Gait freezing in parkinson's disease

8/18/2019 Gait freezing in parkinson's disease

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Gait freezing in Parkinson’sdisease and the stride

length sequence eectinteractionGroup 6


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Introduction

• Freezing of gait (FOG) paroxs!alpheno!enon co!!onl in ad"anced Parkinson’sdisease (te!porar pheno!enon #here the feetfailed to progress)$ the cause is poorlunderstood

• Freezing episodes are transient$ onl for a fe#seconds

• %end to increase in frequenc as the diseaseprogresses


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• FOG during #alking #as possi&l due tothe presence of the 'sequence eect’(gradual step to step reduction) in

co!&ination #ith an o"erall reduced steplength #hich$ if s!all enough$ #oulde"entuall lead to freezing


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%he i!

• to test the hpothesis that FOG$ during #alking$results #hen the sequence eect issuperi!posed on a reduced step length

• %he progressi"e reduction in step to stepa!plitude (sequence eect)$ !easured & alinear regression slope$ #as co!pared &et#eenParkinson’s disease participants #hoexperienced freezing (P* + FOG)$ those #ho didnot experience freezing (P* , FOG)$ as #ell as agroup of elderl control participants (control)


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Participants

• -6 participants #ith P* (#ith or #ithout FOG)

• P* + FOG (n . /6$ !ales . /0$ fe!ales . -)

• P* 1 FOG (n . /2$ !ales . 3$ fe!ale . /)

• P* + FOG !atched for aged #ith P* 1 FOG

• %he #ere 'o’ !edication

• 4ontrol group (participants #ith no fa!il

histor of P*)5 n . /2$ !ales . 3$ fe!ale . /


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Participant’s 4riteria

• &le to #alk total of -2 ! unaided

• 7o histor of other neurological conditions$

ortophaedics surger$ or an

!usculoskeletal disorders that could aect

gait

•

889: (8ini 8ental 9tate :xa!ination)score ; -0 -2


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• 4linical !easures5 the !otor section (III) of

the ?ni@ed Parkinson *isease Aating 9cale

(?P*A9)$ disease duration$ Boehn and

Cahr staging$ dan the FOG questionnaire


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GI%AiteD

• :lectronic #alk#a to !easure the spatial

and te!poral gait para!eters

• collects data through pressure sensors

e!&edded into the carpet$ !easuring E=!

long and 2E3! #ide

• alking speed$ cadence$ and step length

(intra,class correlations &et#een 2E- and

23- and coecients of "ariation &et#een

/0H and =H)


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dditional 8aterials

• ideotape recorder to facilitate

o&ser"ational analsis to score the

incidence of freezing episodes and allo#ed

repeat "ie#ing$ therefore increasing the

accurac of reporting


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Procedure

• Infor!ed concent$ !ental status$ height and

#eight !easure!ents

• Jeg length (to calculate nor!alized step length

Knor!alized step length . 2E x leg lengthL)

this calculated "alue of step length (/22H)$

further reductions of MH$ 2H and -H ofnor!alized step length (in centi!etre) #ere

calculated for each indi"idual and !arked out

on the Noor


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• Participants #ere instructed to #alk at a

self selected pace using the prescri&ed

step length to the line !arked -! &eond

the end of the !at to !ini!ize the risk of

slo#ing do#n

• ideo recording #as "ie#ed independentl& t#o assessors to count the nu!&er ofFOG episodes


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*ata nalsis

• 7O (One,#a analsis of "ariace) to

co!pare group descripti"e data and gait

characteristics for the three groups

• 4oecient of "aria&ilit calculated for all

groups and all conditions to deter!ine step

length "aria&ilit

•

P* + FOG

nu!&er of freezing epsiodes foreach condition totalled together to deter!ine

possi&le associations &et#een step length and

the nu!&er of freezing episodes


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• %he regression slope ()$ representing the

decrease or increase in step length for each

indi"idual #alk$ #ere a"eraged to for!ulate

group !ean a"erage slopes$ #hich #ere

co!piled for each condition (preferred$

9J/22$ 9JM$ 9J2 and 9J-)

• 4o!pared &et#een groups using a one,#a7O and %uke honestl signi@cant

dierence (B9*) post hoc test


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• FOG episodes and ,"alues and also freezingepisodes and clinical !easures (?P*A9$ BC$

889:$ G*9$ and FOG,Q) conducted &

Perason’s correlation coecient (r)

• ,"alues and clinical !easures for the P* +

FOG and P* 1 FOG also correlated using

Perason’s r

• r . 2/2 to 2-35 s!all$ r . 2=2 to 2035

!ediu!$ r . 22 to /2 large P,"alues < 22

indicated a signi@cant dierence (4ohen$ /3EE)


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A:9?J%9


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%a&le / 8eans and standard de"iations of screening !easuresand characteristics for P* + FOG$ P* 1 FOG and control groups


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PD + FOG PD - FOG

UPDRS /6 , =6(! . -=-R 9* .

0-)

3 , -/(! . /R 9* . =6M)

Duration = , -= ears(! . /-00R 9* .

22)

/ , E ears(! . -=2R 9* .

