Neurological Evaluations and the AMA Guidlines
E. Klimek MD FRCPC FAADEP 
Outcome Assessment
It is, in principle at least, a straight forward matter to derive an informed estimate of the degree to which an individual's capacity to carry out daily activities has been diminished. Several methods might be considered as an adjunct to the AMA Guides in central nervous system chronic disease. Because of the frequency with which these methods occurr in case reviews of neurodisability, a brief overview follows. The comments applicable to these assessment instruments are intended to be instructive and equally applicable to the Tables of impairment ratings found in the AMA Guides. 
In clinical practice, medical evaluators incorporate patient's subjective complaints, objective examination and ancillary investigations into an overall evaluation. From a practical perspective, outcome measurements commonly seen in examinee's files must be familiar to the evaluator. These outcome measurements are either global outcome measures which estimate severity of illness or activity of daily living measurements which estimate the burden the individual imposes on caregivers. Both methods allocate specific functions to ordinal steps to form a scale. These scales found utility in monitoring outcomes in large groups of patients when detailed studies of functions are not needed. They are often not sufficiently sensitive to monitor individual patients and may be limited to specific disorders and presume optimal effort by the patient. Patient satisfaction or quality of life modeling is not usually seen in case reviews but is arguably as important but not as firmly entrenched in outcome analysis. 
For the AADEP fellows it is important to recall that both types of outcome scales are used to: 
1. Provide an objective measure of function that can be reported, 
2. Monitor changes in functional level and care needs, 
3. Justify management decisions (Funding) 
4. Demonstrate treatment effect 
5. Confirm prognosis 
A simple example of an outcome assessment scale is the Glasgow Outcome Scale which should be clearly distinguished from the Glasgow Coma Scale. Outcome assessments have steps that are unequal but contiguous. This means that grade 2 is not twice as "bad" as a grade 1. 
Glasgow Outcome Scale 1
1. Good recovery 
2. Moderate disability 
3. Severe disability 
4. Vegetative 
5. Death 
Scales usually have a "ceiling" or a "basement" effect inherent in their design intent. In the Rancho Los Amigos Scale note that Grade 8 could be easily further subdivided and the patient can not be graded above grade 8. 
Rancho Los Amigos Scale
1. No response 
2. Generalized response 
3. Localized response 
4. Confused agitated 
5. Confused inappropriate 
6. Confused appropriate 
7. Automatic appropriate 
8. Purposeful appropriate 
Most outcome scales are validated in diverse disorders but one must be aware that validation does not ensure relevance to the the disorder in question. Some scales are clearly intended only for institutionalized patients. The most widely used scales in chronic neurologic disability are those based on activities of daily living. The most common scale in use is the Barthel Index. 
A Barthel Index 2 score of greater than 60 correlates with return home and of greater than 95 indicates independent selfcare. The draw back to the Barthel Index is its lack of inclusion of cognitive and language function. The shortcoming of this scale have encouraged enhanced scales with expanded subcategories. One such scale is the Functional Independence Measure 3 which adds communication (expression and comprehension) and social cognition (social interaction, problem solving and memory). 
Barthel Index
Feeding 
Moving from wheelchair to bed and return 
Personal toilet 
Getting on and off toilet 
Bathing self 
Walking on level surface 
Ascend and descend stairs 
Dressing 
Controlling bowels 
Controlling bladder 
The Rankin Disability Scale is another example of a well validated ordinal scale in wide use in outcome assessment. 
Rankin Disability Scale 4
Grade 1 No significant disability; able to carry out all usual duties of daily living 
Grade 2 Slight disability, unable to carry out some previous activities but able to look after own affairs without assistance 
Grade 3 Moderate disability, requiring some help but able to walk without assistance 
Grade 4 Moderately severe disability, unable to walk and attend to own bodily needs without assistance 
Grade 5 Severe disability, bedridden, incontinent and requiring constant nursing care and attention 
Quality of Life, Self Perception and Family Perception Scales
The outcome scales above rely upon direct observation and examination. The functional status of outpatients in their own social environments has also been addressed. Authors5 6 make a case for including "quality of life" measurements into outcome assessment of clinical trials and this concept has been accepted in independent medical evaluation of impairment or disability. Self reporting of perceived impairment (eg Oswestry Low Back Pain Disability Questionnaire7) is a valid measure of a person's perceived disability. It is notewirthy to the AADEP fellows that, as with the EDSS, the area in which disability emerges is at 40%. Experienced evaluators usually compare their own understanding of the case with the examinee's self perception as an aid into the possiblity of magnification of symptoms. 
