a mysterious illness!

Doris

_________________
Bay Area, CA


Sat May 22, 2010 2:03 am
Profile

Joined: Fri May 29, 2009 10:06 am
Posts: 42
Post 
Robin,
Just relating to the above article, do you know if it's possible to have hallucinations with Alzheimers? My Mum has constant hallucinations, and delusions and seems so different to her neighbour in the nursing home who has Alzheimers. This lady just seems to be looking for her mother the whole time, and doesn't recognise her family when they come to visit.

If there are no hallucinations in Alzheimers, is this not one way of a positive diagnosis for LBD ( if there are hallucinations)?

annie41


Wed May 26, 2010 5:53 am
Profile

Joined: Fri Aug 11, 2006 1:46 pm
Posts: 4811
Location: SF Bay Area (Northern CA)
Post 
Yes, you can have hallucinations in AD. This usually happens later in the disease course. Not recognizing people is a sure sign of AD. But since LBD commonly co-occurs with AD, LBDers can experience this too.

There's a good comparison of AD, DLB, and PD in a newspaper article about MM and her husband:
http://community.lbda.org/forum/viewtopic.php?t=479 (scroll down)


Wed May 26, 2010 9:31 am
Profile

Joined: Wed Dec 30, 2009 1:46 pm
Posts: 3213
Location: WA
Post 
There must be a distinction between not recognizing people and Capgras Syndrome. My husband usually recognizes people and even remembers their names but most of the time doesn't know who I am--he thinks I'm one of a number of impostors who live here. And he has had hallucinations since early in the disease process.


Wed May 26, 2010 9:38 am
Profile

Joined: Fri Aug 11, 2006 1:46 pm
Posts: 4811
Location: SF Bay Area (Northern CA)
Post 
Since delusions are not a required diagnostic symptom for LBD, I don't think they are a useful differentiator.

Also, delusions can occur in AD. Not sure about Capgras specifically but Capgras is not unique to LBD.


Wed May 26, 2010 5:19 pm
Profile
Display posts from previous:  Sort by  
Reply to topic   [ 9 posts ] 

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group.
Designed by STSoftware for PTF.
Localized by Maël Soucaze © 2010 phpBB.fr