-0)

889: 5 no signi@cant dierences &et#een allgroups

G*9 5 P*+FOG is higher than P*,FOG control group

BC 5 P*+FOG is higher than P*,FOG$associated #ith the signi@cantdierences in duration of disease


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%a&le - 9patiote!poral characteristics of gait in preferredcondition for each group


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PD + FOG PD - FOG

9tep Jength s!aller &igger

elocit s!aller &igger

4adence no dierence no dierence

P* + FOG #alked #ith signi@cantl s!aller step

length and "elocit to the P* , FOG


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%a&le = 9u!!ar of a"erage step length and coecient of"aria&ilit (4OH) "alues for the three groups across conditionsfor each group


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• P* + FOG had a greater "aria&ilit step in9J$ especiall in -H and 2H conditions

• P* 1 FOG control group no dierence

in 9J "aria&ilit

• P* + FOG greater in 9J "aria&ilit in MH

co!pared to control group

• In 9J /22H$ P*+FOG had a greater

"aria&ilit$ &ut post hoc analsis results no

dierence


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nalsis for P*+FOG group5 nu!&erof freezing episodes

• %hrough FOG,Q P*+FOG reportedfreezing episode

• %otal counted freezing in P*+FOG 5 -0

Figure / () Number of freezing of gait episodes in ea! ondition in t!e PD+FOG group" (S) Number of FOG episodes in ea! ondition# in t!e subgroup


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nalsis &ased on a"erage slopes ()in each condition across all groups

• 9lopes for P*+FOG greater than P*,FOG

control group$ particularl at reduce 9J

•

7o dierence in 9J /22• "alue in 9J M$ 9J 2$ 9J - for P*+FOG

; P*,FOG control group

•

%uke’s B9* test

had a difference in located in P*+FOG co!pared to P*,FOG

control group


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Figure - () Re&ations!ip bet%een step &engt! and step numberfor a sing&e PD + FOG partiipant in t!e S' ondition" (S)Re&ations!ip bet%een step &engt! and step number for a sing&ePD FOG partiipant in t!e S' ondition" (4) Re&ations!ip

bet%een step &engt! and step number for a sing&e ontro&partiipant in t!e S' ondition"


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• Fig - P*+FOG participant had a

negati"e slope #ithin each #alking trial$

indicating the presence of the sequence

eect

• Fig -S4 P*,FOG control group #ere

a&le to !aintain a sta&le step length


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nalsis of slopes () in preferredcondition for P*+FOG group and it’s

relation to FOG episodes

%a&le 9u!!ar of b,"alues for P* +FOG group and signi@cance inpreferred condition and associated freezing episodes


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• %here #as a signi@cant negati"e

relationship &et#een the nu!&er of

freezing episodes and the preferred

a"erage slope$ indicating the nu!&er of

episode increase as the "alue of the slope

in the preferred #alking trials decreased

• %he freezing in 9J - correlated strongl

#ith the duration of disease

• %he nu!&er of freezing episode did not

correlate signi@cantl #ith BC$ ?P*A9$

FOG,Q$ 889:$ and G*9 scores


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*iscussion


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• %his stud exa!ined the hpothesis that

FOG during #alking in people #ith P*$ is

dependent upon &oth presence of the

sequence eect an adequatel reduced

9J to ena&le the step to step reduction of

the sequence eect lead to a !otor &lock

• 8otor &lock occurred onl in P*+FOG group

• reduction in 9J as a contri&uting factor to

FOG


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• "erage slopes #ere co!pared across all

groups

there #as a signi@cantdierence in the 9J M$ 9J 2$ and 9J -

nor!alize condition post hoc results the

dierence onl in P*+FOG group

• P*+FOG group had greater 9J "aria&ilt in

the conditions #hen freezing episodes!ore frequent,preferred$ 2H and -H

conditions


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• P*+FOG de!onstrated a signi@cantl greater

duration of disease$ higher FOG,Q scores$

?P*A9 and BC scores co!pared to P*,FOG

• %he !ore se"ere disease$ P*+FOG had

signi@cantl shorter 9J co!pared to P*,FOG control group

•

%here’s a strong association &et#een FO*and disease progression It #as o&ser"ed

that those #ho classi@ed as se"ere freezer

#ere attri&uted higher BC stages


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• *icult of e"aluating FOG although allparticipants in P*+FOG group reported

freezing in the FOG,Q$ @"e failed to freezeduring the testing session

•

7u!&er of freezing episodes didn’t correlate #ith the scores on FOG,Q

• s!all sa!ple size !a account for the

non,significant difference in &et#eengroups in preferred condition$ despite thefact that there #ere pro!inent "isi&ledierences in slopes


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• %he slopes are independent of these"aria&les #hich supports the hpothesis

that FOG is a result of decreased 9J in thepresence of the sequence eect

•

%he nu!&er of FOG episodes #as greatest#hen 9J #as reduced #hich suggest therisk of freezing !a increase on turning

• P*+FOG #alked at a preferred 9J "ersi!ilar to the 2H reduction of ideal 9J$ a"alue #here the !otor &locks &eca!e!ore frequent


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• %he factors that contri&uted to a !otor

&lock occurred in P*+FOG #ere the

sequence eect$ the preferred 9J of the

indi"idual$ the eect of !edication on the

&ackground stride length and the capacit

of the indi"idual to focus attention on

#alking


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4onclusion

• *e!onstrating that a reduction in step

length is one of the contri&uting factors to

FOG (support pre"ious research)

• Aeha&ilitati"e techniques should focus on

assisting Parkinson’s disease patients to

concentrate on !aintaining step length

during #alking episodes to pre"ent gait

diculties


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Gait freezing in parkinson's disease

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