In some studies it has been felt that observations made by family members may contribute to more acccurate assessment since clinicians may miss subtle changes. The GERRI scale 8 used 49 items of interest to evaluate the at home functioning of geriatric patients that were considered to be areas of cognitive functioning, social functioning and mood. For the AADEP fellow it is noteworthy that the mood component was least reliably estimated by raters since mood must often be verbalized in order to be evaluated. Items dependent upon verbalization of symptoms i.e. vicarious self-reporting not obtaining acceptable levels of reliability included: 
Selfratings of Unacceptable Reliability
Wakes up at night, 
Day time drowsiness, 
Awakens in the early morning and unable to go back to sleep, 
Poor appetite, 
Reports feeling faint and dizzy, 
Reports muscular aches and light backaches, 
Reports feeling tired and lacking energy, 
Sexually inappropriate, 
Reports feeling nervous, 
Reports pain in chest or heart, 
Reports heart irregularities (beating faster or pounding), 
Reports nausea, 
Reports stomach upset. 
Disease Specific Scales
A desireable feature in disease specific outcome scales is the inclusion of all manifestations of the disease of interest. Significance of the manifestation in terms of functional impairemnt may not be independently weighted. Most of these scales are examination-based to maximize objectivity. 
Multiple Sclerosis
In 1983 the Expanded Disability Status Scale 9 evolved and considered eight functional systems intended to be independent of each other and in combination reflect all manifestations of neurologic impairment in MS. These subsections were: pyramidal, cerebellar, brain stem. sensory, bowel bladder, visual, cerebral-total, cerebral-mentation and other. The first four refer to impairment of body parts below the head, while brain stem refers to cranial nerves 3 through 12. 
The points of relevance to AADEP fellows include: 
The EDSS has Steps 1.0 to 10.0 with 10.0 being death. 
The lowest grades (up to Step 4.0) presume the ability to ambulate fully for 500 meters and carry out full daily activities and are rating by determining impariment of functional systems and compiling a EDSS Step. 
Within the EDSS the principal of objective abnormality with no impairment of function is accepted with Step 3.0 being being mild impairment with out impeding normal functions except in rare individuals (steeple jacks or concert pianists). Graphing the EDSS gives the appearance of a Gaussian distribution implying that means and standard deviations could be calculated. 
Stroke
A stroke study published in 1985 was designed to observe the effect of hemodilution in ischemic stroke during the first 24 hours. The Scandinavian Stroke Scale was devised to assess medical impairment due to stroke and monitor outcome of treatment. 10 The SSS was subdivided into 9 sections comprising : consciousness, eye movements, arm power, hand power, leg power, orientation, speech, facial palsy and gait. While the study failed to define a benefit to treatment it prompted a series of other stroke-specific impairment scales. Later scales were notable in part due to the success or failure of the clinical trial with which they were associated as much as their inherent value including: the Canadian Neurologic Scale11, The European Stroke Scale12, the NINDS13 among others. As a practical choice at my institution the ESS was chosen by nursing staff as a compromise considering the nursing time required to administer the various scales (about 3 minutes). 
Dementia
In common use in screening patients with cognitive disorders is the Mini Mental State Exam. 14 To use the construction analogy further, this scale has an expanded window suitable for only a narrow segment of the spectrum of impairment. Using a score of 23 as a cutoff the sensitivity and specificity for the MMSE is 87% and 82% respectively for detecting delirium in hospitalized patients. The score of the MMSE does not provide a specific diagnosis; patients with dementia, delirium, retardation, schizophrenia or depression obtain low scores. 
Primary degenerative dementia is presumed to be equivalent to neuropathologically defined Alzheimer's disease for these outcome scales. Scales specifically designed for Dementia trials include the Global Deterioration Scale which identifies 7 stages of cognitive decline. 15 The Alzheimer's Disease Assessment Scale is a rating scale with 21 cognitive items of which 60% are weighted toward cognitive and memory tasks.16 The scale was tested on patients with patients that were screened for mild to moderate dementia and patients with severe behavioral dysfunction were not included. 
Epilepsy
Epilepsy is distinct among diseases for fleeting yet severe impairment attributable to the disorder. Infrequent seizures present little difficulty to disability evaluators because they can resort to well established clinical guidelines for recommendations. These usually involve limitation of driving privileges and job restrictions that may impose hazards upon the patient or population. In refractory epilepsy clinically significant changes in seizure frequency, type or severity are outcome measurements of interest in clinical trials. A validated patient-based seizure severity scale 17 reflects the attacks. The AADEP fellow might consider the clinically relevant features identified in the scale listed below when addressing these examinees. 

Liverpool Seizure Severity Scale
Percept Subscale 
1. Occurrence of attacks 
2. Predicting attacks 
3. Ability to fight off attacks 
4. Aura or warning with attacks 
5. Perception of control 
6. Clustering of attacks 
7. Attacks in sleep 
8. Prevention of daily activities 
Ictal/Post-ictal subscale 
1. Overall severity of the attack 
2. Length of loss of consciousness 
3. Smacking of lips or fidgeting 
4. Length of confusion 
5. Severity of confusion 
6. Falling to ground 
7. Headache following recovery 
8. Sleepiness following recovery 
9. Incontinence during attack 
10. Tongue biting during attack 
11. Injury during attack 
12. Rate of recovery from attack 
Outcome Assessment of the CNS/PNS per AMA Guides (4th ed.)
The physician is to evaluate a patient's health status and determine the presence or absence of an impairment. By definition an impairment is the loss, loss of use, or derangement of any body part, system or function or a condition that interferes with an individual's "activities of daily living". The AMA Guides define permanent as unlikely to change substantially and by more than 3% in the next year with or without medical treatment and is not likely to remit despite medical treatment. The physician is usually asked to determine disability subsequent ot the etablishment of impairment. An impaired individual who is able to accomplish a specific task with or without accomodation is neither handicapped nor disabled with regard to that task. 
Suggested Approach Overview
1. Identify the anatomic site(s) of injury : brain, cranial nerve, spinal cord, nerve root, nerve, muscle 
2. Identify the maximum impairment possible then grade severity. 
3. Brain impairment is graded by reference to hierarchical functional impairment. 
4. Cranial nerve impairment is grouped by function and often in diverse Chapters. 
5. Spinal Cord injury is in Chapter 3 (Table 72, 73, 74) DRE spine injury (Category VI, VII, VIII) 
6. Nerve root deficits; upper extremity Table 13 page 51: lower extremity Table 83 page 130 
7. Plexus impairment (Table 14 page 52) is for the upper extremity only. 
8. Nerve Deficits are defined for upper (Table 15 page 34) and lower extremity (Table 68 page 89). 
9. Specific distal nerve entrapments are defined for upper extremity only (Table 16 page 57). 
10. Avoid using functional impairment such as strength impairment (Table 34 page 65, Table 39 page 77) if anatomic impairment is available . 
11. Do not consider range of motion impairment if due to nerve injury. 
12. Recall impairment never exceeds amputation maximum: Arm (60% WPI) Leg (40%) 
13. Recall spinal cord never exceeds paraplegia (70-75% WPI) combined with upper extremity impairment. 
14. Document explicitly. 
15. Is it intuitively right (medically reasonable)? 
Forebrain Overview
consciousness and awareness
max 90% WPI persistent vegetative state; Table 4 page 142 
aphasia and communication
max 60% WPI complete inability to communicate or comprehend; Table 1 page 141 
mental status and integrative functioning
max 70% WPI unable to care for self; Table 2 page 142 
emotional and behavioral disturbance
max 70% WPI total dependence on another; Table 3 page 142 
preoccupation or obsession
"refer to Chapter 14" 
major motor or sensory abnormality
max 60% WPI Station and Gait Table 13 page 148
max 45-60% WPI One Impaired Arm Table 14 page 148
max 80% WPI Two Impaired Arms Table 15 page 148 
movement disorder
no specific guide available 
episodic disorders
syncope max 70% WPI risk of bodily injury without specific Dx; Table 22 page 152
convulsive max 70% WPI totally limits daily acivities; Table 5 page 143 
sleep and arousal
max 60% WPI unable to care for self Table 6 page 143 
Note: only the most severe is considered of first 5 and the remaining 4 combine with one of the first five. 
Consciousness and Awareness
ref. Page 8
"... a 95% to 100% whole person impairment is ... a state that is approaching death." 
max 90% WPI - persistent vegetative state (see Table 4 page 142) 
Aphasia and Communication
Aphasia is the verbal manifestation of communication disturbance. It is not a disturbance of phonation or articulation 
max 60% WPI (see Table 1 page 141) 
 expression 
 repetition 
 comprehension 
 dyslexia 
 dysgraphia 
 spelling 
 pantomime 
Mental Status and Integrative Functioning
 orientation 
 memory 
 attention 
 abstraction 
 judgement 
max 70% WPI (see table 2 page 142) 
Emotional or Behavioural Disturbance
Chapter 4 refers the reader to Chapter 14 
SSA regulations: 
 medically determinable 
 inability to work 
 at least 12 months
This recommends DSM III-R classification system.
max 70% WPI (see Table 3 page 142) 
Preoccupation or Obsession
"refer to Chapter 14" page 297 
"a diagnosis alone can not be the basis for determining the presence of a disability" 
"the basis is the severity of the individuals functional limitations" 
page 301 "...there are no precise measures of impairment in mental disorders" 
(see Table Chapter 14 page 301) 
Major Motor or Sensory Abnormalities
page 141 suggests
a) evaluate other organ system if relevant
b) evaluate ability to perform daily activities
Max WPI 60% (see Table 13, Station and Gait, page 148)
Max WPI 45-60% (see Table 14, One Impaired Arm, page 148)
Max WPI 80% (see Table 15, Two Impaired Arms, page 148)
Note that Handedness is recognized in Table 14
Movement Disorders
There is no specific guide available in the text. 
Episodic Disorders
defined as "Intermittent but persistent" 
 syncope (Table 22 page 152) max 70% WPI 
 convulsive (Table 5 page 143) max 70% WPI 
 sleep (Table 6 page 143) max 60% WPI 
 excludes sleep apnea (see Chapter 5 page 163) 
Cranial Nerves I - XII Overview
XX. Olfactory
max 5% WPI anosmia Chapter 4.1 page 144
max 3% WPI anosmia Chapter 9.3 page 231
XXI. Optic
max 85% WPI blind Chapter 4.1 Table 7&8 page 144
max 85% WPI blind Chapter 8.4 Table 6 page 218
XXII. Oculomotor
max 24% WPI blind one eye due to diplopia Chapter 8.3 Figure 3 page 217 
XXIII. Trochlear
max 24% WPI blind one eye due to diplopia Chapter 8.3 Figure 3 page 217 
XXIV. Trigeminal
max 35% WPI debilitating pain Chapter 4 Table 9 page 145 
XXV. Abducens
max 24% WPI blind one eye due to diplopia Chapter 8.3 Figure 3 page 217 
XXVI. Facial
max 45% WPI bilateral palsy Chapter 4 Table 10 page 146 
XXVII. Vestibular
max 95% WPI Chapter 9.1c page 228
max 70% WPI confinement may be needed Chapter 4 Table 11 page 146
Cochlear
max 35% WPI deaf Chapter 9 Table 3 page 228
max 6% WPI complete monaural hearing loss Chapter 9 Table 2 and 3 page 226 and 228 
XXVIII. Glossopharyngeal
max 35% WPI mute Chapter 9 Table 7 & 9 page 233/234 
XXIX. Vagus
max 60% WPI tube feed Chapter 9 Table 6 page 231 
XXX. Accessory
max 60% WPI swallowing/speech Chapter 9 Table 6 page 231
consider also Chapter 3 Cervical ROM 
XXXI. Hypoglossal
max 60% WPI choking Chapter 4 Table 12 

CASE EXAMPLE "Aldo"
History:
30 year old male firefighter presents to medical care with difficulty with vision. Ophthalmologic assessment determined "papilledema". 
Examination:
Neurologic examination reveals slight hearing loss right sensorineural pattern. 
Investigations:
(CT Head slide reveals right cerebellopontine angle mass) 
Therapy:
Neurosurgical removal of schwannoma with sacrifice of vestibulocochlear nerve. 
Impairment evaluation reveals:
 (Facial Slide demonstrates paralysis right CN VII) 
 No diplopia 
 Absent hearing Right 
 No ataxia 
Summary of Impairment Examination 

SITECN III, IV, VI CN V CN VII CN VIII vestibular CN VIII cochlear CN IX, X CN XI, XII IMPAIRMENTnilnilUnilateral paralysisnilabsent hearing rightnilnil DISABILITYnilnilTable 10 page 146nilChapter 9 page 224nilnil

Part A:
Calculate binaural hearing impairment from unilateral 100% hearing loss.
Binaural Impairment = ( 5 X 0% + 100%)/6 = 100%/6 = 16.6% (table 2 page 226 reads 16.8%) 
This is 6% WPI acording to Table 3 page 228 
Part B:
Impairment for CN VII "severe unilateral facial paralysis..." 5 - 19% WPI. 
Part C:
COMBINE WPI 19% and 6% (Table page 322) = 24% 
Comment: The duration of paralysis is in excess of two years. The possibility of hypoglossal nerve transplantation does not enter into this evaluation. 

Spinal Cord Impairment Overview
XXXVI. Complaints 
XXXVII. Minor Impairment 
XXXVIII. Radiculopathy 
XXXIX. Loss of Motion 
XL. Limb involvement (only C-spine) 
XLI. Long tract signs 
XLII. Cauda Equina +/- bowel/bladder 
XLIII. Paraplegia 
 max 75+% WPI Cervical spine Chapter 3 Table 73 page 110 
 max 75+% WPI Thoracic spine Chapter 3 Table 74 page 111 
 max 70+% WPI Lumbar spine Chapter 3 Table 72 page 110 
Maximum WPI is derived by combining additional features from category I, II, III, IV, V (usually radiculopathy or upper limb impairment) with VI, VII or VII. When classification is unclear guidance from differentiators is found in Table 71 (DRE Impairment Category Differentiators). 

CASE EXAMPLE "Earl"
History:
trauma with paralysis 1980, currently recurrent UTI and hypertensive crisis. 
Physical Exam:
 Indwelling Catheter 
 No sensation or movement in feet 
 Spinal level to sensation in upper arms. 
 Shoulder shrugs, Abducts and adducts. 
 Flexes elbow with palpable brachioradialis action. 
 No triceps action palpable. 
DX: Cervical cord injury C5-6
Impairment rating:
 Cervicothoracic Diagnosis Related Estimates Model (Chapter 3) 
 Page 104 DRE Cervicothoracic Category V: Severe upper extremity compromise 35% WPI 
 Page 105 DRE Cervicothoracic Category VII: Paraplegia 75% WPI 
 Combine 75% and 35% = 84% WPI 
Could Earl have an increased impairment rating if hypertensive crises are explored for consideration? No:"transient elevation of arterial pressure is the normal physiologic response to exercise or excitement." (page 185) 
Barthel Index for "Earl"
SCORE ITEM
5 Feeding 
 Moving from wheelchair to bed and return 
 Personal toilet 
 Getting on and off toilet
 Bathing self
 Walking on level surface
 Ascend and descend stairs
 Dressing 
 Controlling bowels
 Controlling bladder
TOTAL 5/100

References:
 1. Jennet B, Bond M. Assessment of Outcome after Severe Brain Damage: A Practical Scale. Lancet 1975:480-484 
 2. Mahoney FI, Barthel DW. Functional Evaluation; the Barthel Index. Md State Med J 1965;14:61-65 
 3. Guide for the Uniform Data Set for Medical Rehabilitation State University of New York at Buffalo; 1996 
 4. Rankin J. Cerebrovascular accidents in patients over the age of 60. Scott Med J 1957;2:200-215 
 5. Deyo RA, Andersson G, Bombardieer C, et al. Outcome Measures for Studying Patients with Low Back Pain Spine 1994;19:2032s-2036s 
 6. Chadwick D. Measuring Antiepileptic Therapies: The Patient vs. the Physician Viewpoint. Neurology 1994;44(S8):S24-S28 
 7. Fairbank J.C.T., Couper J., Davies J.B., et al. The Oswestry Low Back Pain Disability Questionaire. Physiotherapy 1960;66 
 8. Schwartz GE. Development and Validation of the Geriatric Evaluation by Relative's Rating Instrument (GERRI). Psychological Reports 1983;53:479-488 
 9. Kurztke JF. Rating Neurologic Impairment in Multiple Sclerosis: An Expanded Disability Status Scale (EDSS). Neurology 1983;33:144-52 
 10. Scandinavian Stroke Study Group. Multicenter Trial of Hemodilution in Ischemic Stroke - Background and Study Protocol. Stroke 1985;16:885-890 
 11. Cote R, Battista RN, Wolson C, et al. The Canadian Neurologic Scale; Validation and Reliability Assessment. Neurology 1989;5:638-643 
 12. Hantson L, De Weerdt W, De Keyser J, et al. The European Stroke Scale. Stroke 1994;25:2215-2219 
 13. The National Institute of Neurologic Disorders and Stroke r-TPA Stroke Study Group. Tissue Plasminogen Activator for Acute Ischemic Stroke. N Eng J Med 1995;333:1581-1587 
 14. Crum RM, Anthony JC, Bassett SS, Folstein MF. Population-Based Norms for the Mini-Mental State Examination by Age and Educational Level. JAMA 1993;269:2386-2391 
 15. Reisberg B, Ferris SH, DeLeon MJ, Crook T. The Global Deterioration Scale for Assessment of Of Primary Degnerative Dementia. Am J Psychiatry 1982;139:1136-113 
 16. Rosen WG, Mohs RC, Davis KI. A New Rating Scale for Alzheimer's Disease. Am J Psychiatry 1984;141:1356-1364 
 17. Baker G, Smith D, Dewey M, et al. The Development of Seizure Severity Scale as an Outcome Measure in Epilepsy. Epilepsy Res 1991;8:245-251 

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